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diff --git a/doc/rfc/rfc6898.txt b/doc/rfc/rfc6898.txt new file mode 100644 index 0000000..5ff854b --- /dev/null +++ b/doc/rfc/rfc6898.txt @@ -0,0 +1,619 @@ + + + + + + +Internet Engineering Task Force (IETF) D. Li +Request for Comments: 6898 Huawei +Updates: 4204, 4207, 4209, 5818 D. Ceccarelli +Category: Standards Track Ericsson +ISSN: 2070-1721 L. Berger + LabN + March 2013 + + + Link Management Protocol Behavior Negotiation and + Configuration Modifications + +Abstract + + The Link Management Protocol (LMP) is used to coordinate the + properties, use, and faults of data links in networks controlled by + Generalized Multiprotocol Label Switching (GMPLS). This document + defines an extension to LMP to negotiate capabilities and indicate + support for LMP extensions. The defined extension is compatible with + non-supporting implementations. + + This document updates RFC 4204, RFC 4207, RFC 4209, and RFC 5818. + +Status of This Memo + + This is an Internet Standards Track document. + + This document is a product of the Internet Engineering Task Force + (IETF). It represents the consensus of the IETF community. It has + received public review and has been approved for publication by the + Internet Engineering Steering Group (IESG). Further information on + Internet Standards is available in Section 2 of RFC 5741. + + Information about the current status of this document, any errata, + and how to provide feedback on it may be obtained at + http://www.rfc-editor.org/info/rfc6898. + + + + + + + + + + + + + + + +Li, et al. Standards Track [Page 1] + +RFC 6898 LMP Behavior Negotiation March 2013 + + +Copyright Notice + + Copyright (c) 2013 IETF Trust and the persons identified as the + document authors. All rights reserved. + + This document is subject to BCP 78 and the IETF Trust's Legal + Provisions Relating to IETF Documents + (http://trustee.ietf.org/license-info) in effect on the date of + publication of this document. Please review these documents + carefully, as they describe your rights and restrictions with respect + to this document. Code Components extracted from this document must + include Simplified BSD License text as described in Section 4.e of + the Trust Legal Provisions and are provided without warranty as + described in the Simplified BSD License. + +Table of Contents + + 1. Introduction ....................................................3 + 1.1. Conventions Used in This Document ..........................4 + 2. LMP Message Modifications .......................................4 + 2.1. Modified Message Formats ...................................4 + 2.2. Processing .................................................5 + 3. LMP Behavior Negotiation ........................................6 + 3.1. BehaviorConfig C-Type Format ...............................6 + 3.2. Processing .................................................7 + 4. Backward Compatibility ..........................................7 + 5. Security Considerations .........................................8 + 6. IANA Considerations .............................................9 + 6.1. New LMP Class Type .........................................9 + 6.2. New Capabilities Registry ..................................9 + 7. Normative References ...........................................10 + 8. Acknowledgments ................................................10 + 9. Contributors ...................................................10 + + + + + + + + + + + + + + + + + + +Li, et al. Standards Track [Page 2] + +RFC 6898 LMP Behavior Negotiation March 2013 + + +1. Introduction + + The Link Management Protocol (LMP) [RFC4204] has been successfully + deployed in networks controlled by Generalized Multiprotocol Label + Switching (GMPLS). + + 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. + + In a network, if one LMP-capable node supports a new behavior or + protocol extension but its adjacent node does not, it is beneficial + to have a protocol mechanism to discover the capabilities of peer + nodes so that the right protocol extensions can be selected and the + correct features can be enabled. There are no such procedures + defined in the base LMP specification [RFC4204]. [RFC4209] defined a + specific mechanism to identify support for the functions specified in + that document. This document defines an LMP extension to support the + identification of supported LMP functions in a generic fashion, as + well as how a node supporting these extensions would communicate with + legacy nodes. + + 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 [RFC4204], 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. Support for all + functions required by [RFC4204] is assumed by this document. + + 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 have been assigned by IANA for + the messages that provide the Trace function. + + 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 subobject class name have been extended to + support Dense Wavelength Division Multiplexing (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. + + + + + +Li, et al. Standards Track [Page 3] + +RFC 6898 LMP Behavior Negotiation March 2013 + + + This document describes an LMP extension, referred to as behavior + negotiation, that enables the nodes at the ends of a link to identify + the LMP messages and functions supported by the adjacent node. The + extension makes use of a new CONFIG object. The use of this new + object does not preclude the use of existing or yet to be defined + CONFIG objects. + + This document also modifies the format of messages that carry the + CONFIG object to allow for multiple objects. Multiple CONFIG objects + allow behavior negotiation concurrent with existing usage of the + CONFIG object, i.e., HelloConfig C-Type defined in [RFC4204] and + LMP-WDM_CONFIG C-Type defined in [RFC4209]. This document modifies + the ConfigAck message to include CONFIG objects so that acceptable + parameters are explicitly identified. It also describes how a node + that supports the extensions defined in this document interacts with + a legacy LMP-capable node. + +1.1. 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]. + +2. LMP Message Modifications + + LMP Config, ConfigNack, and ConfigAck messages are modified by this + document to allow for the inclusion of multiple CONFIG objects. The + Config and ConfigNack messages were only defined to carry one CONFIG + object in [RFC4204]. The ConfigAck message, which was defined + without carrying any CONFIG objects in [RFC4204], is modified to + enable explicit identification of negotiated configuration + parameters. The inclusion of CONFIG objects in ConfigAck messages is + triggered by the use of the BehaviorConfig object (defined below) in + a received Config message. + + The message formats in the sections that follow use Backus-Naur Form + (BNF) encoding as defined in [RFC5511]. + +2.1. Modified Message Formats + + The format of the Config message as updated by this document is as + follows: + <Config Message> ::= <Common Header> <LOCAL_CCID> <MESSAGE_ID> + <LOCAL_NODE_ID> <CONFIG> [ <CONFIG> ... ] + + + + + + + +Li, et al. Standards Track [Page 4] + +RFC 6898 LMP Behavior Negotiation March 2013 + + + The format of the ConfigAck message as updated by this document is as + follows: + + <ConfigAck Message> ::= <Common Header> <LOCAL_CCID> <LOCAL_NODE_ID> + <REMOTE_CCID> <MESSAGE_ID_ACK> + <REMOTE_NODE_ID>[ <CONFIG> ... ] + + The format of the ConfigNack message as updated by this document is + as follows: + + <ConfigNack Message> ::= <Common Header> <LOCAL_CCID> + <LOCAL_NODE_ID> <REMOTE_CCID> + <MESSAGE_ID_ACK> <REMOTE_NODE_ID> + <CONFIG> [ <CONFIG> ... ] + +2.2. Processing + + Nodes that support the extensions defined in this document MAY + include multiple CONFIG objects when sending a Config, ConfigAck, and + ConfigNack message. A maximum of a single object of any particular + C-type SHALL be included. A node that receives a message with + multiple CONFIG objects of the same C-type SHALL process the first + object of a particular C-type and ignore any subsequent CONFIG + objects of the same C-type. Unless specified as part of the CONFIG + object definition, ordering of CONFIG objects with different C-type + values is not significant. + + Nodes that support the extensions defined in this document MUST + include a BehaviorConfig type object when sending a Config message to + a neighbor whose support for the extensions is either known or + unknown. When the neighbor is known to not support the extensions, + the object MUST NOT be sent. Inclusion of other CONFIG objects in a + Config message is at the discretion of the message sender and is + based on the rules defined as part of CONFIG object definition. + Nodes MAY include HelloConfig, LMP-WDM_CONFIG, BehaviorConfig object + types in a single message. + + Inclusion of multiple CONFIG objects in a ConfigNack message is based + on the processing of a received Config message. Per [RFC4204], + "Parameters where agreement was reached MUST NOT be included in the + ConfigNack Message." As such, a ConfigNack message MUST NOT include + CONFIG objects that are acceptable and MUST include any CONFIG + objects which are not acceptable. When a CONFIG object is included + in a ConfigNack message, per [RFC4204], the object is to include + "acceptable alternate values for negotiable parameters". + + + + + + +Li, et al. Standards Track [Page 5] + +RFC 6898 LMP Behavior Negotiation March 2013 + + + When sending a ConfigAck message, nodes supporting the extensions + defined in this document MUST include all CONFIG objects received in + the corresponding Config message when that message includes a CONFIG + object of type BehaviorConfig. + +3. LMP Behavior Negotiation + + 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. + + 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 to report and negotiate LMP + mechanisms and behaviors. Its usage indicates support for the + extensions defined in this document. + +3.1. BehaviorConfig C-Type Format + + Class = 6 + + - C-Type = 3, BehaviorConfig + + 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 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + |S|D|C| Must Be Zero (MBZ) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + Flags: + + 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. Standards Track [Page 6] + +RFC 6898 LMP Behavior Negotiation March 2013 + + + C: 1 bit + + This bit indicates support for the data channel consistency check + behavior defined in [RFC5818]. + + Must Be Zero (MBZ): Variable length + + The remaining bits in the flags field MUST be set to zero (0). + This field MUST be sized to ensure 32-bit alignment of the object. + + Other bits may be defined in future documents, in which case the + number of bits in the MBZ field is expected to change. + +3.2. Processing + + The inclusion of a BehaviorConfig type object in a message is + discussed above in Section 2.2. + + When sending a BehaviorConfig type object, the N-bit (negotiable) in + the LMP object header MUST be set (N=1) in the LMP object header. + + When sending a BehaviorConfig type object in Config and ConfigNack + messages, the flags field SHOULD be set based on the supported + capabilities of the sending node. When sending a ConfigAck message, + the flags field MUST be set to the value received in the + corresponding Config message. + + When receiving a BehaviorConfig type object, the node compares the + flags field against its capacities. Any bit set in the MBZ portion + of the flags field MUST be interpreted as unacceptable. Processing + related to unacceptable values in CONFIG objects is defined in + [RFC4204] and is not modified by this document. + +4. Backward Compatibility + + The required use of the BehaviorConfig type CONFIG object enables + nodes that support the extensions defined in this document to + explicitly identify when a neighboring node does not. When a non- + supporting node receives a Config message with the BehaviorConfig + type CONFIG object or multiple CONFIG objects, its behavior is to be + one of the following behaviors: + + a) Reject the Config message because of the unknown BehaviorConfig + object type and send a ConfigNack message which includes the + unsupported C-type. + + + + + + +Li, et al. Standards Track [Page 7] + +RFC 6898 LMP Behavior Negotiation March 2013 + + + b) Reject the message because of multiple CONFIG objects and send a + ConfigNack message which includes all but one of the CONFIG + objects. + + c) Silently ignore the one or more of the CONFIG object, and respond + with a ConfigAck message that does not include any CONFIG objects. + + d) Treat the message as malformed, and discard it without any + response. + + Behaviors (a) and (b) result in ConfigNack messages with a + BehaviorConfig type object whose contents are identical to what was + sent in the Config message. Behavior (c) results in a ConfigAck + message without a BehaviorConfig type CONFIG object. In each of + these cases, the node SHOULD explicitly identify that the LMP + neighbor does not support the extensions defined in this document. + + Behavior (d) results in no response at all. When the node reaches + the "retry limit", defined in [RFC4204], the node SHOULD infer that + the LMP neighbor does not support the extensions defined in this + document. + + Once a node identifies a neighbor as not supporting the extensions + defined in this document, the node SHOULD follow previously defined + Config message usage. + +5. 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. + + Alone, the procedures described in this document do not 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. + + Note, however, that [RFC4204] references for security have been + updated with [RFC4301], and the current reference for IKEv2 is + [RFC5996]. + + + + + + + + + +Li, et al. Standards Track [Page 8] + +RFC 6898 LMP Behavior Negotiation March 2013 + + +6. IANA Considerations + +6.1. New LMP Class Type + + IANA maintains the "Link Management Protocol (LMP) Parameters" + registry, which has a subregistry called "LMP Object Class name space + and Class type (C-Type)". + + IANA has made an assignment from this registry as follows: + + 6 CONFIG [RFC4204] + + CONFIG Object Class type name space: + + C-Type Description Reference + ------------ --------------------- --------- + 3 BehaviorConfig RFC 6898 + +6.2. New Capabilities Registry + + IANA has created a new subregistry of the "Link Management Protocol + (LMP) Parameters" registry to track the Behavior Configuration bits + defined in Section 2 of this document. This registry is called "LMP + Behavior 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 | S | SONET/SDH Test support | RFC 6898 + 1 | D | DWDM support | RFC 6898 + 2 | C | Data Channel consistency check support | RFC 6898 + + + + + + + + + + +Li, et al. Standards Track [Page 9] + +RFC 6898 LMP Behavior Negotiation March 2013 + + +7. Normative References + + [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate + Requirement Levels", BCP 14, RFC 2119, March 1997. + + [RFC4301] Kent, S. and K. Seo, "Security Architecture for the + Internet Protocol", RFC 4301, December 2005. + + [RFC5996] Kaufman, C., Hoffman, P., Nir, Y., and P. Eronen, + "Internet Key Exchange Protocol Version 2 (IKEv2)", RFC + 5996, September 2010. + + [RFC4204] Lang, J., Ed., "Link Management Protocol (LMP)", RFC 4204, + October 2005. + + [RFC4207] Lang, J. and D. Papadimitriou, "Synchronous Optical + Network (SONET)/Synchronous Digital Hierarchy (SDH) + Encoding for Link Management Protocol (LMP) Test + Messages", RFC 4207, October 2005. + + [RFC4209] Fredette, A., Ed., and J. Lang, Ed., "Link Management + Protocol (LMP) for Dense Wavelength Division Multiplexing + (DWDM) Optical Line Systems", RFC 4209, October 2005. + + [RFC5818] Li, D., Xu, H., Bardalai, S., Meuric, J., and D. Caviglia, + "Data Channel Status Confirmation Extensions for the Link + Management Protocol", RFC 5818, April 2010. + + [RFC5511] Farrel, A., "Routing Backus-Naur Form (RBNF): A Syntax + Used to Form Encoding Rules in Various Routing Protocol + Specifications", RFC 5511, April 2009. + +8. Acknowledgments + + Thanks to Adrian Farrel and Richard Graveman for their useful + comments. + +9. Contributors + + Diego Caviglia + Ericsson + Via E. Melen, 77 + Genova - Erzelli + Italy + Phone: +39 010 600 3736 + EMail: diego.caviglia@ericsson.com + + + + + +Li, et al. Standards Track [Page 10] + +RFC 6898 LMP Behavior Negotiation March 2013 + + +Authors' Addresses + + Dan Li + Huawei Technologies + F3-5-B R&D Center, Huawei Industrial Base, + Shenzhen 518129 + China + Phone: +86 755-289-70230 + EMail: huawei.danli@huawei.com + + Daniele Ceccarelli + Ericsson + Via E. Melen, 77 + Genova - Erzelli + Italy + EMail: daniele.ceccarelli@ericsson.com + + Lou Berger + LabN Consulting, L.L.C. + EMail: lberger@labn.net + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +Li, et al. Standards Track [Page 11] + |