Configuration Negotiation Protocol for Network Devices
draft-jiang-config-negotiation-protocol-01
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| Authors | Sheng Jiang , Brian E. Carpenter , Bing Liu , Yuanbin Yin | ||
| Last updated | 2014-04-22 | ||
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draft-jiang-config-negotiation-protocol-01
Network Working Group S. Jiang
Internet-Draft Huawei Technologies Co., Ltd
Intended status: Standards Track B. Carpenter
Expires: October 23, 2014 Univ. of Auckland
B. Liu
Y. Yin
Huawei Technologies Co., Ltd
April 21, 2014
Configuration Negotiation Protocol for Network Devices
draft-jiang-config-negotiation-protocol-01
Abstract
This document defines a new protocol that enables intelligent devices
to dynamically negotiate their configuration with counterpart
devices. This document only defines a general protocol as a
negotiation platform while the negotiation objectives for specific
scenarios are out of scope.
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
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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 23, 2014.
Copyright Notice
Copyright (c) 2014 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
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
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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. Requirements Language and Terminology . . . . . . . . . . . . 3
3. CNP Protocol Overview . . . . . . . . . . . . . . . . . . . . 4
3.1. IP Version Independent . . . . . . . . . . . . . . . . . 4
3.2. Objective Oriented Discovery Mechanism . . . . . . . . . 4
3.3. Neighbor Diverting Discovery Mechanism . . . . . . . . . 5
3.4. Certificate-based Security Mechanism . . . . . . . . . . 6
3.4.1. Support for algorithm agility . . . . . . . . . . . . 6
3.4.2. Message validation on reception . . . . . . . . . . . 7
3.4.3. TimeStamp checking . . . . . . . . . . . . . . . . . 7
3.5. Negotiation Procedures . . . . . . . . . . . . . . . . . 9
4. CNP Constants . . . . . . . . . . . . . . . . . . . . . . . . 9
5. Device Identifier and Certificate Tag . . . . . . . . . . . . 9
6. Session Identifier . . . . . . . . . . . . . . . . . . . . . 10
7. CNP Messages . . . . . . . . . . . . . . . . . . . . . . . . 10
7.1. CNP Messsage Format . . . . . . . . . . . . . . . . . . . 10
7.2. Request Message . . . . . . . . . . . . . . . . . . . . . 11
7.3. Negotiation Message . . . . . . . . . . . . . . . . . . . 11
7.4. Negotiation-ending Message . . . . . . . . . . . . . . . 12
7.5. Confirm-waiting Message . . . . . . . . . . . . . . . . . 12
8. CNP General Options . . . . . . . . . . . . . . . . . . . . . 12
8.1. Format of CNP Options . . . . . . . . . . . . . . . . . . 12
8.2. Divert Option . . . . . . . . . . . . . . . . . . . . . . 13
8.3. Accept Option . . . . . . . . . . . . . . . . . . . . . . 14
8.4. Decline Option . . . . . . . . . . . . . . . . . . . . . 14
8.5. Waiting Time Option . . . . . . . . . . . . . . . . . . . 15
8.6. Certificate Option . . . . . . . . . . . . . . . . . . . 15
8.7. Signature Option . . . . . . . . . . . . . . . . . . . . 16
8.8. Locator Options . . . . . . . . . . . . . . . . . . . . . 17
8.8.1. Locator IPv4 address option . . . . . . . . . . . . . 17
8.8.2. Locator IPv6 address option . . . . . . . . . . . . . 17
8.8.3. Locator FQDN option . . . . . . . . . . . . . . . . . 18
9. Objective Options and Considerations . . . . . . . . . . . . 18
9.1. Organizing of CNP Option . . . . . . . . . . . . . . . . 19
9.2. Vendor Specific Options . . . . . . . . . . . . . . . . . 19
9.3. Experimental Options . . . . . . . . . . . . . . . . . . 19
10. Items for Future Work . . . . . . . . . . . . . . . . . . . . 19
11. Security Considerations . . . . . . . . . . . . . . . . . . . 20
12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20
13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 22
14. Change log [RFC Editor: Please remove] . . . . . . . . . . . 22
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15. References . . . . . . . . . . . . . . . . . . . . . . . . . 22
15.1. Normative References . . . . . . . . . . . . . . . . . . 22
15.2. Informative References . . . . . . . . . . . . . . . . . 22
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 23
1. Introduction
The success of Internet has made the IP-based networks bigger and
more complicated. The large-scaled ISP networks have become more and
more for human based management. Also the operation cost is growing
quickly. Consequently, there are therefore increased requirements
for autonomy in the networks. In order to fulfil autonomy, devices
that are more intelligent need to be able to negotiate directly with
each other. [I-D.jiang-config-negotiation-ps] describes the
requirements and application scenarios for network devices
negotiation. It also describes a behavior model of a generic
negotiation protocol. The design of Configuration Negotiation
Protocol (CNP) in this document is mainly based on this behavior
model.
Although many negotiations may happen between distributed horizontal
peers, the main target scenarios are still hierarchy networks, which
is the major structure of current large-scaled ISP networks. Thus,
where necessary, we assume that each network element has a
hierarchical superior. Of course, the protocol itself is capable of
being used in a small and/or flat network structure, too.
This document defines a generic negotiation protocol, named
Configuration Negotiation Protocol (CNP), that can be used to control
decision process among distributed devices or between networks. The
newly defined CNP in this document adapts a tight certificate-based
mechanism, which needs the network operator runs a Public Key
Infrastracture (PKI, [RFC5280]) system. The document introduce a new
discovery mechanism, which is based on neighbor learning process and
negotiation objective oriented.
2. Requirements Language and Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
[RFC2119] when they appear in ALL CAPS. When these words are not in
ALL CAPS (such as "should" or "Should"), they have their usual
English meanings, and are not to be interpreted as [RFC2119] key
words.
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o Negotiation Objective: specific negotiation content, which needs
to be decided in coordination with another network device. It is
naturally based on a specific service or function or action.
o Negotiation Counterpart: a peer device with which the requesting
device negotiates a specific negotiation objective.
o Device Identifier: a public key, which identifies the device in
CNP messages. It is assumed that its associated private key is
maintained in the device only.
o Device Certificate: A certificate for a single device, also the
identitier of the device, further described in Section 5.
o Device Certificate Tag: a tag, which is bound to the device
identitier. It is used to present Device Certificate in short
form.
3. CNP Protocol Overview
The Configuration Negotiation protocol is designed to be a generic
platform, which is independent from the negotiation contents. It
only takes care of the general intercommunication between negotiation
counterparts. The negotiation contents vary, giving the various
negotiation objectives and the different pairs of negotiating
counterparts.
The CNP has been designed based on simple initiator/responder model,
while multiple-party negotiations could be completed by indirect
steps.
3.1. IP Version Independent
To be a generic platform, CNP should be IP version independent. In
other words, it should be able to run over IPv6 and IPv4. Its
messages and general options are neutral with respect to the IP
version.
However, some functions, such as broadcasting on a link, may have to
be IP version dependent. For these parts, the document defines
support for both IP versions separately.
3.2. Objective Oriented Discovery Mechanism
Typically, one network device has multiple functions. It may be
involved in different negotiation processes according to different
negotiation objectives. Therefore, the traditional topology-oriented
device discovery mechanisms are not sufficient for the CNP. A new
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discovery mechanims is needed to find negotiation counterparts based
on a specific negotiation objective. At a result, an objective-based
discovery mechanism has been designed, in this document.
For every new negotiation objective, the negotiation requesting
device needs to start a new discovery process in order to find the
proper negotiation counterpart. Because a listening CNP-enabled
device has to know the requested negotiation objective to decide
whether it is a proper negotiation counterpart and make a response,
the discovery process needs to be tightly coupled with the request
process. Therefore, in this document, the discovery process is
merged into the request process. There is no need for an independent
discovery message and process.
3.3. Neighbor Diverting Discovery Mechanism
We now discuss the general flow of Request, Negotiation, and
Negotiation-Ending messages, and Accept, Decline and Divert options.
Details are given later.
Every Request message is sent to the ALL_CNP_NEIGHBOR mutlicast
address Section 4.
If the neighbor device is a proper negotiation counterpart, it MAY
respond with a Negotiation message to start a negotiation process, or
with a Negotiation-Ending message in the case of a clear Accept or
Decline.
If the neigbor device is not a proper negotiation counterpart for the
objective given in the Request message, but knows a proper
negotiation counterpart, for example because it negotiated the same
objective with that negotiation counterpart before, it SHOULD respond
with a Negotiation-Ending message with a Divert option pointed to the
proper negotiation counterpart. If the neigbor device is not a
proper negotiation counterpart, but does not know a proper
negotiation counterpart, it SHOULD respond with a Negotiation-Ending
message with a Divert option pointed to its hierachical upstream
device.
After a CNP device successfully negotiated a specific objective with
a negotiation counterpart, it SHOULD record this negotiation
counterpart with this objective type locally. This record may be
used for future negotiation or to pass to its neighbor as a Divert
option. This learning mechanism should be able to support most
network establishment scenarios.
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3.4. Certificate-based Security Mechanism
A certification based security mechanism provides security properties
for CNP:
o the identity of a CNP message sender can be verified by a
recipient.
o the integrity of CNP message can be checked by the recipient of
the message.
o anti-replay protection on the CNP message recipient.
The authority of the CNP message sender depends on a Public Key
Infrastructure system, which should normally be run by the network
operator.
A Request message MUST carry a Certificate option, defined in
Section 8.6. The first Negotiation Message, responsing to a Request
message, SHOULD also carry a Certificate option.
Every messages MUST carry a signature option, defined in Section 8.7.
For now, the authors do not think packet size is problem. In this
CNP specification, there SHOULD NOT be multiple certificates in a
single message. The current most used public keys are 1024/2048
bits, some may reach 4096. With overhead included, a single
certificate is less than 500 bytes. Messages should be far shorter
than the normal packet MTU.
3.4.1. Support for algorithm agility
Hash functions are used to provide message integrity checks. In
order to provide a means of addressing problems that may emerge in
the future with existing hash algorithms, as recommended in
[RFC4270], a mechanism for negotiating the use of more secure hashes
in the future is provided.
In addition to hash algorithm agility, a mechanism for signature
algorithm agility is also provided.
The support for algorithm agility in this document is mainly a
unilateral notification mechanism from sender to recipient. If the
recipient does not support the algorithm used by the sender, it
cannot authenticate the message. Senders in a single administrative
domain are not required to upgrade to a new algorithm simultaneously.
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So far, the algorithm agility is supported by one-way notification,
rather than negotiation mode. As defined in Section 8.7, the sender
notifies the recipient what hash/signature algorithms it used. If
the responder doesn't know a new algorithm used by the sender, the
negotiation request would fail. In order to establish a negotiation
session, the sender may fall back to an older, less preferred
algorithm.
3.4.2. Message validation on reception
When receiving a CNP message, a recipient SHOULD discard the CNP
message if the Signature option is absent, or the Certificate option
is in a Request Message.
For the Request message and the Response message with a Certification
Option, the recipient SHOULD first check the authority of this sender
following the rules defined in [RFC5280]. After successful authority
validation, an implementation MUST add the sender's certification
into the local trust certificate record indexed by the associated
Device Certifice Tag, defined in Section 5.
The recipient MUST now authenticate the sender by verifying the
Signature and checking timestamp, as specified in Section 3.4.3. The
order of two procedures is left as an implementation decision. It is
RECOMMENDED to check timestamp first, because signature verification
is much more computationally expensive.
The signature field verification MUST show that the signature has
been calculated as specified in Section 8.7. The public key used for
signature validation is obtained from the certificate either carried
by the message or found from a local trust certificate record by
searching the message-carried Device Certicate Tag.
Only the messages that get through both the signature verifications
and timestamp check are accepted and continue to be handled for their
contained CNP options. Messages that do not pass the above tests
MUST be discarded or treated as unsecure messages.
3.4.3. TimeStamp checking
Recipients SHOULD be configured with an allowed timestamp Delta
value, a "fuzz factor" for comparisons, and an allowed clock drift
parameter. The recommended default value for the allowed Delta is
300 seconds (5 minutes); for fuzz factor 1 second; and for clock
drift, 0.01 second.
To facilitate timestamp checking, each recipient SHOULD store the
following information for each sender:
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o The receive time of the last received and accepted CNP message.
This is called RDlast.
o The time stamp in the last received and accepted CNP message.
This is called TSlast.
An accepted CNP message is any successfully verified (for both
timestamp check and signature verification) CNP message from the
given peer. It initiates the update of the above variables.
Recipients MUST then check the Timestamp field as follows:
o When a message is received from a new peer (i.e., one that is not
stored in the cache), the received timestamp, TSnew, is checked,
and the message is accepted if the timestamp is recent enough to
the reception time of the packet, RDnew:
-Delta < (RDnew - TSnew) < +Delta
The RDnew and TSnew values SHOULD be stored in the cache as RDlast
and TSlast.
o When a message is received from a known peer (i.e., one that
already has an entry in the cache), the timestamp is checked
against the previously received CNP message:
TSnew + fuzz > TSlast + (RDnew - RDlast) x (1 - drift) - fuzz
If this inequality does not hold, the recipient SHOULD silently
discard the message. If, on the other hand, the inequality holds,
the recipient SHOULD process the message.
Moreover, if the above inequality holds and TSnew > TSlast, the
recipient SHOULD update RDlast and TSlast. Otherwise, the
recipient MUST NOT update RDlast or TSlast.
An implementation MAY use some mechanism such as a timestamp cache to
strengthen resistance to replay attacks. When there is a very large
number of nodes on the same link, or when a cache filling attack is
in progress, it is possible that the cache holding the most recent
timestamp per sender will become full. In this case, the node MUST
remove some entries from the cache or refuse some new requested
entries. The specific policy as to which entries are preferred over
others is left as an implementation decision.
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3.5. Negotiation Procedures
A negotiation initiator sends a negotiation request to discovered
negotiation counterpart devices, which may be different according to
different negotiation objectives. It may request relevant
information from the negotiation counterpart so that it can decide
its local configuration to give the most coordinated performance. It
may request the he negotiation counterpart to make a matching
configuration in order to set up a successful communication with it.
It may request certain simulation/forecast result by sending some dry
run conditions.
Beyond the traditional yes/no answer, the negotiation counterpart
should be able to reply with suggestion of change condition in the
negative scenario. This is going to start a bi-direction negotiation
towards reaching a compromise between the two network devices.
The negotiation procedures is ended when one of the negotiation peer
sends a Negotiation Ending message, which contains accept or decline
option and do not need response from negotiation peer any more.
4. CNP Constants
o ALL_CNP_NEIGHBOR (TBD1)
A link-local scope multicast address used by a CNP-enabled router
to discover CNP-enabled neighbor (i.e., on-link) devices . All
routers that support CNP are members of this multicast group.
* IPv6 mutlicast address: TBD1
* IPv4 multicast address: TBD2
o CNP Listen Port (TBD3)
A UDP port that every CNP-enabled network device always listens
to.
5. Device Identifier and Certificate Tag
A CNP-enabled Device should generated a public/private key pair. The
device then uses the public key as its identifier, which is
cryptographic in nature. is used to identify different devices. It
is a CNP unique identifier for a CNP participant.
It then gets a certificate for this public key, signed by a
Certificate Authority that is trusted by other network devices. The
Certificate Authority SHOULD be managed by the network administrator,
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to avoid needing to trust a third party. The signed certificate
would be used for authentication of the messasge sender.
A 128-bit Device Certifcate Tag, which is generated by taking a
cryptographic hash over the device certificate, is a short
presentation for CNP messages. It is the index key to find the
device certificate in a recepient's local trust certificate record.
The tag value is by taking SHA-1 hash algorithm over the
correspondent device certificate and taking the leftmost 128 bits of
the hash result.
6. Session Identifier
A 24-bit opaque value used to distinguish multiple sessions between
the same two devices. A new session ID SHOULD be generated for every
new Request message. All followup messages in the same negotiation
procedure, which is initiated by the request message, SHOULD carry
the same session identifier.
The session identifier SHOULD have low collision rate locally. It is
RECOMMENDED to be generated by a pseudo random algorithm.
7. CNP Messages
This document defines the following CNP message format and types.
Message types not listed here are reserved for future use. The
numeric encoding for each message type is shown in parentheses.
7.1. CNP Messsage Format
All CNP messages share an identical fixed format header and a vaiable
format area for options. Every Message carreis the Device
Certificate Tag of its sender and a session ID. Options are
presented serially in the options field, with no padding between the
options. Options are byte-aligned.
The following diagram illustrates the format of CNP messages:
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MESSAGE_TYPE | Session ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Device Certificate Tag |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Options (variable length) |
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
MESSAGE_TYPE Identifies the CNP message type. 8-bit.
Session ID Identifies this negotiation session, as defined in
Section 6. 24-bit.
Device Certificate Tag
Present the Device Certificate, which identifies
the negotiation deviceas, as defined in Section 5.
The Device Certificate Tag is 128 bit, also defined
in Section 5. It is used as index key to find the
device certificate.
Options CNP Options carried in this message. Options are
definded in Section 8.
7.2. Request Message
REQUEST (1) A negotiation requesting node sends a REQUEST message
to initiate a negotiation.
If the requesting node does not know any negotiation
counterpart, it sends the REQUEST messages to the
link-local ALL_CNP_NEIGHBOR multicast address.
If the requesting node reopen to a known negotiation
counterpart, it sends the REQUEST message to the
unicast address of the negotiation counterparts
directly.
7.3. Negotiation Message
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NEGOTIATION (2)A negotiation counterpart sends an NEGOTIATION
message in response to a REQUEST message or a
Negotiation message in a negotiation process which
may need multiple steps.
7.4. Negotiation-ending Message
NEGOTIATION-ENDING (3)
A negotiation counterpart sends an NEGOTIATION-EDNING
message to close the negotiation. It MUST contain
one, but only one of accept/decline/divert option,
defined in Section 8. It could be sent either by the
requesting node or the responding node.
7.5. Confirm-waiting Message
CONFIRM-WAITING (4)
A responding node sends a CONFIRM-WAITING message to
indicate the requesting node to wait for the further
negotiation response. It may because that the local
process need more time or the negotiation is
depending on another triggered negotiation. This
message MUST NOT include any other options than the
WAITING option defined in Section 8.5.
8. CNP General Options
This section defines the CNP general option for the negotiation
protocol signalling. Option type 10~64 is reserved for CNP general
options defined in the future.
8.1. Format of CNP Options
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| option-code | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| option-data |
| (option-len octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Option-code An unsigned integer identifying the specific option
type carried in this option.
Option-len An unsigned integer giving the length of the
option-data field in this option in octets.
Option-data The data for the option; the format of this data
depends on the definition of the option.
CNP options are scoped by using encapsulation.
8.2. Divert Option
The divert option is used to redirect a CNP request to another node,
which may be more proper for the intended negotiation. It may
redirect to an entity that is known as a specific negotiation
counterpart or a default gateway or a hierarchically upstream
devices. The divert option MUST be only encapsulated in Negotiation-
ending messages.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_DIVERT | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Locator Option (s) of Diverted Device(s) |
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Option-code OPTION_DIVERT (1).
Option-len The length of diverted desitination sub option(s)
in octets.
Locator Option (s) of Diverted Device
Locator Option(s),defined in Section 8.8,that point
to diverted destination device(s).
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8.3. Accept Option
The accept option is used to indicate the negotiation counterpart
that the proposed negotiation content is accepted.
The accept option MUST be only encapsulated in Negotiation-ending
messages.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_ACCEPT | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Option-code OPTION_ACCEPT (2).
Option-len 0.
8.4. Decline Option
The decline option is used to indicate the negotiation counterpart
the proposed negotiation content is declined and end the negotiation
process.
The decline option MUST be only encapsulated in Negotiation-ending
messages.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_DECLINE | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Option-code OPTION_DECLINE (3).
Option-len 0.
Notes: there are scenarios that a negotiation counterpart wants to
decline the proposed negotiation content and continue negotiation
process. For these scenarios, the negotiation counterpart SHOULD use
Response message, with either an objective option that contains at
least one all-1 or a specific decline objective option that provides
further condition for convergence.
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8.5. Waiting Time Option
The waiting time option is used to indicate the negotiation
counterpart to wait for the further negotiation response, since the
processing might need more time than usual or it might depend on
another triggered negotiation.
The waiting time option MUST be only encapsulated in Confirm-waiting
messages.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_WAITING | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Time |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Option-code OPTION_WAITING (4).
Option-len 4, in octets.
Time The time is counted in millisecond as a unit.
8.6. Certificate Option
The Certificate option carries the certificate of the sender. The
format of the Certificate option is described as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION Certificate | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. Certificate (variable length) .
. .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Option-code OPTION_CERT_PARAMETER (5)
Option-len Length of certificate in octets
Public key A variable-length field containing certificate
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8.7. Signature Option
The Signature option allows public key-based signatures to be
attached to a CNP message. The Signature option could be any place
within the CNP message. It protects the entire CNP header and
options. A TimeStamp has been integrated in the Signature Option for
anti-replay protection. The format of the Signature option is
described as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_SIGNATURE | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| HA-id | SA-id |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timestamp (64-bit) |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. Signature (variable length) .
. .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Option-code OPTION_SIGNATURE (6)
Option-len 12 + Length of Signature field in octets.
HA-id Hash Algorithm id. The hash algorithm is used for
computing the signature result. This design is
adopted in order to provide hash algorithm agility.
The value is from the Hash Algorithm for CNP
registry in IANA. The initial values are assigned
for SHA-1 is 0x0001.
SA-id Signature Algorithm id. The signature algorithm is
used for computing the signature result. This
design is adopted in order to provide signature
algorithm agility. The value is from the Signature
Algorithm for CNP registry in IANA. The initial
values are assigned for RSASSA-PKCS1-v1_5 is
0x0001.
Timestamp The current time of day (NTP-format timestamp
[RFC5905] in UTC (Coordinated Universal Time), a
64-bit unsigned fixed-point number, in seconds
relative to 0h on 1 January 1900.). It can reduce
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the danger of replay attacks.
Signature A variable-length field containing a digital
signature. The signature value is computed with
the hash algorithm and the signature algorithm, as
described in HA-id and SA-id. The signature
constructed by using the sender's private key
protects the following sequence of octets:
1. The CNP message header.
2. All CNP options including the Signature option
(fill the signature field with zeroes).
The signature filed MUST be padded, with all 0, to
the next octet boundary if its size is not an even
multiple of 8 bits. The padding length depends on
the signature algorithm, which is indicated in the
SA-id field.
8.8. Locator Options
These locator options are used to present device's or interface's
reachability informations. They are Locator IPv4 Address Option,
Locator IPv6 Address Option and Locator FQDN (Fully Qualified Domain
Name) Option.
8.8.1. Locator IPv4 address option
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_LOCATOR_IPV4ADDR | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4-Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Option-code OPTION_LOCATOR_IPV4ADDR (7)
Option-len 4, in octets.
IPv4-Address The IPv4 address locator of the device/interface.
8.8.2. Locator IPv6 address option
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_LOCATOR_IPV6ADDR | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| IPv6-Address |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Option-code OPTION_LOCATOR_IPV6ADDR (8).
Option-len 16, in octets.
IPv6-Address The IPv6 address locator of the device/interface.
Note: link-local IPv6 address SHOULD be avoided when this option is
used in the Divert option. It may create connect problem.
8.8.3. Locator FQDN option
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_FQDN | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Fully Qualified Domain Name |
| (variable length) |
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Option-code OPTION_FQDN (9).
Option-len Lenght of Fully Qualified Domain Name in octets.
Domain-Name The Fully Qualified Domain Name of the entity.
9. Objective Options and Considerations
The Objective options contains negotiation objectives, which are
various according to different functions/services. They MUST be
carried by Request or Negotiation Messages only. Objective options
SHOULD be signed the option type from 65 in the CNP option table.
For most scenarios, there SHOULD be initial values in the negotiation
requests. Consequently, the Objective options SHOULD always be
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completely presented in a Request message. If there is no initial
value, all 1 SHOULD be filled in.
9.1. Organizing of CNP Option
Naturally, a negotiation objective, which is based on a specific
service or function or action, SHOULD be organized as a CNP option.
It is NOT RECOMMENDED to organize multiple negotiation objectives
into a single option.
A negotiation objective may have multiple parameters. Parameters can
be categorized into two class: the obligatory are presented as fixed
fields; and the optional are presented in TLV sub-options. It is NOT
RECOMMENDED to split parameters in a same objective into multiple
options, unless they have different response periods. The exception
scenario may also be described by split objectives.
9.2. Vendor Specific Options
Option codes 128~159 have been reserved for vendor specific options.
Multiple option codes have been assigned because a single vendor may
use multiple options simultaneously. These vendor specific options
are highly likely to have different meanings when used by different
vendors.
9.3. Experimental Options
Option code 176~191 have been reserved for experimental options.
Multiple option codes have been assigned because a single experiment
may use multiple options simultaneously.
10. Items for Future Work
There are a few open design questions that are worthy of more work in
the near future, as listed below:
o UDP vs TCP: For now, this specification has chosen UDP as message
transport mechanism. However, this is not closed yet. UDP is
good for short conversation, fitting the divert scenarios well.
However, it may have issues with large packets. TCP is good for
stable and long sessions, with a little bit of time comsumption
during the session establishment stage.
o Message encryption: should CNP messages be encrypted as well as
signed, to protect against internal eavesdropping within the
network?
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o TLS vs built-in security mechanism. For now, this specifcation
has chosen a PKI based build-in security mechanism. However, TLS
may be chosen as security infrastructure for simplification
reasons.
o Use case. A use case may help readers to understand the
applicability of this specification. However, the authors have
not yet decided whether to have a separate document or have it in
this document.
o Rules about how data items are defined in a negotiation objective.
Maybe a formal information model is needed.
11. Security Considerations
Using certificate-based security mechanism and its verification
mechanism in CNP message exchanging provides the authentication and
data integrity protection. Timestamp mechanism provides anti-replay
function.
Since CNP is intended to be deployed in a single administrative
domain recommended to operate its own CA, there is no need for a
trusted third party.
12. IANA Considerations
Section 4 defines the following mtwpulticast addresses, which have
been assigned by IANA for use by CNP:
ALL_CNP_NEIGHBOR mutlicast address (IPv6): (TBD1)
ALL_CNP_NEIGHBOR mutlicast address (IPv4): (TBD2)
Section 4 defines the following UDP port, which have been assigned by
IANA for use by CNP:
CNP Listen Port: (TBD3)
This document defined a new Configuration Negotiation Protocol. The
IANA is requested to create a new CNP registry. The IANA is also
requested to add two new registry tables to the newly-created CNP
registry. The two tables are the CNP Messages table and CNP Options
table.
Initial values for these registries are given below. Future
assignments are to be made through Standards Action or Specification
Required [RFC5226]. Assignments for each registry consist of a name,
a value and a RFC number where the registry is defined.
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CNP Messages table. The values in this table are 16-bit unsigned
integers. The following initial values are assigned in Section 7 in
this document:
Type | Name | RFCs
---------+-----------------------------+------------
0 |Reserved | this document
1 |Request Message | this document
2 |Negotiation Message | this document
3 |Negotiation-end Message | this document
4 |Confirm-waiting Message | this document
CNP Options table. The values in this table are 16-bit unsigned
integers. The following initial values are assigned in Section 8 and
Section 9 in this document:
Type | Name | RFCs
---------+-----------------------------+------------
0 |Reserved | this document
1 |Divert Option | this document
2 |Accept Option | this document
3 |Decline Option | this document
4 |Waiting Time Option | this document
5 |Certificate Option | this document
6 |Sigature Option | this document
7 |Device IPv4 Address Option | this document
8 |Device IPv6 Address Option | this document
9 |Device FQDN Option | this document
10~64 |Reserved for future CNP | this document
|General Options |
128~159 |Vendor Specific Options | this document
176~191 |Experimental Options | this document
The IANA is also requested to create two new registry tables to the
CNP Parameters registry. The two tables are the Hash Algorithm for
CNP table and the Signature Algorithm for CNP table.
Initial values for these registries are given below. Future
assignments are to be made through Standards Action or Specification
Required [RFC5226]. Assignments for each registry consist of a name,
a value and a RFC number where the registry is defined.
Hash Algorithm for CNP. The values in this table are 16-bit unsigned
integers. The following initial values are assigned for Hash
Algorithm for CNP in this document:
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Name | Value | RFCs
---------------------+-----------+------------
Reserved | 0x0000 | this document
SHA-1 | 0x0001 | this document
SHA-256 | 0x0002 | this document
Signature Algorithm for CNP. The values in this table are 16-bit
unsigned integers. The following initial values are assigned for
Signature Algorithm for CNP in this document:
Name | Value | RFCs
---------------------+-----------+------------
Reserved | 0x0000 | this document
RSASSA-PKCS1-v1_5 | 0x0001 | this document
13. Acknowledgements
Valuable comments were received from Zhenbin Li and Dacheng Zhang,
and other participants in the xxx working group.
This document was produced using the xml2rfc tool [RFC2629].
14. Change log [RFC Editor: Please remove]
draft-jiang-config-negotiation-protocol-00: original version,
2013-10-19.
15. References
15.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
Housley, R., and W. Polk, "Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 5280, May 2008.
15.2. Informative References
[I-D.jiang-config-negotiation-ps]
Jiang, S., Yin, Y., and B. Carpenter, "Network
Configuration Negotiation Problem Statement and
Requirements", draft-jiang-config-negotiation-ps-02 (work
in progress), January 2014.
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[RFC2629] Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629,
June 1999.
[RFC4270] Hoffman, P. and B. Schneier, "Attacks on Cryptographic
Hashes in Internet Protocols", RFC 4270, November 2005.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008.
[RFC5905] Mills, D., Martin, J., Burbank, J., and W. Kasch, "Network
Time Protocol Version 4: Protocol and Algorithms
Specification", RFC 5905, June 2010.
Authors' Addresses
Sheng Jiang
Huawei Technologies Co., Ltd
Q14, Huawei Campus
No.156 Beiqing Road
Hai-Dian District, Beijing 100095
P.R. China
Email: jiangsheng@huawei.com
Brian Carpenter
Department of Computer Science
University of Auckland
PB 92019
Auckland 1142
New Zealand
Email: brian.e.carpenter@gmail.com
Bing Liu
Huawei Technologies Co., Ltd
Q14, Huawei Campus
No.156 Beiqing Road
Hai-Dian District, Beijing 100095
P.R. China
Email: leo.liubing@huawei.com
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Yuanbin Yin
Huawei Technologies Co., Ltd
Q15, Huawei Campus, No.156 Beiqing Road
Hai-Dian District, Beijing, 100095
P.R. China
Email: yinyuanbin@huawei.com
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