Behave S. Sivakumar
Internet-Draft R. Penno
Intended status: Standards Track Cisco Systems
Expires: June 3, 2014 November 30, 2013
IPFIX Information Elements for logging NAT Events
draft-ietf-behave-ipfix-nat-logging-02
Abstract
NAT devices are required to log events like creation and deletion of
translations and information about the resources it is managing. The
logs are required in many cases to identify an attacker or a host
that was used to launch malicious attacks and/or for various other
purposes of accounting. Since there is no standard way of logging
this information, different NAT devices behave differently and hence
it is difficult to expect a consistent behavior. The lack of a
consistent way makes it difficult to write the collector applications
that would receive this data and process it to present useful
information. This document describes the information that is
required to be logged by the NAT devices.
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 June 3, 2014.
Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the
document authors. All rights reserved.
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
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publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
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Table of Contents
1. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
3. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 4
5. Event based logging . . . . . . . . . . . . . . . . . . . . . 4
5.1. Logging of destination information . . . . . . . . . . . 5
5.2. Information Elements . . . . . . . . . . . . . . . . . . 5
5.3. Definition of NAT Events . . . . . . . . . . . . . . . . 7
5.4. Quota exceeded - natLimitEvent types . . . . . . . . . . 8
5.5. Templates for NAT Events . . . . . . . . . . . . . . . . 8
5.5.1. NAT44 create and delete session events . . . . . . . 8
5.5.2. NAT64 create and delete session events . . . . . . . 9
5.5.3. NAT44 BIB create and delete events . . . . . . . . . 9
5.5.4. NAT64 BIB create and delete events . . . . . . . . . 10
5.5.5. Addresses Exhausted event . . . . . . . . . . . . . . 10
5.5.6. Ports Exhausted event . . . . . . . . . . . . . . . . 11
5.5.7. Quota exceeded . . . . . . . . . . . . . . . . . . . 11
5.5.8. Address binding create and delete events . . . . . . 11
5.5.9. Port block allocation and de-allocation . . . . . . . 12
6. Encoding . . . . . . . . . . . . . . . . . . . . . . . . . . 13
6.1. IPFIX . . . . . . . . . . . . . . . . . . . . . . . . . . 13
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 13
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
9. Management Considerations . . . . . . . . . . . . . . . . . . 13
9.1. Ability to collect events from multiple NAT devices . . . 13
9.2. Ability to suppress events . . . . . . . . . . . . . . . 14
10. Security Considerations . . . . . . . . . . . . . . . . . . . 14
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 14
11.1. Normative References . . . . . . . . . . . . . . . . . . 14
11.2. Informative References . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15
1. Terminology
The usage of the term "NAT device" in this document refer to any
NAT44 and NAT64 devices. The usage of the term "collector" refers to
any device that receives the binary data from a NAT device and
converts that into meaningful information. This document uses the
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term "Session" as it is defined in [RFC2663] and the term BIB as it
is defined in [RFC6146]. The usage of the term Information Element
(IE) is defined in [RFC5101bis].
2. Introduction
The IPFIX Protocol [RFC5101bis] defines a generic push mechanism for
exporting information and events. The IPFIX Information Model
[IPFIX-IANA] defines a set of standard Information Elements (IEs)
which can be carried by the IPFIX protocol. This document details
the IPFIX Information Elements(IEs) that are required for logging by
a NAT device. The document will specify the format of the IE's that
are required to be logged by the NAT device and all the optional
fields. The fields specified in this document are gleaned from
[RFC4787] and [RFC5382].
Test [3GPP]
This document and [I-D.behave-syslog-nat-logging] are provided in
order to standardize the events and parameters to be recorded, using
IPFIX [RFC5101bis] and SYSLOG [RFC5424]respectively.
2.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
3. Scope
This document provides the information model to be used for logging
the NAT devices including Carrier Grade NAT (CGN) events. This
document focuses exclusively on the specification of IPFIX IE's.
This document does not provide guidance on the transport protocol
like TCP, UDP or SCTP that is to be used to log NAT events. The log
events SHOULD NOT be lost but the choice of the actual transport
protocol is beyond the scope of this document.
The existing IANA IPFIX IEs registry [IPFIX-IANA] already has
assignments for many NAT logging events. For convenience, this
document uses those same IEs. However, as stated earlier, this
document is not defining IPFIX or NetFlow v9 as the framework for
logging. Rather, the information contained in these elements is
within the scope of this document.
This document assumes that the NAT device will use the existing IPFIX
framework to send the log events to the collector. This would mean
that the NAT device will specify the template that it is going to use
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for each of the events. The templates can be of varying length and
there could be multiple templates that a NAT device could use to log
the events.
The implementation details of the collector application is beyond the
scope of this document.
The optimization of logging the NAT events are left to the
implementation and are beyond the scope of this document.
4. Applicability
NAT logging based on IPFIX uses binary encoding and hence is very
efficient. IPFIX based logging is recommended for environments where
a high volume of logging is required, for example, where per-flow
logging is needed. However, IPFIX based logging requires a collector
that processes the binary data and requires a network management
application that converts this binary data to a human readable
format.
5. Event based logging
An event in a NAT device can be viewed as a happening as it relates
to the management of NAT resources. The creation and deletion of NAT
sessions and bindings are examples of events as it results in the
resources (addresses and ports) being allocated or freed. The events
can happen either through the processing of data packets flowing
through the NAT device or through an external entity installing
policies on the NAT router or as a result of an asynchronous event
like a timer. The list of events are provided in Section 4.1. Each
of these events SHOULD be logged, unless they are administratively
prohibited. A NAT device MAY log these events to multiple collectors
if redundancy is required. The network administrator will specify
the collectors to which the log records are to be sent.
A collector may receive NAT events from multiple CGN devices and
should be able to distinguish between the devices. Each CGN device
should have a unique source ID to identify themselves. The source ID
is part of the IPFIX template and data exchange.
Prior to logging any events, the NAT device MUST send the template of
the record to the collector to advertise the format of the data
record that it is using to send the events. The templates can be
exchanged as frequently as required given the reliability of the
connection. There SHOULD be a configurable timer for controlling the
template refresh. NAT device SHOULD combine as many events as
possible in a single packet to effectively utilize the network
bandwidth.
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5.1. Logging of destination information
Logging of destination information in a NAT event has been discussed
in [RFC6302] and [RFC6888]. Logging of destination information
increases the size of each record and increases the need for storage
considerably. It increases the number of log events generated
because when the same user connects to a different destination, it
results in a log record per destination address. Logging of
destination information also results in the loss of privacy and hence
should be done with caution. However, this draft provides the
necessary fields to log the destination information in cases where
they are required to be logged.
5.2. Information Elements
The templates could contain a subset of the Information Elements(IEs)
shown in Table 1 depending upon the event being logged. For example
a NAT44 session creation template record will contain,
{sourceIPv4Adress, postNATSourceIPv4Address, destinationIpv4Address,
postNATDestinationIPv4Address, sourceTransportPort,
postNAPTSourceTransportPort, destinationTransportPort,
postNAPTDestTransportPort, natOriginatingAddressRealm, natEvent,
timeStamp}
An example of the actual event data record is shown below - in a
readable form
{192.168.16.1, 201.1.1.100, 207.85.231.104, 207.85.231.104, 14800,
1024, 80, 80, 0, 1, 09:20:10:789}
A single NAT device could be exporting multiple templates and the
collector should support receiving multiple templates from the same
source.
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The following is the table of all the IE's that a CGN device would
need to export the events. The formats of the IE's and the IPFIX IDs
are listed below.
+----------------------------------+--------+---------+-------------+
| Field Name | Size | IANA | Description |
| | (bits) | IPFIX | |
| | | ID | |
+----------------------------------+--------+---------+-------------+
| timeStamp | 64 | 323 | System Time |
| | | | when the |
| | | | event |
| | | | occured. |
| vlanID | 16 | 58 | VLAN ID in |
| | | | case of |
| | | | overlapping |
| | | | networks |
| ingressVRFID | 32 | 234 | VRF ID in |
| | | | case of |
| | | | overlapping |
| | | | networks |
| sourceIPv4Address | 32 | 8 | Source IPv4 |
| | | | Address |
| postNATSourceIPv4Address | 32 | 225 | Translated |
| | | | Source IPv4 |
| | | | Address |
| protocolIdentifier | 8 | 4 | Transport |
| | | | protocol |
| sourceTransportPort | 16 | 7 | Source Port |
| postNAPTsourceTransportPort | 16 | 227 | Translated |
| | | | Source port |
| destinationIPv4Address | 32 | 12 | Destination |
| | | | IPv4 |
| | | | Address |
| postNATDestinationIPv4Address | 32 | 226 | Translated |
| | | | IPv4 |
| | | | destination |
| | | | address |
| destinationTransportPort | 16 | 11 | Destination |
| | | | port |
| postNAPTdestinationTransportPort | 16 | 228 | Translated |
| | | | Destination |
| | | | port |
| sourceIPv6Address | 27 | 128 | Source IPv6 |
| | | | address |
| destinationIPv6Address | 128 | 28 | Destination |
| | | | IPv6 |
| | | | address |
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| postNATSourceIPv6Address | 128 | 281 | Translated |
| | | | source IPv6 |
| | | | addresss |
| postNATDestinationIPv6Address | 128 | 282 | Translated |
| | | | Destination |
| | | | IPv6 |
| | | | address |
| natOriginatingAddressRealm | 8 | 229 | Address |
| | | | Realm |
| natEvent | 8 | 230 | Type of |
| | | | Event |
| portRangeStart | 16 | 361 | Allocated |
| | | | port block |
| | | | start |
| portRangeEnd | 16 | 362 | Allocated |
| | | | Port block |
| | | | end |
| portRangeStepSize | 16 | 363 | Step size |
| | | | of next |
| | | | port |
| portRangeNumPorts | 16 | 364 | Number of |
| | | | ports |
+----------------------------------+--------+---------+-------------+
Table 1: Template format Table
5.3. Definition of NAT Events
The following are the list of NAT events and the proposed event
values. The list can be expanded in the future as necessary. The
data record will have the corresponding natEvent value to identify
the event that is being logged.
+--------------------------+--------+
| Event Name | Values |
+--------------------------+--------+
| NAT44 Session create | 1 |
| NAT44 Session delete | 2 |
| NAT Addresses exhausted | 3 |
| NAT64 Session create | 4 |
| NAT64 Session delete | 5 |
| NAT44 BIB create | 6 |
| NAT44 BIB delete | 7 |
| NAT64 BIB create | 8 |
| NAT64 BIB delete | 9 |
| NAT ports exhausted | 10 |
| Quota exceeded | 11 |
| Address binding create | 12 |
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| Address binding delete | 13 |
| Port block allocation | 14 |
| Port block de-allocation | 15 |
+--------------------------+--------+
Table 2: NAT Event ID table
5.4. Quota exceeded - natLimitEvent types
The following table shows the sub event types for the Quota exceeded
event
+---------------------------+--------+
| Quota Exceeded Event Name | Values |
+---------------------------+--------+
| Max Session entries | 1 |
| Max BIB entries | 2 |
| Max entries per user | 3 |
+---------------------------+--------+
Table 3: Sub Event ID table
5.5. Templates for NAT Events
The following is the template of events that will have to logged.
The events below are identified at the time of this writing but the
events are expandable. Depending on the implementation and
configuration various IE's specified can be included or ignored.
5.5.1. NAT44 create and delete session events
These events will be generated when a NAT44 session is created or
deleted. The template will be the same, the natEvent will indicate
whether it is a create or a delete event. The following is a
template of the event.
+----------------------------------+-------------+-----------+
| Field Name | Size (bits) | Mandatory |
+----------------------------------+-------------+-----------+
| timeStamp | 64 | Yes |
| vlanID/ingressVRFID | 32 | No |
| sourceIPv4Address | 32 | Yes |
| postNATSourceIPv4Address | 32 | Yes |
| protocolIdentifier | 8 | Yes |
| sourceTransportPort | 16 | Yes |
| postNAPTsourceTransportPort | 16 | Yes |
| destinationIPv4Address | 32 | No |
| postNATDestinationIPv4Address | 32 | No |
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| destinationTransportPort | 16 | No |
| postNAPTdestinationTransportPort | 16 | No |
| natOriginatingAddressRealm | 8 | No |
| natEvent | 8 | Yes |
+----------------------------------+-------------+-----------+
Table 4: NAT44 Session delete/create template
5.5.2. NAT64 create and delete session events
These events will be generated when a NAT64 session is created or
deleted. The following is a template of the event.
+----------------------------------+-------------+-----------+
| Field Name | Size (bits) | Mandatory |
+----------------------------------+-------------+-----------+
| timeStamp | 64 | Yes |
| vlanID/ingressVRFID | 32 | No |
| sourceIPv6Address | 128 | Yes |
| postNATSourceIPv4Address | 32 | Yes |
| protocolIdentifier | 8 | Yes |
| sourceTransportPort | 16 | Yes |
| postNAPTsourceTransportPort | 16 | Yes |
| destinationIPv6Address | 128 | No |
| postNATDestinationIPv4Address | 32 | No |
| destinationTransportPort | 16 | No |
| postNAPTdestinationTransportPort | 16 | No |
| natOriginatingAddressRealm | 8 | No |
| natEvent | 8 | Yes |
+----------------------------------+-------------+-----------+
Table 5: NAT64 session create/delete event template
5.5.3. NAT44 BIB create and delete events
These events will be generated when a NAT44 Bind entry is created or
deleted. The following is a template of the event.
+-----------------------------+-------------+-----------+
| Field Name | Size (bits) | Mandatory |
+-----------------------------+-------------+-----------+
| timeStamp | 64 | Yes |
| vlanID/ingressVRFID | 32 | No |
| sourceIPv4Address | 32 | Yes |
| postNATSourceIPv4Address | 32 | Yes |
| protocolIdentifier | 8 | No |
| sourceTransportPort | 16 | No |
| postNAPTsourceTransportPort | 16 | No |
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| natOriginatingAddressRealm | 8 | No |
| natEvent | 8 | Yes |
+-----------------------------+-------------+-----------+
Table 6: NAT44 BIB create/delete event template
5.5.4. NAT64 BIB create and delete events
These events will be generated when a NAT64 Bind entry is created or
deleted. The following is a template of the event.
+-----------------------------+-------------+-----------+
| Field Name | Size (bits) | Mandatory |
+-----------------------------+-------------+-----------+
| timeStamp | 64 | Yes |
| vlanID/ingressVRFID | 32 | No |
| sourceIPv6Address | 128 | Yes |
| postNATSourceIPv4Address | 32 | Yes |
| protocolIdentifier | 8 | No |
| sourceTransportPort | 16 | No |
| postNAPTsourceTransportPort | 16 | No |
| natOriginatingAddressRealm | 8 | No |
| natEvent | 8 | Yes |
+-----------------------------+-------------+-----------+
Table 7: NAT64 BIB create/delete event template
5.5.5. Addresses Exhausted event
This event will be generated when a NAT device runs out of global
IPv4 addresses in a given pool of addresses. Typically, this event
would mean that the NAT device wont be able to create any new
translations until some addresses/ports are freed. This event SHOULD
be rate limited as many packets hitting the device at the same time
will trigger a burst of addresses exhausted events.
The following is a template of the event.
+-------------+-------------+-----------+
| Field Name | Size (bits) | Mandatory |
+-------------+-------------+-----------+
| timeStamp | 64 | Yes |
| natEvent | 8 | Yes |
| natPoolName | String | Yes |
+-------------+-------------+-----------+
Table 8: NAT Address Exhausted event template
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5.5.6. Ports Exhausted event
This event will be generated when a NAT device runs out of ports for
a global IPv4 address. Port exhaustion shall be reported per
protocol (UDP, TCP etc). This event SHOULD be rate limited as many
packets hitting the device at the same time will trigger a burst of
port exhausted events.
The following is a template of the event.
+--------------------------+-------------+-----------+
| Field Name | Size (bits) | Mandatory |
+--------------------------+-------------+-----------+
| timeStamp | 64 | Yes |
| natEvent | 8 | Yes |
| postNATSourceIPv4Address | 32 | Yes |
| protocolIdentifier | 8 | Yes |
+--------------------------+-------------+-----------+
Table 9: NAT Ports Exhausted event template
5.5.7. Quota exceeded
This event will be generated when a NAT device cannot allocate
resources as a result of an administratively defined policy. The
examples of Quota exceeded are to allow only certain number of NAT
sessions per device, certain number of NAT sessions per user etc.
The following is a template of the event.
+--------------------+-------------+---------------+
| Field Name | Size (bits) | Mandatory |
+--------------------+-------------+---------------+
| timeStamp | 64 | Yes |
| natEvent | 8 | Yes |
| natLimitEvent | 32 | Yes |
| sourceIPv4 address | 32 | Yes for NAT44 |
| sourceIPv6 address | 128 | Yes for NAT64 |
+--------------------+-------------+---------------+
Table 10: NAT Quota Exceeded event template
5.5.8. Address binding create and delete events
These events will be generated when a NAT device binds a local
address with a global address and when the global address is freed.
This binding event happens when the first packet of the first flow
from a host in the private realm.
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+--------------------------------+-------------+---------------+
| Field Name | Size (bits) | Mandatory |
+--------------------------------+-------------+---------------+
| timeStamp | 64 | Yes |
| natEvent | 8 | Yes |
| sourceIPv4 address | 32 | Yes for NAT44 |
| sourceIPv6 address | 128 | Yes for NAT64 |
| Translated Source IPv4 Address | 32 | Yes |
+--------------------------------+-------------+---------------+
Table 11: NAT Address Binding template
5.5.9. Port block allocation and de-allocation
This event will be generated when a NAT device allocates/de-allocates
ports in a bulk fashion, as opposed to allocating a port on a per
flow basis.
portRangeStart represents the starting value of the range.
portRangeEnd represents the ending value of the range.
portRangeNumPorts represents the number of ports that are allocated
to the user.
portRangeStepSize represents the step size in case of non-contiguous
port allocation.
NAT devices would do this in order to reduce logs and potentially to
limit the number of connections a subscriber is allowed to use. In
the following Port Block allocation template, the portRangeStart must
be specified. Along with portRangeStart, atleast one of
portRangeEnd, portRangeStepSize or portRangeNumPorts MUST be
specified. If portRangeEnd is specified, it MUST NOT be lesser than
portRangeStart. The value of portRangeStepSize MUST be between 1 and
32K.
It is up to the implementation to choose to consolidate log records
in case two consecutive port ranges for the same user are allocated
or freed.
+--------------------------------+-------------+---------------+
| Field Name | Size (bits) | Mandatory |
+--------------------------------+-------------+---------------+
| timeStamp | 64 | Yes |
| sourceIPv4 address | 32 | Yes for NAT44 |
| sourceIPv6 address | 128 | Yes for NAT64 |
| Translated Source IPv4 Address | 32 | Yes |
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| portRangeStart | 16 | Yes |
| portRangeEnd | 16 | No |
| portRangeStepSize | 16 | No |
| portRangeNumPorts | 16 | No |
+--------------------------------+-------------+---------------+
Table 12: NAT Port Block Allocation event template
6. Encoding
6.1. IPFIX
This document uses IPFIX as the encoding mechanism to describe the
logging of NAT events. However, the information that should be
logged SHOULD be the same irrespective of what kind of encoding
scheme is used. IPFIX is chosen because is it an IETF standard that
meets all the needs for a reliable logging mechanism. IPFIX provides
the flexibility to the logging device to define the data sets that it
is logging. The IEs specified for logging MUST be the same
irrespective of the encoding mechanism used.
7. Acknowledgements
Thanks to Dan Wing, Selvi Shanmugam, Mohamed Boucadir, Jacni Qin
Ramji Vaithianathan, Simon Perreault, Jean-Francois Tremblay, Paul
Aitken and Julia Renouard for their review and comments.
8. IANA Considerations
There are no IANA considerations for this document.
9. Management Considerations
This section considers requirements for management of the log system
to support logging of the events described above. It first covers
requirements applicable to log management in general. Any additional
standardization required to fullfil these requirements is out of
scope of the present document. Some management considerations is
covered in [I-D.behave-syslog-nat-logging]. This document covers the
additional considerations.
9.1. Ability to collect events from multiple NAT devices
An IPFIX collector should be able to collect events from multiple NAT
devices and be able to decipher events based on the sourceID in the
IPFIX header.
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9.2. Ability to suppress events
The exhaustion events can be overwhelming during traffic bursts and
hence should be handled by the NAT devices to rate limit them before
sending them to the collectors. For eg. when the port exhaustion
happens during bursty conditions, instead of sending a port
exhaustion event for every packet, the exhaustion events should be
rate limited by the NAT device.
10. Security Considerations
None.
11. References
11.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2663] Srisuresh, P. and M. Holdrege, "IP Network Address
Translator (NAT) Terminology and Considerations", RFC
2663, August 1999.
[RFC4787] Audet, F. and C. Jennings, "Network Address Translation
(NAT) Behavioral Requirements for Unicast UDP", BCP 127,
RFC 4787, January 2007.
[RFC5382] Guha, S., Biswas, K., Ford, B., Sivakumar, S., and P.
Srisuresh, "NAT Behavioral Requirements for TCP", BCP 142,
RFC 5382, October 2008.
[RFC6146] Bagnulo, M., Matthews, P., and I. van Beijnum, "Stateful
NAT64: Network Address and Protocol Translation from IPv6
Clients to IPv4 Servers", RFC 6146, April 2011.
[RFC6302] Durand, A., Gashinsky, I., Lee, D., and S. Sheppard,
"Logging Recommendations for Internet-Facing Servers", BCP
162, RFC 6302, June 2011.
[RFC6888] Perreault, S., Yamagata, I., Miyakawa, S., Nakagawa, A.,
and H. Ashida, "Common Requirements for Carrier-Grade NATs
(CGNs)", BCP 127, RFC 6888, April 2013.
11.2. Informative References
[I-D.ietf-behave-syslog-nat-logging]
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Chen, Z., Zhou, C., Tsou, T., and T. Taylor, "Syslog
Format for NAT Logging", draft-ietf-behave-syslog-nat-
logging-05 (work in progress), October 2013.
[IPFIX-IANA]
IANA, "IPFIX Information Elements registry",
<http://www.iana.org/assignments/ipfix>.
[RFC5101bis]
Claise, B. and B. Trammel, "Specification of the IP Flow
Information eXport (IPFIX) Protocol for the Exchange of
Flow Information", July 2013.
[RFC5102bis]
Claise, B. and B. Trammel, "Information Model for IP Flow
Information eXport (IPFIX)", February 2013.
[RFC5470] Sadasivan, G., Brownlee, N., Claise, B., and J. Quittek,
"Architecture for IP Flow Information Export", RFC 5470,
March 2009.
Authors' Addresses
Senthil Sivakumar
Cisco Systems
7100-8 Kit Creek Road
Research Triangle Park, North Carolina 27709
USA
Phone: +1 919 392 5158
Email: ssenthil@cisco.com
Renaldo Penno
Cisco Systems
170 W Tasman Drive
San Jose, California 95035
USA
Email: repenno@cisco.com
Sivakumar & Penno Expires June 3, 2014 [Page 15]
