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Versions: 00 01 02                                                      
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
   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 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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