Network Working Group Dan Li Internet Draft Huawei Updates: RFC4204 D. Ceccarelli Category: Standards Track Ericsson Expires: September 2011 March 14, 2011 Behavior Negotiation in The Link Management Protocol draft-ietf-ccamp-lmp-behavior-negotiation-02.txt Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html This Internet-Draft will expire on September 13, 2011. Copyright Notice Copyright (c) 2010 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 to this document. Code Components extracted from this document must include Simplified BSD License text as described in Li. et al. Expires September 2011 [Page 1]
draft-ietf-ccamp-lmp-behavior-negotiation-02.txt March 2011 Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Abstract The Link Management Protocol (LMP) is used to coordinate the properties, use, and faults of data links in Generalized Multiprotocol Label Switching (GMPLS) networks. Various proposals have been advanced to provide extensions to the base LMP specification. This document defines an extension to negotiate capabilities and support for those extensions, and provides a generic procedure for LMP implementations that do not recognize or do not support any one of these extensions. Conventions used in this document 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]. Table of Contents 1. Introduction ................................................ 2 2. LMP Behavior Negotiation Procedure........................... 3 3. Backward Compatibility....................................... 5 4. Security Considerations...................................... 6 5. IANA Considerations ......................................... 6 5.1. New LMP Class Type...................................... 6 5.2. New Capabilities Registry............................... 7 6. Contributors ................................................ 7 7. Acknowledgments ............................................. 8 8. References .................................................. 8 8.1. Normative References.................................... 8 8.2. Informative References.................................. 8 9. Authors' Addresses .......................................... 9 1. Introduction The Link Management Protocol (LMP) [RFC4204] has been successfully deployed in Generalized Multiprotocol Label Switching (GMPLS)- controlled networks. New LMP behaviors and protocol extensions have been introduced in a number of IETF documents as set out later in this section. It is likely that future extensions will be made to support additional functions. Li. et al. Expires September 2011 [Page 2]
draft-ietf-ccamp-lmp-behavior-negotiation-02.txt March 2011 In the network, if one GMPLS Label Switch Router (LSR) supports a new behavior or protocol extension, but its peer LSR does not, it is necessary to have a protocol mechanism for resolving issues that may arise. It is also beneficial to have a protocol mechanism to discover the capabilities of peer LSRs so that the right protocol extensions can be selected and the correct features enabled. There are no such procedures defined in the base LMP specification [RFC4204], so this document defines how to handle LMP extensions both at legacy LSRs and at upgraded LSRs that would communicate with legacy LSRs. In [RFC4204], the basic behaviors have been defined around the use of the standard LMP messages, which include Config, Hello, Verify, Test, LinkSummary, and ChannelStatus. Per [RCF4204], these behaviors MUST be supported when LMP is implemented, and the message types from 1 to 20 have been assigned by IANA for these messages. In [RFC4207], the SONET/SDH technology-specific behavior and information for LMP is defined. The Trace behavior is added to LMP, and the message types from 21 to 31 were assigned by IANA for the messages that provide the TRACE function. The Trace function has been extended for the support of OTNs (Optical Transport Networks) in [LMP-TEST]. In [RFC4209], extensions to LMP are defined to allow it to be used between a peer node and an adjacent Optical Line System (OLS). The LMP object class type and sub-object class name have been extended to support DWDM behavior. In [RFC5818], the data channel consistency check behavior is defined, and the message types from 32 to 34 have been assigned by IANA for messages that provide this behavior. It is likely that future extensions to LMP for other functions or technologies will require the definition of further LMP messages. This document describes the behavior negotiation procedure to make sure both LSRs at the ends of each link understand the LMP messages that they exchange. 2. LMP Behavior Negotiation Procedure The Config message is used in the control channel negotiation phase of LMP [RFC4204]. The LMP behavior negotiation procedure is defined in this document as an addition to this phase. Li. et al. Expires September 2011 [Page 3]
draft-ietf-ccamp-lmp-behavior-negotiation-02.txt March 2011 The Config message is defined in Section 12.3.1 of [RFC4204] and carries the <CONFIG> object (class name 6) as defined in Section 13.6 of [RFC4204]. Two class types have been defined: - C-Type = 1, HelloConfig, defined in [RFC4204] - C-Type = 2, LMP_WDM_CONFIG, defined in [RFC4209] This document defines a third C-Type with value 3 (TBD by IANA) to report and negotiate currently defined LMP mechanisms and behaviors, and to allow future LMP extensions to be reported and negotiated. - C-Type = 3, BEHAVIOR_CONFIG The format of the new type of CONFIG Class is defined 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Length |B|S|D|C| Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Length: 8 bits This field indicates the total length of the objects expressed in multiples of 4 bytes. Flags: B: 1 bit This bit indicates support for the basic behaviors defined in [RFC4204]. S: 1 bit This bit indicates support for the Trace behavior of SONET/SDH technology-specific defined in [RFC4207]. D: 1 bit This bit indicates support for the DWDM behavior defined in [RFC4209]. Li. et al. Expires September 2011 [Page 4]
draft-ietf-ccamp-lmp-behavior-negotiation-02.txt March 2011 C: 1 bit This bit indicates support for the data channel consistency check behavior defined in [RFC5818]. Further bits may be defined in future documents. The Reserved field MUST be sent as zero and MUST NOT be ignored on receipt. This allows the detection of unsupported or unknown LMP behaviors when new bits are allocated to indicate further capabilities and are sent as one. Upon receiving a bit set related to an unsupported or unknown behavior, a ConfigNack message MUST be sent with a <CONFIG> object, the BEHAVIOR_CONFIG C-Type representing the supported LMP behaviors. An LSR receiving such a ConfigNack SHOULD select a supported set of capabilities and send a further Config message, or MAY raise an alert to the management system (or log an error) and stop trying to perform LMP communications with its neighbor. Note that multiple <CONFIG> objects (each with a different Class Type) MAY be present on a Config message in which case all of the objects SHOULD be processed, but see the note on backward compatibility in the next section. However, if more than one <CONFIG> object with the same Class Type is present on a Config message, the message SHOULD be rejected. 3. Backward Compatibility An LSR that receives a Config message containing a <CONFIG> object with a C-Type that it does not recognize should respond with a ConfigNack message as described in [RFC4204]. Thus, legacy LMP nodes that do not support the BEHAVIOR_CONFIG C-Type defined in this document will respond with a ConfigNack message. Note that [RFC4204] does not describe how multiple <CONFIG> objects with different C-Types should be processed. Thus it is possible that a legacy node receiving a BEHAVIOR_CONFIG object on a Config message that also includes a HelloConfig or LMP_WDM_CONFIG object might react as follows: - Reject the message because of the unknown BEHAVIOR_CONFIG object as described above. Li. et al. Expires September 2011 [Page 5]
draft-ietf-ccamp-lmp-behavior-negotiation-02.txt March 2011 - Reject the message because of multiple <CONFIG> objects. This achieves the same effective result. - Ignore the second <CONFIG> object. This would result in the BEHAVIOR_CONFIG object being unprocessed and also not rejected. An LSR that receives a ConfigNack message rejecting a Config message that it sent containing the BEHAVIOR CONFIG C-Type because that object variant is not supported by its peer MUST NOT draw any conclusions about the level of support at the peer for LMP options described by bits B, S, D, and C. Instead, the LSR MUST revert to current practices of configuration or discovery through attempts to exercise the options. However, as future documents are published describing new LMP features, and those documents require support of the BEHAVIOR CONFIG C-Type, an LSR that receives a ConfigNack message rejecting a Config message that it sent containing the BEHAVIOR CONFIG C-Type because that object variant is not supported by its peer SHOULD conclude that the additional options it wants to use are not supported by the peer. 4. Security Considerations [RFC4204] describes how LMP messages between peers can be secured, and these measures are equally applicable to messages carrying the new <CONFIG> object defined in this document. The operation of the procedures described in this document does not of itself constitute a security risk since they do not cause any change in network state. It would be possible, if the messages were intercepted or spoofed to cause bogus alerts in the management plane, or to cause LMP peers to consider that they could or could not operate protocol extensions, and so the use of the LMP security measures are RECOMMENDED. 5. IANA Considerations 5.1. New LMP Class Type IANA maintains the "Link Management Protocol (LMP)" registry which has a subregistry called "LMP Object Class name space and Class type (C-Type)". Li. et al. Expires September 2011 [Page 6]
draft-ietf-ccamp-lmp-behavior-negotiation-02.txt March 2011 IANA is requested to make an assignment from this registry as follows: 6 CONFIG [RFC4204] CONFIG Object Class type name space: C-Type Description Reference ------ ------------------------ --------- 3 BEHAVIOR_CONFIG [This.I-D] 5.2. New Capabilities Registry IANA is requested to create a new subregistry of the "Link Management Protocol (LMP)" registry to track the Behaviour Configuration bits defined in Section 2 of this document. It is suggested that this registry be called "LMP Behaviour Configuration Flags". Allocations from this registry are by Standards Action. Bits in this registry are numbered from zero as the most significant bit (transmitted first). The number of bits that can be present is limited by the length field of the <CONFIG> object which gives rise to (255 x 32)-8 = 8152. IANA is strongly recommended to allocate new bits with the lowest available unused number. The registry is initially populated as follows: Bit | Bit | Meaning | Reference Number | Name | | -------+------+----------------------------------------+---------- 0 | B | Basic LMP behavior support | [This.ID] 1 | S | SONET/SDH Test support | [This.ID] 2 | D | DWDM support | [This.ID] 3 | C | Data Channel consistency check support | [This.ID] 6. Contributors Diego Caviglia Ericsson Via A. Negrone 1/A 16153 Genoa Italy Phone: +39 010 600 3736 Email: diego.caviglia@ericsson.com Li. et al. Expires September 2011 [Page 7]
draft-ietf-ccamp-lmp-behavior-negotiation-02.txt March 2011 7. Acknowledgments Thanks to Adrian Farrel and Lou Berger for their useful comments. 8. References 8.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC4204] J. Lang, Ed., "Link Management Protocol (LMP)", RFC 4204, October 2005. [RFC4207] J. Lang, Ed., "Synchronous Optical Network (SONET)/ Synchronous Digital Hierarchy (SDH) Encoding for Link Management Protocol (LMP) Test Messages", RFC 4207, October 2005. [RFC4209] A. Fredette, Ed., "Link Management Protocol (LMP) for Dense Wavelength Division Multiplexing (DWDM) Optical Line Systems", RFC 4209, October 2005. [RFC5818] D. Li, Ed., "Data Channel Status Confirmation Extensions for the Link Management Protocol", RFC 5818, April 2010. 8.2. Informative References [LMP TEST] D. Ceccarelli, Ed., "Link Management Protocol (LMP) Test Messages Extensions for Evolutive Optical Transport Networks (OTN)" draft-ceccarelli-ccamp-gmpls-g709-lmp- test-02.txt, May, 2010. Li. et al. Expires September 2011 [Page 8]
draft-ietf-ccamp-lmp-behavior-negotiation-02.txt March 2011 9. Authors' Addresses Dan Li Huawei Technologies F3-5-B R&D Center, Huawei Industrial Base, Shenzhen 518129 China Phone: +86 755-289-70230 Email: danli@huawei.com Daniele Ceccarelli Ericsson Via A. Negrone 1/A Genova - Sestri Ponente Italy Email: daniele.ceccarelli@ericsson.com Li. et al. Expires September 2011 [Page 9]
