Skip to main content

A framework for large-scale measurement platforms (LMAP)
draft-ietf-lmap-framework-04

The information below is for an old version of the document.
Document Type
This is an older version of an Internet-Draft that was ultimately published as RFC 7594.
Authors Philip Eardley , Al Morton , Marcelo Bagnulo , Trevor Burbridge , Paul Aitken, Aamer Akhter
Last updated 2014-03-31
Replaces draft-folks-lmap-framework
RFC stream Internet Engineering Task Force (IETF)
Formats
Reviews
Additional resources Mailing list discussion
Stream WG state WG Document
Document shepherd (None)
IESG IESG state Became RFC 7594 (Informational)
Consensus boilerplate Unknown
Telechat date (None)
Responsible AD Benoît Claise
Send notices to (None)
draft-ietf-lmap-framework-04
Network Working Group                                         P. Eardley
Internet-Draft                                                        BT
Intended status: Informational                                 A. Morton
Expires: October 2, 2014                                       AT&T Labs
                                                              M. Bagnulo
                                                                    UC3M
                                                            T. Burbridge
                                                                      BT
                                                               P. Aitken
                                                               A. Akhter
                                                           Cisco Systems
                                                          March 31, 2014

        A framework for large-scale measurement platforms (LMAP)
                      draft-ietf-lmap-framework-04

Abstract

   Measuring broadband service on a large scale requires a description
   of the logical architecture and standardisation of the key protocols
   that coordinate interactions between the components.  The document
   presents an overall framework for large-scale measurements.  It also
   defines terminology for LMAP (large-scale measurement platforms).

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on October 2, 2014.

Copyright Notice

   Copyright (c) 2014 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

Eardley, et al.          Expires October 2, 2014                [Page 1]
Internet-Draft               LMAP Framework                   March 2014

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Outline of an LMAP-based measurement system . . . . . . . . .   5
   3.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   8
   4.  Constraints . . . . . . . . . . . . . . . . . . . . . . . . .  11
     4.1.  Measurement system is under the direction of a single
           organisation  . . . . . . . . . . . . . . . . . . . . . .  11
     4.2.  Each MA may only have a single Controller at any point in
           time  . . . . . . . . . . . . . . . . . . . . . . . . . .  12
   5.  LMAP Protocol Model . . . . . . . . . . . . . . . . . . . . .  12
     5.1.  Bootstrapping process . . . . . . . . . . . . . . . . . .  13
     5.2.  Control Protocol  . . . . . . . . . . . . . . . . . . . .  14
       5.2.1.  Instruction . . . . . . . . . . . . . . . . . . . . .  14
       5.2.2.  Capabilities and Failure information  . . . . . . . .  17
     5.3.  Operation of Measurement Tasks  . . . . . . . . . . . . .  19
       5.3.1.  Starting and Stopping Measurement Tasks . . . . . . .  19
       5.3.2.  Overlapping Measurement Tasks . . . . . . . . . . . .  20
     5.4.  Report Protocol . . . . . . . . . . . . . . . . . . . . .  21
       5.4.1.  Reporting of Subsriber's service parameters . . . . .  22
     5.5.  Operation of LMAP over the underlying transport protocol   22
     5.6.  Items beyond the scope of the LMAP Protocol Model . . . .  23
       5.6.1.  End-user-controlled measurement system  . . . . . . .  24
   6.  Deployment considerations . . . . . . . . . . . . . . . . . .  25
     6.1.  Controller and the measurement system . . . . . . . . . .  25
     6.2.  Measurement Agent . . . . . . . . . . . . . . . . . . . .  26
       6.2.1.  Measurement Agent on a networked device . . . . . . .  26
       6.2.2.  Measurement Agent embedded in site gateway  . . . . .  26
       6.2.3.  Measurement Agent embedded behind site NAT /Firewall   27
       6.2.4.  Multi-homed Measurement Agent . . . . . . . . . . . .  27
     6.3.  Measurement Peer  . . . . . . . . . . . . . . . . . . . .  28
   7.  Security considerations . . . . . . . . . . . . . . . . . . .  28
   8.  Privacy Considerations for LMAP . . . . . . . . . . . . . . .  30
     8.1.  Categories of Entities with Information of Interest . . .  30
     8.2.  Examples of Sensitive Information . . . . . . . . . . . .  31
     8.3.  Key Distinction Between Active and Passive Measurement
           Tasks . . . . . . . . . . . . . . . . . . . . . . . . . .  32
     8.4.  Privacy analysis of the Communications Models . . . . . .  33

Eardley, et al.          Expires October 2, 2014                [Page 2]
Internet-Draft               LMAP Framework                   March 2014

       8.4.1.  MA Bootstrapping  . . . . . . . . . . . . . . . . . .  33
       8.4.2.  Controller <-> Measurement Agent  . . . . . . . . . .  34
       8.4.3.  Collector <-> Measurement Agent . . . . . . . . . . .  34
       8.4.4.  Measurement Peer <-> Measurement Agent  . . . . . . .  35
       8.4.5.  Passive Measurement Agent . . . . . . . . . . . . . .  36
       8.4.6.  Storage and Reporting of Measurement Results  . . . .  37
     8.5.  Threats . . . . . . . . . . . . . . . . . . . . . . . . .  37
       8.5.1.  Surveillance  . . . . . . . . . . . . . . . . . . . .  38
       8.5.2.  Stored Data Compromise  . . . . . . . . . . . . . . .  38
       8.5.3.  Correlation and Identification  . . . . . . . . . . .  39
       8.5.4.  Secondary Use and Disclosure  . . . . . . . . . . . .  39
     8.6.  Mitigations . . . . . . . . . . . . . . . . . . . . . . .  39
       8.6.1.  Data Minimisation . . . . . . . . . . . . . . . . . .  39
       8.6.2.  Anonymity . . . . . . . . . . . . . . . . . . . . . .  40
       8.6.3.  Pseudonymity  . . . . . . . . . . . . . . . . . . . .  41
       8.6.4.  Other Mitigations . . . . . . . . . . . . . . . . . .  41
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  42
   10. Appendix: Deployment examples . . . . . . . . . . . . . . . .  42
   11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  46
   12. History . . . . . . . . . . . . . . . . . . . . . . . . . . .  47
     12.1.  From -00 to -01  . . . . . . . . . . . . . . . . . . . .  47
     12.2.  From -01 to -02  . . . . . . . . . . . . . . . . . . . .  47
     12.3.  From -02 to -03  . . . . . . . . . . . . . . . . . . . .  48
     12.4.  From -03 to -04  . . . . . . . . . . . . . . . . . . . .  49
   13. Informative References  . . . . . . . . . . . . . . . . . . .  49
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  51

1.  Introduction

   There is a desire to be able to coordinate the execution of broadband
   measurements and the collection of measurement results across a large
   scale set of diverse devices.  These devices could be software based
   agents on PCs, embedded agents in consumer devices (e.g. blu-ray
   players), service provider controlled devices such as set-top players
   and home gateways, or simply dedicated probes.  It is expected that
   such a system could easily comprise 100,000 devices.  Such a scale
   presents unique problems in coordination, execution and measurement
   result collection.  Several use cases have been proposed for large-
   scale measurements including:

   o  Operators: to help plan their network and identify faults

   o  Regulators: to benchmark several network operators and support
      public policy development

   Further details of the use cases can be found in
   [I-D.ietf-lmap-use-cases].  The LMAP framework should be useful for

Eardley, et al.          Expires October 2, 2014                [Page 3]
Internet-Draft               LMAP Framework                   March 2014

   these, as well as other use cases, such as to help end users run
   diagnostic checks like a network speed test.

   The LMAP framework has three basic elements: Measurement Agents,
   Controllers and Collectors.

   Measurement Agents (MAs) perform the actual measurements, which are
   called Measurement Tasks in the LMAP terminology.

   The Controller manages one or more MAs by instructing it which
   Measurement Tasks it should perform and when.  For example it may
   instruct a MA at a home gateway: "Measure the 'UDP latency' with
   www.example.org; repeat every hour at xx.05".  The Controller also
   manages a MA by instructing it how to report the Measurement Results,
   for example: "Report results once a day in a batch at 4am".  We refer
   to these as the Measurement Schedule and Report Schedule.

   The Collector accepts Reports from the MAs with the Results from
   their Measurement Tasks.  Therefore the MA is a device that gets
   Instructions from the Controller, initiates the Measurement Tasks,
   and reports to the Collector.

   There are additional elements that are part of a measurement system,
   but these are out of the scope for LMAP.  We provide a detailed
   discussion of all the elements in the rest of the document.

   The desirable features for a large-scale measurement systems we are
   designing for are:

   o  Standardised - in terms of the Measurement Tasks that they
      perform, the components, the data models and protocols for
      transferring information between the components.  Amongst other
      things, standardisation enables meaningful comparisons of
      measurements made of the same metric at different times and
      places, and provides the operator of a measurement system with a
      criteria for evaluation of the different solutions that can be
      used for various purposes including buying decisions (such as
      buying the various components from different vendors).  Today's
      systems are proprietary in some or all of these aspects.

   o  Large-scale - [I-D.ietf-lmap-use-cases] envisages Measurement
      Agents in every home gateway and edge device such as set-top-boxes
      and tablet computers.  It is expected that a measurement system
      could easily encompass a few hundred thousand Measurement Agents.
      Existing systems have up to a few thousand MAs (without judging
      how much further they could scale).

Eardley, et al.          Expires October 2, 2014                [Page 4]
Internet-Draft               LMAP Framework                   March 2014

   o  Diversity - a measurement system should handle different types of
      Measurement Agent - for example Measurement Agents may come from
      different vendors, be in wired and wireless networks, have
      different Measurement Task capabilities and be on devices with
      IPv4 or IPv6 addresses.

2.  Outline of an LMAP-based measurement system

   Figure 1 shows the main components of a measurement system, and the
   interactions of those components.  Some of the components are outside
   the scope of LMAP.  In this section we provide an overview of the
   whole measurement system and we introduce the main terms needed for
   the LMAP framework.  The new terms are capitalised.  In the next
   section we provide a terminology section with a compilation of all
   the LMAP terms and their definition.

   The main work of the LMAP working group is to define the Control
   Protocol between the Controller and MA, and the Report Protocol
   between the MA and Collector.  Section 4 onwards considers the LMAP
   components in more detail.

   The MA performs Measurement Tasks.  The MAs are pieces of code that
   can be executed in specialised hardware (hardware probe) or on a
   general-purpose device (like a PC or mobile phone).  A device with a
   Measurement Agent may have multiple interfaces (WiFi, Ethernet, DSL,
   fibre, etc.) and the Measurement Tasks may specify any one of these.
   Measurement Tasks may be Active (the MA generates Active Measurement
   Traffic and measures some metric associated with its transfer),
   Passive (the MA observes user traffic), or some hybrid form of the
   two.

   The MA is managed by a Controller using the Control Protocol.  The MA
   receives Instructions from the Controller about which Measurement
   Tasks it should perform and when.  For example the Controller may
   instruct a MA at a home gateway: "Count the number of TCP SYN packets
   observed in a 1 minute interval; repeat every hour at xx.05 +
   Unif[0,180] seconds".  The Measurement Schedule determines when the
   Measurement Tasks are executed.  The Controller also manages a MA by
   instructing it how to report the Measurement Results, for example:
   "Report results once a day in a batch at 4am + Unif[0,180] seconds;
   if the end user is active then delay the report 5 minutes".  The
   Report Schedule determines when the Reports are uploaded to the
   Collector.  The Measurement chedule and Report Schedule can define
   one-off (non-recurring) actions ("Do measurement now", "Report as
   soon as possible"), as well as recurring ones.

Eardley, et al.          Expires October 2, 2014                [Page 5]
Internet-Draft               LMAP Framework                   March 2014

   The Collector accepts a Report from a MA with the Measurement Results
   from its Measurement Tasks.  It then provides the Results to a
   repository (see below).

   Some Measurement Tasks involve several MAs acting in a coordinated
   fashion.  This coordination is achieved by the Controller instructing
   the multiple MAs in a coherent manner.  In some Measurement Tasks the
   MA(s) is assisted by one or more network entities that are not
   managed by the Controller.  The entities that helps the MA in the
   Measurement Tasks but are not managed by the Controller are called
   Measurement Peers (MPs).  For example consider the case of a "ping"
   Measurement Task, to measure the round trip delay between the MA and
   a given ICMP ECHO responder in the Internet.  In this case, the
   responder is the Measurement Peer.  The ICMP ECHO request and ICMP
   ECHO Requests and Replies flowing between the MA and the MP is called
   Active Measurement Traffic.  The Appendix has some other examples of
   possible arrangements of Measurement Agents and Peers.

   A Measurement Method defines how to measure a Metric of interest.  It
   is very useful to standardise Measurement Methods, so that it is
   meaningful to compare measurements of the same Metric made at
   different times and places.  It is also useful to define a registry
   for commonly-used Metrics [I-D.manyfolks-ippm-metric-registry] so
   that a Measurement Method can be referred to simply by its identifier
   in the registry.  The Measurement Methods and registry will hopefully
   be referenced by other standards organisations.

   A Measurement Task is a specific instantiation of a Measurement
   Method.It generates a Measurement Result.  An Active Measurement Task
   involves either a Measurement Agent (MA) injecting Active Measurement
   Traffic into the network destined for a Measurement Peer or for
   another Measurement Agent, and/or a Measurement Peer (or another
   Measurement Agent) sending Active Measurement Traffic to a MA; one of
   them measures some parameter associated with the transfer of the
   packet(s).  A Passive Measurement Task involves a MA simply observing
   existing traffic - for example, it could count bytes or it might
   calculate the average loss for a particular flow.

   In order for a Measurement Agent and a Measurement Peer (or another
   Measurement Agent) to execute an Active Measurement Task, they
   exchange Active Measurement Traffic.  The protocols used for the
   Active Measurement Traffic are out of the scope of the LMAP WG; they
   fall within the scope of other IETF WGs such as IPPM.

   For Measurement Results to be truly comparable, as might be required
   by a regulator, not only do the same Measurement Methods need to be
   used but also the set of Measurement Tasks should follow a similar
   Measurement Schedule and be of similar number.  The details of such a

Eardley, et al.          Expires October 2, 2014                [Page 6]
Internet-Draft               LMAP Framework                   March 2014

   characterisation plan are beyond the scope of work in IETF although
   certainly facilitated by IETF's work.

   Finally we introduce several components that are out of scope of the
   LMAP WG and will be provided through existing protocols or
   applications.  They affect how the measurement system uses the
   Measurement Results and how it decides what set of Measurement Tasks
   to perform.

   The MA needs to be bootstrapped with initial details about its
   Controller, including authentication credentials.  The LMAP WG
   considers the bootstrap process, since it affects the Information
   Model.  However, it does not define a bootstrap protocol, since it is
   likely to be technology specific and could be defined by the
   Broadband Forum, CableLabs or IEEE depending on the device.  Possible
   protocols are SNMP, NETCONF or (for Home Gateways) CPE WAN Management
   Protocol (CWMP) from the Auto Configuration Server (ACS) (as
   specified in TR-069 [TR-069]).

   A Subscriber parameter database contains information about the line,
   such as the customer's broadband contract (perhaps 2, 40 or 80Mb/s),
   the line technology (DSL or fibre), the time zone where the MA is
   located, and the type of home gateway and MA.  These parameters are
   already gathered and stored by existing operations systems.  They may
   affect the choice of what Measurement Tasks to run and how to
   interpret the Measurement Results.  For example, a download test
   suitable for a line with an 80Mb/s contract may overwhelm a 2Mb/s
   line.

   A results repository records all Measurement Results in an equivalent
   form, for example an SQL database, so that they can easily be
   accessed by the data analysis tools.

   The data analysis tools receive the results from the Collector or via
   the Results repository.  They might visualise the data or identify
   which component or link is likely to be the cause of a fault or
   degradation.  This information could help the Controller decide what
   follow-up Measurement Task to perform in order to diagnose a fault.
   The data analysis tools also need to understand the Subscriber's
   service information, for example the broadband contract.

Eardley, et al.          Expires October 2, 2014                [Page 7]
Internet-Draft               LMAP Framework                   March 2014

                                                                 ^
                                                                 |
                                    Active    +-------------+    IPPM
               +---------------+  Measurement | Measurement |    Scope
               | Measurement   |<------------>|     Peer    |    |
               |   Agent       |   Traffic    +-------------+    v
      +------->|               |                                 ^
      |        +---------------+                                 |
      |              ^      |                                    |
      |  Instruction |      |  Report                            |
      |              |      +-----------------+                  |
      |              |                        |                  |
      |              |                        v                  LMAP
      |         +------------+             +------------+        Scope
      |         | Controller |             |  Collector |        |
      |         +------------+             +------------+        v
      |                ^   ^                       |             ^
      |                |   |                       |             |
      |                |   +----------+            |             |
      |                |              |            v             |
   +------------+   +----------+    +--------+    +----------+   |
   |Bootstrapper|   |Subscriber|--->|  data  |<---|repository|   Out
   +------------+   |parameter |    |analysis|    +----------+   of
                    |database  |    | tools  |                   Scope
                    +----------+    +--------+                   |
                                                                 |
                                                                 v

   Figure 1: Schematic of main elements of an LMAP-based
   measurement system
   (showing the elements in and out of the scope of the LMAP WG)

3.  Terminology

   This section defines terminology for LMAP.  Please note that defined
   terms are capitalized.

   Active Measurement Method (Task): A Measurement Method (Task) in
   which a Measurement Agent creates or receives Active Measurement
   Traffic, by coordinating with one or more other Measurement Agents or
   Measurement Peers using protocols outside LMAP's scope.

   Active Measurement Traffic: the packet(s) generated in order to
   execute an Active Measurement Task.

   Bootstrap: A process that integrates a Measurement Agent into a
   measurement system.

Eardley, et al.          Expires October 2, 2014                [Page 8]
Internet-Draft               LMAP Framework                   March 2014

   Capabilities: Information about the Measurement Methods that the MA
   can perform and the device hosting the MA, for example its interface
   type and speed, but not dynamic information.

   Channel: A bi-directional logical connection that is defined by a
   specific Controller and MA, or Collector and MA, plus associated
   security.

   Collector: A function that receives a Report from a Measurement
   Agent.

   Controller: A function that provides a Measurement Agent with its
   Instruction.

   Control Channel: a Channel between a Controller and a MA over which
   Instruction Messages and Capabilities and Failure information are
   sent.

   Control Protocol: The protocol delivering Instruction(s) from a
   Controller to a Measurement Agent.  It also delivers Failure
   Information and Capabilities Information from the Measurement Agent
   to the Controller.

   Cycle-ID: A tag that is sent by the Controller in an Instruction and
   echoed by the MA in its Report.  The same Cycle-ID is used by several
   MAs that use the same Measurement Method with the same Input
   Parameters.  Hence the Cycle-ID allows the Collector to easily
   identify Measurement Results that should be comparable.

   Data Model: The implementation of an Information Model in a
   particular data modelling language [RFC3444].

   Data Transfer Method: The process whereby: a Controller transfers
   information over a Control Channel to a MA; or a MA transfers
   information over a Control Channel to a Controller; or a MA transfers
   information over a Report Channel to a Collector; the generalisation
   of a Data Transfer Task.

   Data Transfer Task: The act consisting of the (single) operation of a
   Data Transfer Method at a particular time.

   Environmental Constraint: A parameter that is measured as part of the
   Measurement Task, its value determining whether the rest of the
   Measurement Task proceeds.

   Failure Information: Information about the MA's failure to action or
   execute an Instruction, whether concerning Measurement Tasks or
   Reporting.

Eardley, et al.          Expires October 2, 2014                [Page 9]
Internet-Draft               LMAP Framework                   March 2014

   Group-ID: An identifier of a group of MAs.

   Information Model: The protocol-neutral definition of the semantics
   of the Instructions, the Report, the status of the different elements
   of the measurement system as well of the events in the system
   [RFC3444].

   Input Parameter: A parameter whose value is left open by the
   Measurement Method and is set to a specific value in a Measurement
   Task.  Altering the value of an Input Parameter does not change the
   fundamental nature of the Measurement Method.

   Instruction: The description of Measurement Tasks for a MA to perform
   and the details of the Report for it to send.  It is the collective
   description of the Measurement Task configurations, the configuration
   of the Report Channel(s), the configuration of Data Transfer Tasks,
   the configuration of the Measurement Schedules, and the details of
   any suppression.

   Instruction Message: The message that carries an Instruction from a
   Controller to a Measurement Agent.

   Measurement Agent (MA): The function that receives Instruction
   Messages from a Controller and operates the Instruction by executing
   Measurement Tasks (using protocols outside LMAP's scope and perhaps
   in concert with one or more other Measurement Agents or Measurement
   Peers) and (if part of the Instruction) by reporting Measurement
   Results to a Collector or Collectors.

   Measurement Agent Identifier (MA-ID): a UUID [RFC4122] that
   identifies a particular MA and is configured as part of the
   Bootstrapping process.

   Measurement Method: The process for assessing the value of a Metric;
   the process of measuring some performance or reliability parameter
   associated with the transfer of traffic; the generalisation of a
   Measurement Task.

   Measurement Peer (MP): The function that assists a Measurement Agent
   with Measurement Tasks and does not have an interface to the
   Controller or Collector.

   Measurement Result: The output of a single Measurement Task (the
   value obtained for the parameter of interest or Metric).

   Measurement Schedule: The schedule for performing Measurement Tasks.

Eardley, et al.          Expires October 2, 2014               [Page 10]
Internet-Draft               LMAP Framework                   March 2014

   Measurement Task: The act that consistsof the single operation of the
   Measurement Method at a particular time and with all its Input
   Parameters set to specific values.

   Metric: The quantity related to the performance and reliability of
   the network that we'd like to know the value of, and that is
   carefully specified.

   Passive Measurement Method (Task): A Measurement Method (Task) in
   which a Measurement Agent observes existing traffic but does not
   inject Active Measurement Traffic.

   Report: The set of Measurement Results and other associated
   information (as defined by the Instruction).  The Report is sent by a
   Measurement Agent to a Collector.

   Report Channel: a communications channel between a MA and a
   Collector, which is defined by a specific MA, Collector, Report
   Schedule and associated security, and over which Reports are sent.

   Report Protocol: The protocol delivering Report(s) from a Measurement
   Agent to a Collector.

   Report Schedule: the schedule for sending Reports to a Collector.

   Subscriber: An entity (associated with one or more users) that is
   engaged in a subscription with a service provider.  The Subscriber is
   allowed to subscribe and un-subscribe services, and to register a
   user or a list of users authorized to enjoy these services.  [Q1741].
   Both the Subscriber and service provider are allowed to set the
   limits relative to the use that associated users make of subscribed
   services.

   Suppression: the temporary cessation of Active Measurement Tasks.

4.  Constraints

   The LMAP framework makes some important assumptions, which constrain
   the scope of the work to be done.

4.1.  Measurement system is under the direction of a single organisation

   In the LMAP framework, the measurement system is under the direction
   of a single organisation that is responsible for any impact that
   measurements have on a user's quality of experience and privacy.
   Clear responsibility is critical given that a misbehaving large-scale
   measurement system could potentially harm user experience, user
   privacy and network security.

Eardley, et al.          Expires October 2, 2014               [Page 11]
Internet-Draft               LMAP Framework                   March 2014

   However, the components of an LMAP measurement system can be deployed
   in administrative domains that are not owned by the measuring
   organisation.  Thus, the system of functions deployed by a single
   organisation constitutes a single LMAP domain which may span
   ownership or other administrative boundaries.

4.2.  Each MA may only have a single Controller at any point in time

   A MA is instructed by one Controller and is in one measurement
   system.  The constraint avoids different Controllers giving a MA
   conflicting instructions and so means that the MA does not have to
   manage contention between multiple Measurement (or Report) Schedules.
   This simplifies the design of MAs (critical for a large-scale
   infrastructure) and allows a Measurement Schedule to be tested on
   specific types of MA before deployment to ensure that the end user
   experience is not impacted (due to CPU, memory or broadband-product
   constraints).

   An operator may have several Controllers, perhaps with a Controller
   for different types of MA (home gateways, tablets) or location
   (Ipswich, Edinburgh).

5.  LMAP Protocol Model

   A protocol model [RFC4101] presents an architectural model for how
   the protocol operates and needs to answer three basic questions:

   1.  What problem is the protocol trying to achieve?

   2.  What messages are being transmitted and what do they mean?

   3.  What are the important, but unobvious, features of the protocol?

   An LMAP system goes through the following phases:

   o  a bootstrapping process before the MA can take part in the other
      three phases

   o  a Control Protocol, which delivers an Instruction from a
      Controller to a MA, detailing what Measurement Tasks the MA should
      perform and when, and how it should report the Measurement Results

   o  the actual Measurement Tasks, which measure some performance or
      reliability parameter(s) associated with the transfer of packets.
      The LMAP WG does not define Measurement Methods, however the IPPM
      WG does.

Eardley, et al.          Expires October 2, 2014               [Page 12]
Internet-Draft               LMAP Framework                   March 2014

   o  a Report Protocol, which delivers a Report from the MA to a
      Collector.  The Report contains the Measurement Results.

   The diagrams show the various LMAP messages and usesthe following
   convention:

   o  (optional): indicated by round brackets

   o  [potentially repeated]: indicated by square brackets

   The protocol model is closely related to the Information Model
   [I-D.burbridge-lmap-information-model], which is the abstract
   definition of the information carried by the protocol model.  The
   purpose of both is to provide a protocol and device independent view,
   which can be implemented via specific protocols.  The LMAP WG will
   define a specific Control Protocol and Report Protocol, but others
   could be defined by other standards bodies or be proprietary.
   However it is important that they all implement the same Information
   Model and protocol model, in order to ease the definition, operation
   and interoperability of large-scale measurement systems.

5.1.  Bootstrapping process

   The primary purpose of bootstrapping is to enable a MA to be
   integrated into a measurement system.  The MA retrieves information
   about itself (like its identity in the measurement system) and about
   the Controller, the Controller learns information about the MA, and
   they learn about security information to communicate (such as
   certificates and credentials).

   Whilst the LMAP WG considers the bootstrapping process, it is out of
   scope to define a bootstrap mechanism, as it depends on the type of
   device and access.

   As a result of the bootstrapping process the MA learns the following
   information:

   o  its identifier, MA-ID

   o  (optionally) a Group-ID.  A Group-ID would be shared by several
      MAs and could be useful for privacy reasons, for instance to
      hinder tracking of a mobile device

   o  the Control Channel, which is defined by:

      *  the address of the Controller (such as its FQDN (Fully
         Qualified Domain Name) [RFC1035])

Eardley, et al.          Expires October 2, 2014               [Page 13]
Internet-Draft               LMAP Framework                   March 2014

      *  security information (for example to enable the MA to decrypt
         the Instruction Message and encrypt messages sent to the
         Controller)

      *  the name of this Control Channel

   The details of the bootstrapping process are device /access specific.
   For example, the information could be in the firmware, manually
   configured or transferred via a protocol like TR-069.  There may be a
   multi-stage process where the MA contacts the device at a 'hard-
   coded' address, which replies with the boostrapping information.

5.2.  Control Protocol

   The primary purpose of the Control Protocol is to allow the
   Controller to configure a Measurement Agent with an Instruction about
   what Measurement Tasks to do, when to do them, and how to report the
   Measurement Results (Section 5.2.1).  The Measurement Agent then acts
   on the Instruction autonomously.  The Control Protocol also enables
   the MA to inform the Controller about its Capabilities and any
   Failures (Section 5.2.2).

5.2.1.  Instruction

   The Instruction is the description of the Measurement Tasks for a
   Measurement Agent to do and the details of the Measurement Reports
   for it to send.  In order to update the Instruction the Controller
   uses a Data Transfer Task to send an Instruction Message over the
   Control Channel.

+-----------------+                                      +-------------+
|                 |                                      | Measurement |
|  Controller     |======================================|  Agent      |
+-----------------+                                      +-------------+

Instruction:                            ->
[(Measurement Task configuration(
   [Input Parameter],
   (interface),
   (Cycle-ID))),
 (Report Channel),
 (Data Transfer Task),
 (Measurement Schedule),
 (Suppression information)]
                                         <-          Response(details)

   The Instruction defines the following:

Eardley, et al.          Expires October 2, 2014               [Page 14]
Internet-Draft               LMAP Framework                   March 2014

   o  the Measurement Task configurations, each of which needs:

      *  the Measurement Method, specified as a URN to a registry entry.
         The registry could be defined by the IETF
         [I-D.manyfolks-ippm-metric-registry], locally by the operator
         of the measurement system or perhaps by another standards
         organisation.

      *  any Input Parameters that need to be set for the Measurement
         Method, such as the address of the Measurement Peer (or other
         Measurement Agent) that are involved in an Active Measurement
         Task

      *  if the device with the MA has multiple interfaces, then the
         interface to use (if not defined, then the default interface is
         used)

      *  optionally, a Cycle-ID (a tag that may help the data analysis
         tools identify Measurement Results that should be comparable)

      *  a name for this Measurement Task configuration

   o  configuration of the Report Channels, each of which needs:

      *  the address of the Collector, for instance its URL

      *  security for this Report Channel, for example the X.509
         certificate

      *  a name for this Report Channel

   o  configuration of the Data Transfer Tasks, each of which needs:

      *  the name of the Channel to use

      *  the timing of when to operate this Data Transfer Task

      *  whether to include the MA-ID &/or Group-ID in a Measurement
         Report

      *  a name for this Data Transfer Task

      A Data Transfer Task may concern the reporting of Measurement
      Results (when the timing could be every hour or immediately, for
      instance).  Alternatively, a Data Transfer Task may concern the MA
      informing the Controller about its Capabilities or any Failures.

   o  configuration of the Measurement Schedules, each of which needs:

Eardley, et al.          Expires October 2, 2014               [Page 15]
Internet-Draft               LMAP Framework                   March 2014

      *  the name of one or several Measurement Task configurations

      *  the timing of when the Measurement Tasks are to be performed.
         Possible types of timing are periodic, calendar-based periodic,
         one-off immediate and one-off at a future time

      *  the name of a Data Transfer Task or Tasks on which to report
         the Measurement Results

      *  a name for this Measurement Schedule

   o  Suppression information, if any (see Section 5.2.1.1)

   A single Instruction Message may contain some or all of the above
   parts.  The finest level of granularity possible in an Instruction
   Message is determined by the implementation and operation of the
   Control Protocol.  For example, a single Instruction Message may be
   able to add or update an individual Measurement Schedule - or it may
   only be able to update the complete set of Measurement Schedules; a
   single Instruction Message may be able to update both Measurement
   Schedules and Measurement Task configurations - or only one at a
   time; and so on.

   The MA informs the Controller that it has successfully understood the
   Instruction Message, or that it cannot action the Instruction - for
   example, if it doesn't include a parameter that is mandatory for the
   requested Measurement Method, or it is missing details of the target
   Collector.

   The Instruction Message instructs the MA; the Control Protocol does
   not allow the MA to negotiate, as this would add complexity to the
   MA, Controller and Control Protocol for little benefit.

5.2.1.1.  Suppression

   The Instruction may include Suppression information.  Suppression is
   used if the measurement system wants to eliminate inessential
   traffic, because there is some unexpected network issue for example.
   By default, Suppression means that the MA does not begin any new
   Active Measurement Task.  The impact on other Measurement Tasks is
   not defined by LMAP; since they do not involve the MA creating any
   Active Measurement Traffic there is no need to suppress them, however
   it may be simpler for an implementation to do so.  Also, by default
   Suppression starts immediately and continues until an un-suppress
   message is received.  Optionally the Suppression information may
   include:

Eardley, et al.          Expires October 2, 2014               [Page 16]
Internet-Draft               LMAP Framework                   March 2014

   o  a set of Measurement Tasks to suppress; the others are not
      suppressed.  For example, this could be useful if a particular
      Measurement Task is overloading a Measurement Peer.

   o  a set of Measurement Schedules to suppress; the others are not
      suppressed.  For example, suppose the measurement system has
      defined two Schedules, one with the most critical Measurement
      Tasks and the other with less critical ones that create a lot of
      Active Measurement Traffic, then it may only want to suppress the
      second.

   o  a start time, at which suppression begins

   o  an end time, at which suppression ends

   o  that the MA should end its on-going Active Measurement Task(s).

   Note that Suppression is not intended to permanently stop a
   Measurement Task (instead, the Controller should send a new
   Measurement Schedule), nor to permanently disable a MA (instead, some
   kind of management action is suggested).

   +-----------------+                                   +-------------+
   |                 |                                   | Measurement |
   |  Controller     |===================================|  Agent      |
   +-----------------+                                   +-------------+

   Suppress:
   [(Measurement Task),                     ->
    (Measurement Schedule),
    start time,
    end time,
    on-going suppressed?]

   Un-suppress                              ->

5.2.2.  Capabilities and Failure information

   The Control Protocol also enables the MA to inform the Controller
   about various information, such as its Capabilities and any Failures,
   by the MA operating a Data Transfer Task.  It is also possible that a
   device-specific mechanism beyond the scope of LMAP is used.

   Capabilities are information about the MA that the Controller needs
   to know in order to correctly instruct the MA, such as:

   o  the Measurement Methods that the MA supports

Eardley, et al.          Expires October 2, 2014               [Page 17]
Internet-Draft               LMAP Framework                   March 2014

   o  the interfaces that the MA has

   o  the version of the MA

   o  the version of the hardware, firmware or software of the device
      with the MA

   o  but not dynamic information like the currently unused CPU, memory
      or battery life of the device with the MA.

   The MA could do this in response to a request from the Controller
   (for example, if the Controller forgets what the MA can do or
   otherwise wants to resynchronize what it knows about the MA) or on
   its own initiative (for example when the MA first communicates with a
   Controller or if it becomes capable of a new Measurement Method).
   Another example of the latter case is if the device with the MA re-
   boots, then the MA should notify its Controller in case its
   Instruction needs to be updated; to avoid a "mass calling event"
   after a widespread power restoration affecting many MAs, it is
   sensible for an MA to pause for a random delay, perhaps in the range
   of one minute or so.

   Failure information is sent on the initiative of the MA and concerns
   why the MA has been unable to execute a Measurement Task or Data
   Transfer Task, for example:

   o  the Measurement Task failed to run properly because the MA
      (unexpectedly) has no spare CPU cycles

   o  the MA failed record the Measurement Results because it
      (unexpectedly) is out of spare memory

   o  a Data Transfer Task failed to deliver Measurement Results because
      the Collector (unexpectedly) is not responding

   o  but not if a Measurement Task correctly doesn't start.  For
      example, the first step of some Measurement Methods is for the MA
      to check there is no cross-traffic.

   Logging information is sent by the MA in response to a request from
   the Controller; it concerns how the MA is operating and may help
   debugging, for example:

   o  the last time the MA ran a Measurement Task

   o  the last time the MA sent a Measurement Report

   o  the last time the MA received an Instruction Message

Eardley, et al.          Expires October 2, 2014               [Page 18]
Internet-Draft               LMAP Framework                   March 2014

   o  whether the MA is currently Suppressing Measurement Tasks

   .

 +-----------------+                                   +-------------+
 |                 |                                   | Measurement |
 |  Controller     |===================================|  Agent      |
 +-----------------+                                   +-------------+

 (Capabilities request)                   ->
                                          <-         Capabilities

                                          <-         Failure Information
                                                     [reason]

 Logging request                          ->
                                          <-         Logging Information
                                                     [details]

5.3.  Operation of Measurement Tasks

   The LMAP WG is neutral to what the actual Measurement Task is.  It
   does not define Measurement Methods, however the IPPM WG does.

   The MA carries out the Measurement Tasks as instructed, unless it
   gets an updated Instruction.  The MA acts autonomously, in terms of
   operation of the Measurement Tasks and reporting of the Results; it
   doesn't do a 'safety check' with the Controller to ask whether it
   should still continue with the requested Measurement Tasks.

5.3.1.  Starting and Stopping Measurement Tasks

   The WG does not define a generic start and stop process, since the
   correct approach depends on the particular Measurement Task; the
   details are defined as part of each Measurement Method.  This section
   provides some general hints.  The MA does not inform the Controller
   about Measurement Tasks starting and stopping.

   Before sending Active Measurement Traffic the MA may run a pre-check.
   Action could include:

   o  the MA checking that there is no cross-traffic.  In other words, a
      check that the end-user isn't already sending traffic;

   o  the MA checking with the Measurement Peer (or other Measurement
      Agent involved in the Measurement Task) that it can handle a new

Eardley, et al.          Expires October 2, 2014               [Page 19]
Internet-Draft               LMAP Framework                   March 2014

      Measurement Task (in case, for example, the Measurement Peer is
      already handling many Measurement Tasks with other MAs);

   o  the first part of the Measurement Task consisting of traffic that
      probes the path to make sure it isn't overloaded;

   o  the first part of the Measurement Task checking that the device
      with the MA has enough resources to execute the Measurement Task
      reliably.  Note that the designer of the measurement system should
      ensure that the device's capabilities are normally sufficient to
      comfortably operate the Measurement Tasks.

   It is possible that similar checks continue during the Measurement
   Task, especially one that is long-running and/or creates a lot of
   Active Measurement Traffic, and might lead to it being abandoned
   whilst in-progress.  A Measurement Task could also be abandoned in
   response to a "suppress" message (see Section 5.2.1).  Action could
   include:

   o  For 'upload' tests, the MA not sending traffic

   o  For 'download' tests, the MA closing the TCP connection or sending
      a TWAMP Stop control message [RFC5357].

   The Controller may want a MA to run the same Measurement Task
   indefinitely (for example, "run the 'upload speed' Measurement Task
   once an hour until further notice").  To avoid the MA generating
   traffic forever after a Controller has permanently failed, it is
   suggested that the Measurement Schedule includes a time limit ("run
   the 'upload speed' Measurement Task once an hour for the next 30
   days") and that the Measurement Schedule is updated regularly (say,
   every 10 days).

5.3.2.  Overlapping Measurement Tasks

   It is possible that a MA starts a new Measurement Task before another
   Measurement Task has completed.  This may be intentional (the way
   that the measurement system has designed the Measurement Schedules),
   but it could also be unintentional - for instance, if a Measurement
   Task has a 'wait for X' step which pauses for an unexpectedly long
   time.  The operator of the measurement system can handle (or not)
   overlapping Measurement Tasks in any way they choose - it is a policy
   or implementation issue and not the concern of LMAP.  Some possible
   approaches are: to configure the MA not to begin the second
   Measurement Task; to start the second Measurement Task as usual; for
   the action to be an Input Parameter of the Measurement Task; and so
   on.

Eardley, et al.          Expires October 2, 2014               [Page 20]
Internet-Draft               LMAP Framework                   March 2014

   It is likely to be important to include in the Measurement Report the
   fact that the Measurement Task overlapped with another.

5.4.  Report Protocol

   The primary purpose of the Report Protocol is to allow a Measurement
   Agent to report its Measurement Results to a Collector, along with
   the context in which they were obtained.

 +-----------------+                                   +-------------+
 |                 |                                   | Measurement |
 |   Collector     |===================================|  Agent      |
 +-----------------+                                   +-------------+

                                    <-    Report:
                                                  [MA-ID &/or Group-ID],
                                                    [Measurement Result
                                          [details of Measurement Task]]
 ACK                                ->

   The Report contains:

   o  the MA-ID or a Group-ID (to anonymise results)

   o  the actual Measurement Results, including the time they were
      measured

   o  the details of the Measurement Task (to avoid the Collector having
      to ask the Controller for this information later)

   o  perhaps the Subscriber's service parameters (see Section 5.4.1).

   The MA sends Reports as defined by the Data Transfer Task in the
   Controller's Instruction.  It is possible that the Instruction tells
   the MA to report the same Results to more than one Collector, or to
   report a different subset of Results to different Collectors.  It is
   also possible that a Measurement Task may create two (or more)
   Measurement Results, which could be reported differently (for
   example, one Result could be reported periodically, whilst the second
   Result could be an alarm that is created as soon as the measured
   value of the Metric crosses a threshold and that is reported
   immediately).

   Optionally, a Report is not sent when there are no Measurement
   Results.

Eardley, et al.          Expires October 2, 2014               [Page 21]
Internet-Draft               LMAP Framework                   March 2014

   In the initial LMAP Information Model and Report Protocol, for
   simplicity we assume that all Measurement Results are reported as-is,
   but allow extensibility so that a measurement system (or perhaps a
   second phase of LMAP) could allow a MA to:

   o  label, or perhaps not include, Measurement Results impacted by,
      for instance, cross-traffic or the Measurement Peer (or other
      Measurment Agent) being busy

   o  label Measurement Results obtained by a Measurement Task that
      overlapped with another

   o  not report the Measurement Results if the MA believes that they
      are invalid

   o  detail when Suppression started and ended

5.4.1.  Reporting of Subsriber's service parameters

   The Subscriber's service parameters are information about his/her
   broadband contract, line rate and so on.  Such information is likely
   to be needed to help analyse the Measurement Results, for example to
   help decide whether the measured download speed is reasonable.

   The information could be transferred directly from the Subscriber
   parameter database to the data analysis tools.  It may also be
   possible to transfer the information via the MA.  How (and if) the MA
   knows such information is likely to depend on the device type.  The
   MA could either include the information in a Measurement Report or
   run a separate Data Transfer Task.  All such considerations are out
   of scope of LMAP.

5.5.  Operation of LMAP over the underlying transport protocol

   The above sections have described LMAP's protocol model.  As part of
   the design of the Control and Report Protocols, the LMAP working
   group will specify operation over an existing protocol, to be
   selected, for example REST-style HTTP(S).  It is also possible that a
   different choice is made for the Control and Report Protocols, for
   example NETCONF-YANG and IPFIX respectively.

   From an LMAP perspective, the Controller needs to know that the MA
   has received the Instruction Message, or at least that it needs to be
   re-sent as it may have failed to be delivered.  Similarly the MA
   needs to know about the delivery of Capabilities and Failure
   information to the Controller and Reports to the Collector.  How this
   is done depends on the design of the Control and Report Protocols and
   the underlying transport protocol.

Eardley, et al.          Expires October 2, 2014               [Page 22]
Internet-Draft               LMAP Framework                   March 2014

   For the Control Protocol, the underlying transport protocol could be:

   o  a 'push' protocol (that is, from the Controller to the MA)

   o  a multicast protocol (from the Controller to a group of MAs)

   o  a 'pull' protocol.  The MA periodically checks with Controller if
      the Instruction has changed and pulls a new Instruction if
      necessary.  A pull protocol seems attractive for a MA behind a NAT
      (as is typical for a MA on an end-user's device), so that it can
      initiate the communications.  A pull mechanism is likely to
      require the MA to be configured with how frequently it should
      check in with the Controller, and perhaps what it should do if the
      Controller is unreachable after a certain number of attempts.

   o  a hybrid protocol.  In addition to a pull protocol, the Controller
      can also push an alert to the MA that it should immediately pull a
      new Instruction.

   For the Report Protocol, the underlying transport protocol could be:

   o  a 'push' protocol (that is, from the MA to the Collector)

   o  perhaps supplemented by the ability for the Collector to 'pull'
      Measurement Results from a MA.

5.6.  Items beyond the scope of the LMAP Protocol Model

   There are several potential interactions between LMAP elements that
   are out of scope of definition by the LMAP WG:

   1.  It does not define a coordination process between MAs.  Whilst a
       measurement system may define coordinated Measurement Schedules
       across its various MAs, there is no direct coordination between
       MAs.

   2.  It does not define interactions between the Collector and
       Controller.  It is quite likely that there will be such
       interactions, optionally intermediated by the data analysis
       tools.  For example, if there is an "interesting" Measurement
       Result then the measurement system may want to trigger extra
       Measurement Tasks that explore the potential cause in more
       detail; or if the Collector unexpectedly does not hear from a MA,
       then the measurement system may want to trigger the Controller to
       send a fresh Instruction Message to the MA.

   3.  It does not define coordination between different measurement
       systems.  For example, it does not define the interaction of a MA

Eardley, et al.          Expires October 2, 2014               [Page 23]
Internet-Draft               LMAP Framework                   March 2014

       in one measurement system with a Controller or Collector in a
       different measurement system.  Whilst it is likely that the
       Control and Report Protocols could be re-used or adapted for this
       scenario, any form of coordination between different
       organisations involves difficult commercial and technical issues
       and so, given the novelty of large-scale measurement efforts, any
       form of inter-organisation coordination is outside the scope of
       the LMAP WG.  Note that a single MA is instructed by a single
       Controller and is only in one measurement system.

       *  An interesting scenario is where a home contains two
          independent MAs, for example one controlled by a regulator and
          one controlled by an ISP.  Then the Active Measurement Traffic
          of one MA is treated by the other MA just like any other end-
          user traffic.

   4.  It does not consider how to prevent a malicious party "gaming the
       system".  For example, where a regulator is running a measurement
       system in order to benchmark operators, a malicious operator
       could try to identify the broadband lines that the regulator was
       measuring and prioritise that traffic.  It is assumed this is a
       policy issue and would be dealt with through a code of conduct
       for instance.

   5.  It does not define how to analyse Measurement Results, including
       how to interpret missing Results.

   6.  It does not specifically define a end-user-controlled measurement
       system, see sub-section 5.6.1.

5.6.1.  End-user-controlled measurement system

   The WG concentrates on the cases where an ISP or a regulator runs the
   measurement system.  However, we expect that LMAP functionality will
   also be used in the context of an end-user-controlled measurement
   system.  There are at least two ways this could happen (they have
   various pros and cons):

   1.  an end-user could somehow request the ISP- (or regulator-) run
       measurement system to test his/her line.  The ISP (or regulator)
       Controller would then send an Instruction to the MA in the usual
       LMAP way.  Note that a user can't directly initiate a Measurement
       Task on an ISP- (or regulator-) controlled MA.

   2.  an end-user could deploy their own measurement system, with their
       own MA, Controller and Collector.  For example, the user could
       implement all three functions onto the same end-user-owned end
       device, perhaps by downloading the functions from the ISP or

Eardley, et al.          Expires October 2, 2014               [Page 24]
Internet-Draft               LMAP Framework                   March 2014

       regulator.  Then the LMAP Control and Report Protocols do not
       need to be used, but using LMAP's Information Model would still
       be beneficial.  The Measurement Peer (or other MA involved in the
       Measurement Task) could be in the home gateway or outside the
       home network; in the latter case the Measurement Peer is highly
       likely to be run by a different organisation, which raises extra
       privacy considerations.

   In both cases there will be some way for the end-user to initiate the
   Measurement Task(s).  The mechanism is out-of-scope of the LMAP WG,
   but could include the user clicking a button on a GUI or sending a
   text message.  Presumably the user will also be able to see the
   Measurement Results, perhaps summarised on a webpage.  It is
   suggested that these interfaces conform to the LMAP guidance on
   privacy in Section 8.

6.  Deployment considerations

   The Appendix has some examples of possible deployment arrangements of
   Measurement Agents and Peers.

6.1.  Controller and the measurement system

   The Controller should understand both the MA's LMAP Capabilities (for
   instance what Measurement Methods it can perform) and about the MA's
   other capabilities like processing power and memory.  This allows the
   Controller to make sure that the Measurement Schedule of Measurement
   Tasks and the Reporting Schedule are sensible for each MA that it
   Instructs.

   An Instruction is likely to include several Measurement Tasks.
   Typically these run at different times, but it is also possible for
   them to run at the same time.  Some Tasks may be compatible, in that
   they do not affect each other's Results, whilst with others great
   care would need to be taken.

   The Controller should ensure that the Active Measurement Tasks do not
   have an adverse effect on the end user.  Typically Tasks, especially
   those that generate a substantial amount of traffic, will include a
   pre-check that the user isn't already sending traffic (Section 5.3).
   Another consideration is whether Active Measurement Traffic will
   impact a Subscriber's bill or traffic cap; if it will, then the
   measurement system may need to compensate the Subscriber, for
   instance.

   The different elements of the Instruction can be updated
   independently.  For example, the Measurement Tasks could be
   configured with different Input Parameters whilst keeping the same

Eardley, et al.          Expires October 2, 2014               [Page 25]
Internet-Draft               LMAP Framework                   March 2014

   Measurement Schedule.  In general this should not create any issues,
   since Measurement Methods should be defined so their fundamental
   nature does not change for a new value of Input Parameter.  There
   could be a problem if, for example, a Measurement Task involving a
   1kB file upload could be changed into a 1GB file upload.

   A measurement system may have multiple Controllers (but note the
   overriding principle that a single MA is instructed by a single
   Controller at any point in time (Section 4.2)).  For example, there
   could be different Controllers for different types of MA (home
   gateways, tablets) or locations (Ipswich, Edinburgh), for load
   balancing or to cope with failure of one Controller.

   The measurement system also needs to consider carefully how to
   interpret missing Results; for example, if the missing Results are
   ignored and the lack of a Report is caused by its broadband being
   broken, then the estimate of overall performance, averaged across all
   MAs, would be too optimistic.

6.2.  Measurement Agent

   The Measurement Agent could take a number of forms: a dedicated
   probe, software on a PC, embedded into an appliance, or even embedded
   into a gateway.  A single site (home, branch office etc.) that is
   participating in a measurement could make use of one or multiple
   Measurement Agents or Measurement Peers in a single measurement.

   The Measurement Agent could be deployed in a variety of locations.
   Not all deployment locations are available to every kind of
   Measurement Agent.  There are also a variety of limitations and
   trade-offs depending on the final placement.  The next sections
   outline some of the locations a Measurement Agent may be deployed.
   This is not an exhaustive list and combinations may also apply.

6.2.1.  Measurement Agent on a networked device

   A MA may be embedded on a device that is directly connected to the
   network, such as a MA on a smartphone.

6.2.2.  Measurement Agent embedded in site gateway

   A Measurement Agent embedded with the site gateway, for example a
   home router or the edge router of a branch office in a managed
   service environment, is one of better places the Measurement Agent
   could be deployed.  All site-to-ISP traffic would traverse through
   the gateway and passive measurements could easily be performed.
   Similarly, due to this user traffic visibility, an Active Measurement
   Task could be rescheduled so as not to compete with user traffic.

Eardley, et al.          Expires October 2, 2014               [Page 26]
Internet-Draft               LMAP Framework                   March 2014

   Generally NAT and firewall services are built into the gateway,
   allowing the Measurement Agent the option to offer its Controller-
   facing management interface outside of the NAT/firewall.  This
   placement of the management interface allows the Controller to
   unilaterally contact the Measurement Agent for instructions.
   However, if the site gateway is owned and operated by the service
   provider, the Measurement Agent will generally not be directly
   available for over the top providers, the regulator, end users or
   enterprises.

6.2.3.  Measurement Agent embedded behind site NAT /Firewall

   The Measurement Agent could also be embedded behind a NAT, a
   firewall, or both.  In this case the Controller may not be able to
   unilaterally contact the Measurement Agent unless either static port
   forwarding configuration or firewall pin holing is configured.  For
   the former, protocols such as PCP [RFC6887], TR-069 [TR-069]or UPnP
   [UPnP]could be used.  For the latter, the Measurement Agent could
   send keepalives towards the Controller to prop open the firewall (and
   perhaps use these also as a network reachability test).

6.2.4.  Multi-homed Measurement Agent

   If the device with the Measurement Agent is single homed then there
   is no confusion about what interface to measure.  Similarly, if the
   MA is at the gateway and the gateway only has a single WAN-side and a
   single LAN-side interface, there is little confusion - for an Active
   Measurement Task, the location of the other MA or Measurement Peer
   determines whether the WAN or LAN is measured.

   However, the device with the Measurement Agent may be multi-homed.
   For example, a home or campus may be connected to multiple broadband
   ISPs, such as a wired and wireless broadband provider, perhaps for
   redundancy or load- sharing.  It may also be helpful to think of dual
   stack IPv4 and IPv6 broadband devices as multi-homed.  More
   generally, Section 3.2 of [I-D.ietf-homenet-arch] describes dual-
   stack and multi-homing topologies that might be encountered in a home
   network, [RFC6419] provides the current practices of multi-interfaces
   hosts, and the Multiple Interfaces (mif) working group covers cases
   where hosts are either directly attached to multiple networks
   (physical or virtual) or indirectly (multiple default routers, etc.).
   In these cases, there needs to be clarity on which network
   connectivity option is being measured.

   One possibility is to have a Measurement Agent per interface.  Then
   the Controller's choice of MA determines which interface is measured.
   However, if a MA can measure any of the interfaces, then the
   Controller defines in the Instruction which interface the MA should

Eardley, et al.          Expires October 2, 2014               [Page 27]
Internet-Draft               LMAP Framework                   March 2014

   use for a Measurement Task; if the choice of interface is not defined
   then the MA uses the default one.  Explicit definition is preferred
   if the measurement system wants to measure the performance of a
   particular network, whereas using the default is better if the
   measurement system wants to include the impact of the MA's interface
   selection algorithm.  In any case, the Measurement Result should
   include the network that was measured.

6.3.  Measurement Peer

   A Measurement Peer participates in Active Measurement Tasks.  It may
   have specific functionality to enable it to participate in a
   particular Measurement Method.  On the other hand, other Measurement
   Methods may require no special functionality, for example if the
   Measurement Agent sends a ping to example.com then the server at
   example.com plays the role of a Measurement Peer.

   A device may participate in some Measurement Tasks as a Measurement
   Agent and in others as a Measurement Peer.

   Measurement schedules should account for limited resources in a
   Measurement Peer when instructing a MA to execute measurements with a
   Measurement Peer.  In some measurement protocols, such as [RFC4656]
   and [RFC5357], the Measurement Peer can reject a measurement session
   or refuse a control connection prior to setting-up a measurement
   session and so protect itself from resource exhaustion.  This is a
   valuable capability because the MP may be used by more than one
   organisation.

7.  Security considerations

   The security of the LMAP framework should protect the interests of
   the measurement operator(s), the network user(s) and other actors who
   could be impacted by a compromised measurement deployment.  The
   measurement system must secure the various components of the system
   from unauthorised access or corruption.  Much of the general advice
   contained in section 6 of [RFC4656] is applicable here.

   We assume that each Measurement Agent (MA) will receive its
   Instructions from a single organisation, which operates the
   Controller.  These Instructions must be authenticated (to ensure that
   they come from the trusted Controller), checked for integrity (to
   ensure no-one has tampered with them) and not vulnerable to replay
   attacks.  If a malicious party can gain control of the MA they can
   use it to launch DoS attacks at targets, reduce the end user's
   quality of experience and corrupt the Measurement Results that are
   reported to the Collector.  By altering the Measurement Tasks and/or
   the address that Results are reported to, they can also compromise

Eardley, et al.          Expires October 2, 2014               [Page 28]
Internet-Draft               LMAP Framework                   March 2014

   the confidentiality of the network user and the MA environment (such
   as information about the location of devices or their traffic).

   The process to upgrade the firmware in an MA is out-of-scope for this
   phase of LMAP development, similar to the protocol to bootstrap the
   MAs (as specified in the charter).  However, systems which provide
   remote upgrade must secure authorised access and integrity of the
   process.

   Reporting by the MA must also be secured to maintain confidentiality.
   The results must be encrypted such that only the authorised Collector
   can decrypt the results to prevent the leakage of confidential or
   private information.  In addition it must be authenticated that the
   results have come from the expected MA and that they have not been
   tampered with.  It must not be possible to fool a MA into injecting
   falsified data into the measurement platform or to corrupt the
   results of a real MA.  The results must also be held and processed
   securely after collection and analysis.  See section 8.5.2 below for
   additional considerations on stored data compromise, and section 8.6
   on potential mitigations for compromise.

   Since Collectors will be contacted repeatedly by MAs using the
   Collection Protocol to convey their recent results, a successful
   attack to exhaust the communication resources would prevent a
   critical operation: reporting.  Therefore, all LMAP Collectors should
   implement technical mechanisms to:

   o  limit the number of reporting connections from a single MA
      (simultaneous, and connections per unit time).

   o  limit the transmission rate from a single MA.

   o  limit the memory/storage consumed by a single MA's reports.

   o  efficiently reject reporting connections from unknown sources.

   o  separate resources if multiple authentication strengths are used,
      where the resources should be separated according to each class of
      strength.

   o  limit iteration counters to generate keys with both a lower and
      upper limit, to prevent an attacking system from requesting the
      maximum and causing the Controller to stall on the process (see
      section 6 of [RFC5357]).

   Many of the above considerations are applicable to Controllers using
   a "push" model, where the MA must contact the Controller because NAT

Eardley, et al.          Expires October 2, 2014               [Page 29]
Internet-Draft               LMAP Framework                   March 2014

   or other network aspect prevents Controllers from contacting MAs
   directly.

   Availability should also be considered.  While the loss of some MAs
   may not be considered critical, the unavailability of the Collector
   could mean that valuable business data or data critical to a
   regulatory process is lost.  Similarly, the unavailability of a
   Controller could mean that the MAs do not operate a correct
   Measurement Schedule.

   A malicious party could "game the system".  For example, where a
   regulator is running a measurement system in order to benchmark
   operators, an operator could try to identify the broadband lines that
   the regulator was measuring and prioritise that traffic.  This
   potential issue is currently handled by a code of conduct.  It is
   outside the scope of the LMAP WG to consider the issue.

8.  Privacy Considerations for LMAP

   The LMAP Working Group will consider privacy as a core requirement
   and will ensure that by default the Control and Report Protocols
   operate in a privacy-sensitive manner and that privacy features are
   well-defined.

   This section provides a set of privacy considerations for LMAP.  This
   section benefits greatly from the timely publication of [RFC6973].
   Privacy and security (Section 7) are related.  In some jurisdictions
   privacy is called data protection.

   We begin with a set of assumptions related to protecting the
   sensitive information of individuals and organisations participating
   in LMAP-orchestrated measurement and data collection.

8.1.  Categories of Entities with Information of Interest

   LMAP protocols need to protect the sensitive information of the
   following entities, including individuals and organisations who
   participate in measurement and collection of results.

   o  Individual Internet users: Persons who utilise Internet access
      services for communications tasks, according to the terms of
      service of a service agreement.  Such persons may be a service
      Subscriber, or have been given permission by the Subscriber to use
      the service.

   o  Internet service providers: Organisations who offer Internet
      access service subscriptions, and thus have access to sensitive
      information of individuals who choose to use the service.  These

Eardley, et al.          Expires October 2, 2014               [Page 30]
Internet-Draft               LMAP Framework                   March 2014

      organisations desire to protect their Subscribers and their own
      sensitive information which may be stored in the process of
      performing Measurement Tasks and collecting and Results.

   o  Regulators: Public authorities responsible for exercising
      supervision of the electronic communications sector, and which may
      have access to sensitive information of individuals who
      participate in a measurement campaign.  Similarly, regulators
      desire to protect the participants and their own sensitive
      information.

   o  Other LMAP system operators: Organisations who operate measurement
      systems or participate in measurements in some way.

   Although privacy is a protection extended to individuals, we include
   discussion of ISPs and other LMAP system operators in this section.
   These organisations have sensitive information involved in the LMAP
   system, and many of the same dangers and mitigations are applicable.
   Further, the ISPs store information on their Subscribers beyond that
   used in the LMAP system (for instance billing information), and there
   should be a benefit in considering all the needs and potential
   solutions coherently.

8.2.  Examples of Sensitive Information

   This section gives examples of sensitive information which may be
   measured or stored in a measurement system, and which is to be kept
   private by default in the LMAP core protocols.

   Examples of Subscriber or authorised Internet user sensitive
   information:

   o  Sub-IP layer addresses and names (MAC address, base station ID,
      SSID)

   o  IP address in use

   o  Personal Identification (real name)

   o  Location (street address, city)

   o  Subscribed service parameters

   o  Contents of traffic (activity, DNS queries, destinations,
      equipment types, account info for other services, etc.)

   o  Status as a study volunteer and Schedule of (Active) Measurement
      Tasks

Eardley, et al.          Expires October 2, 2014               [Page 31]
Internet-Draft               LMAP Framework                   March 2014

   Examples of Internet Service Provider sensitive information:

   o  Measurement device identification (equipment ID and IP address)

   o  Measurement Instructions (choice of measurements)

   o  Measurement Results (some may be shared, others may be private)

   o  Measurement Schedule (exact times)

   o  Network topology (locations, connectivity, redundancy)

   o  Subscriber billing information, and any of the above Subscriber
      information known to the provider.

   o  Authentication credentials (such as certificates)

   Other organisations will have some combination of the lists above.
   The LMAP system would not typically expose all of the information
   above, but could expose a combination of items which could be
   correlated with other pieces collected by an attacker (as discussed
   in the section on Threats below).

8.3.  Key Distinction Between Active and Passive Measurement Tasks

   Passive and Active Measurement Tasks raise different privacy issues.

   Passive Measurement Tasks are conducted on a user's traffic, such
   that sensitive information is present and stored in the measurement
   system (however briefly this storage may be).  We note that some
   authorities make a distinction on time of storage, and information
   that is kept only temporarily to perform a communications function is
   not subject to regulation (for example, active queue management, deep
   packet inspection).  Passive Measurement Tasks could reveal all the
   websites a Subscriber visits and the applications and/or services
   they use.

   Active Measurement Tasks are conducted on traffic which is created
   specifically for the purpose.  Even if a user host generates Active
   Measurement Traffic, there is limited sensitive information about the
   Subscriber present and stored in the measurement system compared to
   the passive case, as follows:

   o  IP address in use (and possibly sub-IP addresses and names)

   o  Status as a study volunteer and Schedule of Active Measurement
      Tasks

Eardley, et al.          Expires October 2, 2014               [Page 32]
Internet-Draft               LMAP Framework                   March 2014

   On the other hand, for a service provider the sensitive information
   like Measurement Results is the same for Passive and Active
   Measurement Tasks.

   From the Subscriber perspective, both Active and Passive Measurement
   Tasks potentially expose the description of Internet access service
   and specific service parameters, such as subscribed rate and type of
   access.

8.4.  Privacy analysis of the Communications Models

   This section examines each of the protocol exchanges described at a
   high level in Section 5 and some example Measurement Tasks, and
   identifies specific sensitive information which must be secured
   during communication for each case.  With the protocol-related
   sensitive information identified, we can better consider the threats
   described in the following section.

   From the privacy perspective, all entities participating in LMAP
   protocols can be considered "observers" according to the definition
   in [RFC6973].  Their stored information potentially poses a threat to
   privacy, especially if one or more of these functional entities has
   been compromised.  Likewise, all devices on the paths used for
   control, reporting, and measurement are also observers.

8.4.1.  MA Bootstrapping

   Section 5.1 provides the communication model for the Bootstrapping
   process.

   Although the specification of mechanisms for Bootstrapping the MA are
   beyond the LMAP scope, designers should recognize that the
   Bootstrapping process is extremely powerful and could cause an MA to
   join a new or different LMAP system with a different Controller and
   Collector, or simply install new Measurement Methods (for example to
   passively record DNS queries).  A Bootstrap attack could result in a
   breach of the LMAP system with significant sensitive information
   exposure depending on the capabilities of the MA, so sufficient
   security protections are warranted.

   The Bootstrapping process provides sensitive information about the
   LMAP system and the organisation that operates it, such as

   o  Initial Controller IP address or FQDN

   o  Assigned Controller IP address or FQDN

   o  Security certificates and credentials

Eardley, et al.          Expires October 2, 2014               [Page 33]
Internet-Draft               LMAP Framework                   March 2014

   During the Bootstrap process, the MA receives its MA-ID which is a
   persistent pseudonym for the Subscriber in the case that the MA is
   located at a service demarcation point.  Thus, the MA-ID is
   considered sensitive information, because it could provide the link
   between Subscriber identification and Measurements Results.

   Also, the Bootstrap process could assign a Group-ID to the MA.  The
   specific definition of information represented in a Group-ID is to be
   determined, but several examples are envisaged including use as a
   pseudonym for a set of Subscribers, a class of service, an access
   technology, or other important categories.  Assignment of a Group-ID
   enables anonymisation sets to be formed on the basis of service type/
   grade/rates.  Thus, the mapping between Group-ID and MA-ID is
   considered sensitive information.

8.4.2.  Controller <-> Measurement Agent

   The high-level communication model for interactions between the LMAP
   Controller and Measurement Agent is illustrated in Section 5.2.  The
   primary purpose of this exchange is to authenticate and task a
   Measurement Agent with Measurement Instructions, which the
   Measurement Agent then acts on autonomously.

   Primarily IP addresses and pseudonyms (MA-ID, Group-ID) are exchanged
   with a capability request, then measurement-related information of
   interest such as the parameters, schedule, metrics, and IP addresses
   of measurement devices.  Thus, the measurement Instruction contains
   sensitive information which must be secured.  For example, the fact
   that an ISP is running additional measurements beyond the set
   reported externally is sensitive information, as are the additional
   Measurements Tasks themselves.  The Measurement Schedule is also
   sensitive, because an attacker intending to bias the results without
   being detected can use this information to great advantage.

   An organisation operating the Controller having no service
   relationship with a user who hosts the Measurement Agent *could* gain
   real-name mapping to a public IP address through user participation
   in an LMAP system (this applies to the Measurement Collection
   protocol, as well).

8.4.3.  Collector <-> Measurement Agent

   The high-level communication model for interactions between the
   Measurement Agent and Collector is illustrated in Section 5.4.  The
   primary purpose of this exchange is to authenticate and collect
   Measurement Results from a MA, which the MA has measured autonomously
   and stored.

Eardley, et al.          Expires October 2, 2014               [Page 34]
Internet-Draft               LMAP Framework                   March 2014

   The Measurement Results are the additional sensitive information
   included in the Collector-MA exchange.  Organisations collecting LMAP
   measurements have the responsibility for data control.  Thus, the
   Results and other information communicated in the Collector protocol
   must be secured.

8.4.4.  Measurement Peer <-> Measurement Agent

   Although the specification of the mechanisms for an Active
   Measurement Task is beyond the scope of LMAP, it raises potential
   privacy issues.  The high-level communications model below
   illustrates the various exchanges to execute Active Measurement Tasks
   and store the Results.

   We note the potential for additional observers in the figures below
   by indicating the possible presence of a NAT, which has additional
   significance to the protocols and direction of initiation.

   The various messages are optional, depending on the nature of the
   Active Measurement Task.  It may involve sending Active Measurement
   Traffic from the Measurement Peer to MA, MA to Measurement Peer, or
   both.

Eardley, et al.          Expires October 2, 2014               [Page 35]
Internet-Draft               LMAP Framework                   March 2014

    _________________                              _________________
   |                 |                            |                 |
   |Measurement Peer |=========== NAT ? ==========|Measurement Agent|
   |_________________|                            |_________________|

                                  <-              (Key Negotiation &
                                                  Encryption Setup)
   (Encrypted Channel             ->
   Established)
   (Announce capabilities         ->
   & status)
                                  <-              (Select capabilities)
   ACK                            ->
                                  <-              (Measurement Request
                                                 (MA+MP IPAddrs,set of
                                                   Metrics, Schedule))
   ACK                            ->

   Active Measurement Traffic     <>        Active Measurement Traffic
   (may/may not be encrypted)               (may/may not be encrypted)

                                  <-            (Stop Measurement Task)

   Measurement Results            ->
   (if applicable)
                                  <-               ACK, Close

   This exchange primarily exposes the IP addresses of measurement
   devices and the inference of measurement participation from such
   traffic.  There may be sensitive information on key points in a
   service provider's network included.  There may also be access to
   measurement-related information of interest such as the Metrics,
   Schedule, and intermediate results carried in the Active Measurement
   Traffic (usually a set of timestamps).

   If the Active Measurement Traffic is unencrypted, as found in many
   systems today, then both timing and limited results are open to on-
   path observers.

8.4.5.  Passive Measurement Agent

   Although the specification of the mechanisms for a Passive
   Measurement Task is beyond the scope of LMAP, it raises potential
   privacy issues.

   The high-level communications model below illustrates the collection
   of user information of interest with the Measurement Agent performing
   the monitoring and storage of the Results.  This particular exchange

Eardley, et al.          Expires October 2, 2014               [Page 36]
Internet-Draft               LMAP Framework                   March 2014

   is for passive measurement of DNS Response Time, which most
   frequently uses UDP transport.

    _________________                                      ____________
   |                 |                                    |            |
   |  DNS Server     |=========== NAT ? ==========*=======| User client|
   |_________________|                            ^       |____________|
                                            ______|_______
                                           |              |
                                           |  Measurement |
                                           |    Agent     |
                                           |______________|

                                  <-              Name Resolution Req
                                                 (MA+MP IPAddrs,
                                                  Desired Domain Name)
   Return Record                  ->

   This exchange primarily exposes the IP addresses of measurement
   devices and the intent to communicate with or access the services of
   "Domain Name".  There may be information on key points in a service
   provider's network, such as the address of one of its DNS servers.
   The Measurement Agent may be embedded in the user host, or it may be
   located in another device capable of observing user traffic.

   In principle, any of the user sensitive information of interest
   (listed above) can be collected and stored in the passive monitoring
   scenario and so must be secured.

   It would also be possible for a Measurement Agent to source the DNS
   query itself.  But then, as with any active measurement task, there
   are few privacy concerns.

8.4.6.  Storage and Reporting of Measurement Results

   Although the mechanisms for communicating results (beyond the initial
   Collector) are beyond the LMAP scope, there are potential privacy
   issues related to a single organisation's storage and reporting of
   Measurement Results.  Both storage and reporting functions can help
   to preserve privacy by implementing the mitigations described below.

8.5.  Threats

   This section indicates how each of the threats described in [RFC6973]
   apply to the LMAP entities and their communication and storage of
   "information of interest".

Eardley, et al.          Expires October 2, 2014               [Page 37]
Internet-Draft               LMAP Framework                   March 2014

8.5.1.  Surveillance

   Section 5.1.1 of [RFC6973] describes Surveillance as the "observation
   or monitoring of and individual's communications or activities."
   Hence all Passive Measurement Tasks are a form of surveillance, with
   inherent risks.

   Active Measurement Methods which avoid periods of user transmission
   indirectly produce a record of times when a subscriber or authorised
   user has used their network access service.

   Active Measurement Methods may also utilise and store a Subscriber's
   currently assigned IP address when conducting measurements that are
   relevant to a specific Subscriber.  Since the Measurement Results are
   time-stamped, they could provide a record of IP address assignments
   over time.

   Either of the above pieces of information could be useful in
   correlation and identification, described below.

8.5.2.  Stored Data Compromise

   Section 5.1.2 of [RFC6973] describes Stored Data Compromise as
   resulting from inadequate measures to secure stored data from
   unauthorised or inappropriate access.  For LMAP systems this includes
   deleting or modifying collected measurement records, as well as data
   theft.

   The primary LMAP entity subject to compromise is the repository,
   which stores the Measurement Results; extensive security and privacy
   threat mitigations are warranted.  The Collector and MA also store
   sensitive information temporarily, and need protection.  The
   communications between the local storage of the Collector and the
   repository is beyond the scope of the LMAP work at this time, though
   this communications channel will certainly need protection as well as
   the mass storage itself.

   The LMAP Controller may have direct access to storage of Subscriber
   information (location, billing, service parameters, etc.) and other
   information which the controlling organisation considers private, and
   again needs protection.

   Note that there is tension between the desire to store all raw
   results in the LMAP Collector (for reproduceability and custom
   analysis), and the need to protect the privacy of measurement
   participants.  Many of the compromise mitigations described in
   section 8.6 below are most efficient when deployed at the MA,
   therefore minimizing the risks with stored results.

Eardley, et al.          Expires October 2, 2014               [Page 38]
Internet-Draft               LMAP Framework                   March 2014

8.5.3.  Correlation and Identification

   Sections 5.2.1 and 5.2.2 of [RFC6973] describes Correlation as
   combining various pieces of information to obtain desired
   characteristics of an individual, and Identification as using this
   process to infer identity.

   The main risk is that the LMAP system could unwittingly provide a key
   piece of the correlation chain, starting with an unknown Subscriber's
   IP address and another piece of information.  For example, a
   Subscriber utilised Internet access from 2000 to 2310 UTC, because
   the Active Measurement Tasks were deferred, or sent a name resolution
   for www.example.com at 2300 UTC.

8.5.4.  Secondary Use and Disclosure

   Sections 5.2.3 and 5.2.4 of [RFC6973] describes Secondary Use as
   unauthorised utilisation of an individual's information for a purpose
   the individual did not intend, and Disclosure is when such
   information is revealed causing other's notions of the individual to
   change, or confidentiality to be violated.

   Passive Measurement Tasks are a form of Secondary Use, and the
   Subscribers' permission and the measured ISP's permission should be
   obtained beforehand.  Although user traffic is only indirectly
   involved, the Measurement Results from Active Measurement Tasks
   provide some limited information about the Subscriber/ISP and could
   be used for Secondary Uses.  For example, the use of the Results in
   unauthorised marketing campaigns would qualify as Secondary Use.

8.6.  Mitigations

   This section examines the mitigations listed in section 6 of
   [RFC6973] and their applicability to LMAP systems.  Note that each
   section in [RFC6973] identifies the threat categories that each
   technique mitigates.

8.6.1.  Data Minimisation

   Section 6.1 of [RFC6973] encourages collecting and storing the
   minimal information needed to perform a task.

   There are two levels of information needed for LMAP results to be
   useful for a specific task: troubleshooting and general results
   reporting.

   For general results, the results can be aggregated into large
   categories (the month of March, all subscribers West of the

Eardley, et al.          Expires October 2, 2014               [Page 39]
Internet-Draft               LMAP Framework                   March 2014

   Mississippi River).  In this case, all individual identifications
   (including IP address of the MA) can be excluded, and only relevant
   results are provided.  However, this implies a filtering process to
   reduce the information fields, because greater detail was needed to
   conduct the Measurement Tasks in the first place.

   For troubleshooting, so that a network operator or end user can
   identify a performance issue or failure, potentially all the network
   information (IP addresses, equipment IDs, location), Measurement
   Schedule, service configuration, Measurement Results, and other
   information may assist in the process.  This includes the information
   needed to conduct the Measurements Tasks, and represents a need where
   the maximum relevant information is desirable, therefore the greatest
   protections should be applied.

   We note that a user may give temporary permission for Passive
   Measurement Tasks to enable detailed troubleshooting, but withhold
   permission for them in general.  Here the greatest breadth of
   sensitive information is potentially exposed, and the maximum privacy
   protection must be provided.

   For MAs with access to the sensitive information of users (e.g.,
   within a home or a personal host/handset), it is desirable for the
   results collection to minimise the data reported, but also to balance
   this desire with the needs of troubleshooting when a service
   subscription exists between the user and organisation operating the
   measurements.

   For passive measurements where the MA reports flow information to the
   Collector, the Collector may perform pre-storage minimisation and
   other mitigations (below) to help preserve privacy.

8.6.2.  Anonymity

   Section 6.1.1 of [RFC6973] describes a way in which anonymity is
   achieved: "there must exist a set of individuals that appear to have
   the same attributes as the individual", defined as an "anonymity
   set".

   Experimental methods for anonymisation of user identifiable data
   applicable to Passive Measurement Methods have been identified in
   [RFC6235].  However, the findings of several of the same authors is
   that "there is increasing evidence that anonymisation applied to
   network trace or flow data on its own is insufficient for many data
   protection applications as in [Bur10]."

   Essentially, the details of passive measurement tasks can only be
   accessed by closed organisations, and unknown injection attacks are

Eardley, et al.          Expires October 2, 2014               [Page 40]
Internet-Draft               LMAP Framework                   March 2014

   always less expensive than the protections from them.  However, some
   forms of summary may protect the user's sensitive information
   sufficiently well, and so each Metric must be evaluated in the light
   of privacy.

   The methods in [RFC6235] could be applied more successfully in Active
   Measurement Methods, where there are protections from injection
   attack.  The successful attack would require breaking the integrity
   protection of the LMAP Reporting Protocol and injecting Measurement
   Results (known fingerprint, see section 3.2 of [RFC6973]) for
   inclusion with the shared and anonymised results, then fingerprinting
   those records to ascertain the anonymisation process.

   Beside anonymisation of measured Results for a specific user or
   provider, the value of sensitive information can be further diluted
   by summarising the results over many individuals or areas served by
   the provider.  There is an opportunity enabled by forming anonymity
   sets [RFC6973] based on the reference path measurement points in
   [I-D.ietf-ippm-lmap-path].  For example, all measurements from the
   Subscriber device can be identified as "mp000", instead of using the
   IP address or other device information.  The same anonymisation
   applies to the Internet Service Provider, where their Internet
   gateway would be referred to as "mp190".

8.6.3.  Pseudonymity

   Section 6.1.2 of [RFC6973] indicates that pseudonyms, or nicknames,
   are a possible mitigation to revealing one's true identity, since
   there is no requirement to use real names in almost all protocols.

   A pseudonym for a measurement device's IP address could be an LMAP-
   unique equipment ID.  However, this would likely be a permanent
   handle for the device, and long-term use weakens a pseudonym's power
   to obscure identity.

8.6.4.  Other Mitigations

   Data can be de-personalised by blurring it, for example by adding
   synthetic data, data-swapping, or perturbing the values in ways that
   can be reversed or corrected.

   Sections 6.2 and 6.3 of [RFC6973] describe User Participation and
   Security, respectively.

   Where LMAP measurements involve devices on the Subscriber's premises
   or Subscriber-owned equipment, it is essential to secure the
   Subscriber's permission with regard to the specific information that
   will be collected.  The informed consent of the Subscriber (and, if

Eardley, et al.          Expires October 2, 2014               [Page 41]
Internet-Draft               LMAP Framework                   March 2014

   different, the end user) is needed, including the specific purpose of
   the measurements.  The approval process could involve showing the
   Subscriber their measured information and results before instituting
   periodic collection, or before all instances of collection, with the
   option to cancel collection temporarily or permanently.

   It should also be clear who is legally responsible for data
   protection (privacy); in some jurisdictions this role is called the
   'data controller'.  It is good practice to time limit the storage of
   personal information.

   Although the details of verification would be impenetrable to most
   subscribers, the MA could be architected as an "app" with open
   source-code, pre-download and embedded terms of use and agreement on
   measurements, and protection from code modifications usually provided
   by the app-stores.  Further, the app itself could provide data
   reduction and temporary storage mitigations as appropriate and
   certified through code review.

   LMAP protocols, devices, and the information they store clearly need
   to be secure from unauthorised access.  This is the hand-off between
   privacy and security considerations (Section 7).  The Data Controller
   has the (legal) responsibility to maintain data protections described
   in the Subscriber's agreement and agreements with other
   organisations.

9.  IANA Considerations

   There are no IANA considerations in this memo.

10.  Appendix: Deployment examples

   In this section we describe some deployment scenarios that are
   feasible within the LMAP framework defined in this document.

   The LMAP framework defines two types of components involved in the
   actual measurement task, namely the Measurement Agent (MA) and the
   Measurement Peer (MP).  The fundamental difference conveyed in the
   definition of these terms is that the MA has a interface with the
   Controller/Collector while the MP does not.  The MP is broadly
   defined as a function that assists the MA in the Measurement Task but
   has no interface with the Controller/Collector.  There are many
   elements in the network that can fall into this broad definition of
   MP.  We believe that the MP terminology is useful to allow us to
   refer an element of the network that plays a role that is
   conceptually important to understand and describe the measurement
   task being performed.  We next illustrate these concepts by
   describing several deployment scenarios.

Eardley, et al.          Expires October 2, 2014               [Page 42]
Internet-Draft               LMAP Framework                   March 2014

   A very simple example of a Measurement Peer is a web server that the
   MA is downloading a web page from (such as www.example.com) in order
   to perform a speed test.  The web server is an MP and from its
   perspective, the MA is just another customer; the MP doesn't have a
   specific function for assisting measurements.  This is described in
   the figure A1.

                                                            ^
      +----------------+  Web Traffic +----------------+  IPPM
      |   Web Client   |<------------>| MP: Web Server |  Scope
      |                |              +----------------+    |
   ...|................|....................................V...
      | LMAP interface |                                    ^
      +----------------+                                    |
               ^     |                                      |
   Instruction |     |  Report                              |
               |     +-----------------+                    |
               |                       |                    |
               |                       v                   LMAP
          +------------+             +------------+        Scope
          | Controller |             |  Collector |         |
          +------------+             +------------+         V

   Figure A1: Schematic of LMAP-based measurement system,
   with Web server as Measurement Peer

   Another case that is slightly different than this would be the one of
   a ping responder.  This is also an MP, with a helper function, the
   ping server, which is specially deployed to assist the MAs that
   perform pings.  It only has the data plane interface.  This example
   is described in Section 2.

   A third related example would be the case of a traceroute like
   measurement.  In this case, for each packet sent, the router where
   the TTL expires is performing the MP function.  So for a given
   Measurement Task, there is one MA involved and several MPs, one per
   hop.

   In figure A2 we depict the case of an OWAMP responder acting as an
   MP.  In this case, the helper function in addition reports results
   back to the MA.  So it has both a data plane and control interface
   with the MA.

Eardley, et al.          Expires October 2, 2014               [Page 43]
Internet-Draft               LMAP Framework                   March 2014

      +----------------+    OWAMP     +----------------+    ^
      | OWAMP          |<--control--->| MP:            |    |
      | control-client |>test-traffic>| OWAMP server & |   IPPM
      | fetch-client & |<----fetch----| session-rec'ver|  Scope
      | session-sender |              |                |    |
      |                |              +----------------+    |
   ...|................|....................................v...
      | LMAP interface |                                    ^
      +----------------+                                    |
               ^     |                                      |
   Instruction |     |  Report                              |
               |     +-----------------+                    |
               |                       |                    |
               |                       v                  LMAP
          +------------+             +------------+       Scope
          | Controller |             |  Collector |         |
          +------------+             +------------+         v
                                                          IPPM

   Figure A2: Schematic of LMAP-based measurement system,
   with OWAMP server as Measurement Peer

   However, it is also possible to use two Measurement Agents when
   performing one way Measurement Tasks, as described in figure A3
   below.  In this case, MA1 generates the traffic and MA2 receives the
   traffic and send the reports to the Collector.  Note that both MAs
   are instructed by the Controller.  MA1 receives an Instruction to
   send the traffic and MA2 receives an Instruction to measured the
   received traffic and send Reports to the Collector.

Eardley, et al.          Expires October 2, 2014               [Page 44]
Internet-Draft               LMAP Framework                   March 2014

      +----------------+              +----------------+    ^
      |  MA1           |              |  MA2           |  IPPM
      | iperf -u sender|-UDP traffic->| iperf -u recvr |  Scope
      |                |              |                |    v
   ...|................|..............|................|....v...
      | LMAP interface |              | LMAP interface |    ^
      +----------------+              +----------------+    |
               ^                        ^   |               |
   Instruction |    Instruction{Report} |   | Report        |
   {task,      |    +-------------------+   |               |
    schedule}  |    |                       |               |
               |    |                       v              LMAP
          +------------+             +------------+       Scope
          | Controller |             |  Collector |         |
          +------------+             +------------+         v
                                                          IPPM

   Figure A3: Schematic of LMAP-based measurement system,
   with two Measurement Agents cooperating to measure UDP traffic

   Next, we consider Passive Measurement Tasks.  Traffic generated in
   one point in the network flowing towards a given destination and the
   traffic is passively observed in some point along the path.  One way
   to implement this is that the endpoints generating and receiving the
   traffic are not instructed by the Controller; hence they are MPs.
   The MA is located along the path with a passive monitor function that
   measures the traffic.  The MA is instructed by the Controller to
   monitor that particular traffic and to send the Report to the
   Collector.  It is depicted in figure A4 below.

Eardley, et al.          Expires October 2, 2014               [Page 45]
Internet-Draft               LMAP Framework                   March 2014

   +-----+   +----------------+              +------+   ^
   | MP  |   | Passive Monitor|              | MP   | IPPM
   |     |<--|----------------|---traffic--->|      | Scope
   +-----+   |                |              +------+   |
      .......|................|.........................v...........
             | LMAP interface |                                ^
             +----------------+                                |
                        ^     |                                |
            Instruction |     |  Report                        |
                        |     +-----------------+              |
                        |                       |              |
                        |                       v             LMAP
                  +------------+             +------------+   Scope
                  | Controller |             |  Collector |    |
                  +------------+             +------------+    v

   Figure A4: Schematic of LMAP-based measurement system,
   with a Measurement Agent passively monitoring traffic

   Finally, we should consider the case of a router or a switch along
   the measurement path.  This certainly performs an important role in
   the measurement - if packets are not forwarded, the measurement task
   will not work.  Whilst it doesn't has an interface with the
   Controller or Collector, and so fits into the definition of MP,
   usually it is not particularly useful to highlight it as a MP.

11.  Acknowledgments

   This document is a merger of three individual drafts: draft-eardley-
   lmap-terminology-02, draft-akhter-lmap-framework-00, and draft-
   eardley-lmap-framework-02.

   Thanks to Juergen Schoenwaelder for his detailed review of the
   terminology.  Thanks to Charles Cook for a very detailed review of
   -02.

   Thanks to numerous people for much discussion, directly and on the
   LMAP list (apologies to those unintentionally omitted): Alan Clark,
   Alissa Cooper, Andrea Soppera, Barbara Stark, Benoit Claise, Brian
   Trammell, Charles Cook, Dave Thorne, Frode Soerensen, Greg Mirsky,
   Guangqing Deng, Jason Weil, Jean-Francois Tremblay, Jerome Benoit,
   Joachim Fabini, Juergen Schoenwaelder, Jukka Manner, Ken Ko, Michael
   Bugenhagen, Rolf Winter, Sam Crawford, Sharam Hakimi, Steve Miller,
   Ted Lemon, Timothy Carey, Vaibhav Bajpai, William Lupton.

   Philip Eardley, Trevor Burbridge and Marcelo Bagnulo work in part on
   the Leone research project, which receives funding from the European

Eardley, et al.          Expires October 2, 2014               [Page 46]
Internet-Draft               LMAP Framework                   March 2014

   Union Seventh Framework Programme [FP7/2007-2013] under grant
   agreement number 317647.

12.  History

   First WG version, copy of draft-folks-lmap-framework-00.

12.1.  From -00 to -01

   o  new sub-section of possible use of Group-IDs for privacy

   o  tweak to definition of Control protocol

   o  fix typo in figure in S5.4

12.2.  From -01 to -02

   o  change to INFORMATIONAL track (previous version had typo'd
      Standards track)

   o  new definitions for Capabilities Information and Failure
      Information

   o  clarify that diagrams show LMAP-level information flows.
      Underlying protocol could do other interactions, eg to get through
      NAT or for Collector to pull a Report

   o  add hint that after a re-boot should pause random time before re-
      register (to avoid mass calling event)

   o  delete the open issue "what happens if a Controller fails" (normal
      methods can handle)

   o  add some extra words about multiple Tasks in one Schedule

   o  clarify that new Schedule replaces (rather than adds to) and old
      one.  Similarly for new configuration of Measurement Tasks or
      Report Channels.

   o  clarify suppression is temporary stop; send a new Schedule to
      permanently stop Tasks

   o  alter suppression so it is ACKed

   o  add un-suppress message

Eardley, et al.          Expires October 2, 2014               [Page 47]
Internet-Draft               LMAP Framework                   March 2014

   o  expand the text on error reporting, to mention Reporting failures
      (as well as failures to action or execute Measurement Task &
      Schedule)

   o  add some text about how to have Tasks running indefinitely

   o  add that optionally a Report is not sent when there are no
      Measurement Results

   o  add that a Measurement Task may create more than one Measurement
      Result

   o  clarify /amend /expand that Reports include the "raw" Measurement
      Results - any pre-processing is left for lmap2.0

   o  add some cautionary words about what if the Collector unexpectedly
      doesn't hear from a MA

   o  add some extra words about the potential impact of Measurement
      Tasks

   o  clarified various aspects of the privacy section

   o  updated references

   o  minor tweaks

12.3.  From -02 to -03

   o  alignment with the Information Model
      [I-D.burbridge-lmap-information-model] as this is agreed as a WG
      document

   o  One-off and periodic Measurement Schedules are kept separate, so
      that they can be updated independently

   o  Measurement Suppression in a separate sub-section.  Can now
      optionally include particular Measurement Tasks &/or Schedules to
      suppress, and start/stop time

   o  for clarity, concept of Channel split into Control, Report and MA-
      to-Controller Channels

   o  numerous editorial changes, mainly arising from a very detailed
      review by Charles Cook

   o

Eardley, et al.          Expires October 2, 2014               [Page 48]
Internet-Draft               LMAP Framework                   March 2014

12.4.  From -03 to -04

   o  updates following the WG Last Call, with the proposed consensus on
      the various issues as detailed in http://tools.ietf.org/agenda/89/
      slides/slides-89-lmap-2.pdf.  In particular:

   o  tweaked definitions, especially of Measurement Agent and
      Measurement Peer

   o  Instruction - left to each implementation & deployment of LMAP to
      decide on the granularity at which an Instruction Message works

   o  words added about overlapping Measurement Tasks (measurement
      system can handle any way they choose; Report should mention if
      the Task overlapped with another)

   o  Suppression: no defined impact on Passive Measurement Task; extra
      option to suppress on-going Active Measurement Tasks; suppression
      doesn't go to Measurement Peer, since they don't understand
      Instructions

   o  new concept of Data Transfer Task (and therefore adjustment of the
      Channel concept)

   o  enhancement of Results with Subscriber's service parameters -
      could be useful, don't define how but can be included in Report to
      various other sections

   o  various other smaller improvements, arising from the WGLC

   o  Appendix added with examples of Measurement Agents and Peers in
      various deployment scenarios.  To help clarify what these terms
      mean.

   o

13.  Informative References

   [Bur10]    Burkhart, M., Schatzmann, D., Trammell, B., and E. Boschi,
              "The Role of Network Trace anonymisation Under Attack",
              January 2010.

   [Q1741]    Q.1741.7, , "IMT-2000 references to Release 9 of GSM-
              evolved UMTS core network",
              http://www.itu.int/rec/T-REC-Q.1741.7/en, November 2011.

Eardley, et al.          Expires October 2, 2014               [Page 49]
Internet-Draft               LMAP Framework                   March 2014

   [TR-069]   TR-069, , "CPE WAN Management Protocol",
              http://www.broadband-forum.org/technical/trlist.php,
              November 2013.

   [UPnP]     ISO/IEC 29341-x, , "UPnP Device Architecture and UPnP
              Device Control Protocols specifications",
              http://upnp.org/sdcps-and-certification/standards/, 2011.

   [RFC1035]  Mockapetris, P., "Domain names - implementation and
              specification", STD 13, RFC 1035, November 1987.

   [RFC4101]  Rescorla, E. and IAB, "Writing Protocol Models", RFC 4101,
              June 2005.

   [RFC4122]  Leach, P., Mealling, M., and R. Salz, "A Universally
              Unique IDentifier (UUID) URN Namespace", RFC 4122, July
              2005.

   [RFC5357]  Hedayat, K., Krzanowski, R., Morton, A., Yum, K., and J.
              Babiarz, "A Two-Way Active Measurement Protocol (TWAMP)",
              RFC 5357, October 2008.

   [I-D.ietf-lmap-use-cases]
              Linsner, M., Eardley, P., Burbridge, T., and F. Sorensen,
              "Large-Scale Broadband Measurement Use Cases", draft-ietf-
              lmap-use-cases-02 (work in progress), January 2014.

   [I-D.manyfolks-ippm-metric-registry]
              Bagnulo, M., Claise, B., Eardley, P., and A. Morton,
              "Registry for Performance Metrics", draft-manyfolks-ippm-
              metric-registry-00 (work in progress), February 2014.

   [I-D.ietf-homenet-arch]
              Chown, T., Arkko, J., Brandt, A., Troan, O., and J. Weil,
              "IPv6 Home Networking Architecture Principles", draft-
              ietf-homenet-arch-13 (work in progress), March 2014.

   [RFC6419]  Wasserman, M. and P. Seite, "Current Practices for
              Multiple-Interface Hosts", RFC 6419, November 2011.

   [RFC6887]  Wing, D., Cheshire, S., Boucadair, M., Penno, R., and P.
              Selkirk, "Port Control Protocol (PCP)", RFC 6887, April
              2013.

Eardley, et al.          Expires October 2, 2014               [Page 50]
Internet-Draft               LMAP Framework                   March 2014

   [I-D.burbridge-lmap-information-model]
              Burbridge, T., Eardley, P., Bagnulo, M., and J.
              Schoenwaelder, "Information Model for Large-Scale
              Measurement Platforms (LMAP)", draft-burbridge-lmap-
              information-model-01 (work in progress), October 2013.

   [RFC6235]  Boschi, E. and B. Trammell, "IP Flow Anonymization
              Support", RFC 6235, May 2011.

   [RFC6973]  Cooper, A., Tschofenig, H., Aboba, B., Peterson, J.,
              Morris, J., Hansen, M., and R. Smith, "Privacy
              Considerations for Internet Protocols", RFC 6973, July
              2013.

   [I-D.ietf-ippm-lmap-path]
              Bagnulo, M., Burbridge, T., Crawford, S., Eardley, P., and
              A. Morton, "A Reference Path and Measurement Points for
              LMAP", draft-ietf-ippm-lmap-path-02 (work in progress),
              February 2014.

   [RFC4656]  Shalunov, S., Teitelbaum, B., Karp, A., Boote, J., and M.
              Zekauskas, "A One-way Active Measurement Protocol
              (OWAMP)", RFC 4656, September 2006.

   [RFC5357]  Hedayat, K., Krzanowski, R., Morton, A., Yum, K., and J.
              Babiarz, "A Two-Way Active Measurement Protocol (TWAMP)",
              RFC 5357, October 2008.

   [RFC3444]  Pras, A. and J. Schoenwaelder, "On the Difference between
              Information Models and Data Models", RFC 3444, January
              2003.

Authors' Addresses

   Philip Eardley
   BT
   Adastral Park, Martlesham Heath
   Ipswich
   ENGLAND

   Email: philip.eardley@bt.com

Eardley, et al.          Expires October 2, 2014               [Page 51]
Internet-Draft               LMAP Framework                   March 2014

   Al Morton
   AT&T Labs
   200 Laurel Avenue South
   Middletown, NJ
   USA

   Email: acmorton@att.com

   Marcelo Bagnulo
   Universidad Carlos III de Madrid
   Av. Universidad 30
   Leganes, Madrid  28911
   SPAIN

   Phone: 34 91 6249500
   Email: marcelo@it.uc3m.es
   URI:   http://www.it.uc3m.es

   Trevor Burbridge
   BT
   Adastral Park, Martlesham Heath
   Ipswich
   ENGLAND

   Email: trevor.burbridge@bt.com

   Paul Aitken
   Cisco Systems, Inc.
   96 Commercial Street
   Edinburgh, Scotland  EH6 6LX
   UK

   Email: paitken@cisco.com

   Aamer Akhter
   Cisco Systems, Inc.
   7025 Kit Creek Road
   RTP, NC  27709
   USA

   Email: aakhter@cisco.com

Eardley, et al.          Expires October 2, 2014               [Page 52]