--- 1/draft-ietf-teas-mpls-tp-rsvpte-ext-associated-lsp-00.txt 2015-02-08 11:14:52.595595218 -0800 +++ 2/draft-ietf-teas-mpls-tp-rsvpte-ext-associated-lsp-01.txt 2015-02-08 11:14:52.635596168 -0800 @@ -1,21 +1,21 @@ -CCAMP Working Group Fei Zhang, Ed. +TEAS Working Group Fei Zhang, Ed. Internet-Draft Huawei Intended status: Standards Track Ruiquan Jing -Expires: June 11, 2015 China Telecom +Expires: August 12, 2015 China Telecom Rakesh Gandhi, Ed. Cisco Systems - December 8, 2014 + February 8, 2015 RSVP-TE Extensions for Associated Bidirectional LSPs - draft-ietf-teas-mpls-tp-rsvpte-ext-associated-lsp-00 + draft-ietf-teas-mpls-tp-rsvpte-ext-associated-lsp-01 Abstract This document describes Resource reSerVation Protocol (RSVP) extensions to bind two point-to-point unidirectional Label Switched Paths (LSPs) into an associated bidirectional LSP. The association is achieved by defining new Association Types for use in ASSOCIATION and in Extended ASSOCIATION Objects. One of these types enables independent provisioning of the associated bidirectional LSPs on both sides, while the other enables single sided provisioning. The @@ -33,73 +33,76 @@ 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." Copyright Notice - Copyright (c) 2014 IETF Trust and the persons identified as the + Copyright (c) 2015 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 2. Conventions Used in This Document . . . . . . . . . . . . . . 4 2.1. Definitions . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1.1. Reverse Unidirectional LSPs . . . . . . . . . . . . . 4 - 3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 3.1. Provisioning Model Overview . . . . . . . . . . . . . . . 4 + 2.1.2. Message Formats . . . . . . . . . . . . . . . . . . . 4 + 3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 + 3.1. Provisioning Model Overview . . . . . . . . . . . . . . . 5 3.1.1. Single Sided Provisioning . . . . . . . . . . . . . . 5 3.1.2. Double Sided Provisioning . . . . . . . . . . . . . . 5 3.2. Association Signaling Overview . . . . . . . . . . . . . . 5 3.2.1. Single Sided Provisioning . . . . . . . . . . . . . . 6 3.2.2. Double Sided Provisioning . . . . . . . . . . . . . . 6 - 3.3. Asymmetric Bandwidth Signaling Overview . . . . . . . . . 6 - 3.3.1. Single Sided Provisioning . . . . . . . . . . . . . . 6 + 3.3. Asymmetric Bandwidth Signaling Overview . . . . . . . . . 7 + 3.3.1. Single Sided Provisioning . . . . . . . . . . . . . . 7 3.3.2. Double Sided Provisioning . . . . . . . . . . . . . . 7 3.4. Recovery LSP Overview . . . . . . . . . . . . . . . . . . 7 - 4. Message and Object Definitions . . . . . . . . . . . . . . . . 7 - 4.1. RSVP Message Formats . . . . . . . . . . . . . . . . . . . 7 + 4. Message and Object Definitions . . . . . . . . . . . . . . . . 8 + 4.1. RSVP Message Formats . . . . . . . . . . . . . . . . . . . 8 4.2. ASSOCIATION Object . . . . . . . . . . . . . . . . . . . . 8 4.3. Extended ASSOCIATION Object . . . . . . . . . . . . . . . 9 4.4. REVERSE_LSP Object Definition . . . . . . . . . . . . . . 9 4.4.1. REVERSE_LSP Object Format . . . . . . . . . . . . . . 9 4.4.2. REVERSE_LSP Subobjects . . . . . . . . . . . . . . . . 10 5. Processing Rules . . . . . . . . . . . . . . . . . . . . . . . 10 5.1. Rules For ASSOCIATION Object . . . . . . . . . . . . . . . 10 5.1.1. Compatibility For ASSOCIATION Object . . . . . . . . . 12 - 5.2. Rules For REVERSE_LSP Object . . . . . . . . . . . . . . . 12 + 5.2. Rules For REVERSE_LSP Object . . . . . . . . . . . . . . . 13 5.2.1. Compatibility For REVERSE_LSP Object . . . . . . . . . 13 5.3. Single Sided Associated Bidirectional LSP Setup and - Teardown . . . . . . . . . . . . . . . . . . . . . . . . . 13 + Teardown . . . . . . . . . . . . . . . . . . . . . . . . . 14 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14 6.1. Association Types . . . . . . . . . . . . . . . . . . . . 14 - 6.2. REVERSE_LSP Object . . . . . . . . . . . . . . . . . . . . 14 - 7. Security Considerations . . . . . . . . . . . . . . . . . . . 15 - 8. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 15 - 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 16 - 9.1. Normative References . . . . . . . . . . . . . . . . . . . 16 - 9.2. Informative References . . . . . . . . . . . . . . . . . . 16 - Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 18 + 6.2. REVERSE_LSP Object . . . . . . . . . . . . . . . . . . . . 15 + 6.3. Reverse LSP Failure PathErr Sub-code . . . . . . . . . . . 15 + 7. Security Considerations . . . . . . . . . . . . . . . . . . . 16 + 8. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 16 + 9. Contributing Authors . . . . . . . . . . . . . . . . . . . . . 16 + 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 17 + 10.1. Normative References . . . . . . . . . . . . . . . . . . 17 + 10.2. Informative References . . . . . . . . . . . . . . . . . 17 + Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19 1. Introduction The MPLS Transport Profile (MPLS-TP) requirements document [RFC5654] specifies that MPLS-TP MUST support associated bidirectional point- to-point Label Switched Paths (LSPs). These requirements are given in Section 2.1 (General Requirements), and are repeated below: 7. MPLS-TP MUST support associated bidirectional point-to-point LSPs. @@ -168,56 +172,61 @@ 2.1.1. Reverse Unidirectional LSPs Two reverse unidirectional LSPs are setup in the opposite directions between a pair of source and destination nodes to form an associated bidirectional LSP. A reverse unidirectional LSP originates on the same node where the forward unidirectional LSP terminates, and it terminates on the same node where the forward unidirectional LSP originates. +2.1.2. Message Formats + + This document uses the Routing Backus-Naur Form (RBNF) to define + message formats as defined in [RFC5511]. + 3. Overview 3.1. Provisioning Model Overview This section provides an overview and definition of the models for - provisioning bidirectional LSPs. + provisioning associated bidirectional LSPs. The associated bidirectional LSP's forward and reverse unidirectional LSPs are established, monitored, and protected independently as specified by [RFC5654]. Configuration information regarding the LSPs can be provided at one or both endpoints of the associated bidirectional LSP. Depending on the method chosen, there are two models of creating an associated bidirectional LSP; single sided provisioning, and double sided provisioning. 3.1.1. Single Sided Provisioning For the single sided provisioning, the Traffic Engineering (TE) tunnel is configured only on one endpoint. An LSP for this tunnel is initiated by the initiating endpoint with the (Extended) ASSOCIATION Object inserted in the Path message. The other endpoint then creates the corresponding reverse TE tunnel and signals the reverse LSP in - response. + response using information from the REVERSE_LSP Object if present. 3.1.2. Double Sided Provisioning For the double sided provisioning, two unidirectional TE tunnels are - configured independently on both endpoints. The LSPs for the tunnels - are signaled with (Extended) ASSOCIATION Objects inserted in the Path - message by both endpoints to indicate that the two LSPs are to be - associated to form a bidirectional LSP. + configured independently, one on each endpoint. The LSPs for the + tunnels are signaled with (Extended) ASSOCIATION Objects inserted in + the Path message by both endpoints to indicate that the two LSPs are + to be associated to form a bidirectional LSP. 3.2. Association Signaling Overview This section provides an overview of the association signaling - methods for the bidirectional LSPs. + methods for the associated bidirectional LSPs. Three scenarios exist for binding two unidirectional LSPs together to form an associated bidirectional LSP. These are: 1) Neither unidirectional LSP exists, and both must be established. 2) Both unidirectional LSPs exist, but the association must be established. 3) One LSP exists, but the reverse associated LSP must be established. In each of the situations described above, both provisioning models are applicable. @@ -242,57 +251,59 @@ Figure 1: An example of associated bidirectional LSP 3.2.1. Single Sided Provisioning For the single sided provisioning model, creation of reverse LSP1 is triggered by LSP2 or creation of reverse LSP2 is triggered by LSP1. When creation of reverse LSP2 is triggered by LSP1, LSP1 is provisioned first (or refreshed if LSP1 already exists) at node A. LSP1 is then signaled with an (Extended) ASSOCIATION Object inserted in the Path message, in which the Association Type indicating single - sided provisioning. Upon receiving this Path message for LSP1, node - B establishes reverse LSP2. The (Extended) ASSOCIATION Object - inserted in LSP2's Path message is the same as that received in - LSP1's Path message. + sided provisioning is included. Upon receiving this Path message for + LSP1, node B establishes reverse LSP2. The (Extended) ASSOCIATION + Object inserted in LSP2's Path message is the same as that received + in LSP1's Path message. A similar procedure is used if LSP2 is provisioned first at node B and the creation of reverse LSP1 is triggered by LSP2. In both cases, the two unidirectional LSPs are bound together to form an associated bidirectional LSP based on identical (Extended) ASSOCIATION Objects in the two LSPs' Path messages. 3.2.2. Double Sided Provisioning For the double sided provisioning model, both LSP1 and LSP2 are signaled independently with (Extended) ASSOCIATION Object inserted in the Path message, in which the Association Type indicating double - sided provisioning. In this case, the two unidirectional LSPs are - bound together to form an associated bidirectional LSP based on - identical (Extended) ASSOCIATION Objects in the two LSPs' Path - messages. + sided provisioning is included. In this case, the two unidirectional + LSPs are bound together to form an associated bidirectional LSP based + on identical (Extended) ASSOCIATION Objects in the two LSPs' Path + messages. The LSPs to be selected for the association are + provisioned by the management action applied at both endpoints. 3.3. Asymmetric Bandwidth Signaling Overview This section provides an overview of the methods for signaling asymmetric upstream and downstream bandwidths for the associated bidirectional LSPs. 3.3.1. Single Sided Provisioning A new REVERSE_LSP Object for use in the single sided provisioning model is defined in this document, in Section 4.4. When the single sided provisioning model is used, a SENDER_TSPEC object can be added in the REVERSE_LSP Object as a subobject in the initiating LSP's Path message to specify a different bandwidth for the reverse LSP. As - described in this document, addition of the REVERSE_LSP Object also - allows the initiating node to control the reverse LSP by including - other existing objects in a REVERSE_LSP Object. + described in Section 4.4, addition of the REVERSE_LSP Object also + allows the initiating node to control other aspects of the reverse + LSP (such as its path) by including other existing objects in a + REVERSE_LSP Object. Consider again the topology described in Figure 1, where the creation of reverse LSP2 is triggered by LSP1. Node A signals LSP1 with the (Extended) ASSOCIATION Object with Association Type indicating single sided provisioning and inserts a SENDER_TSPEC subobject for use by LSP2 in the REVERSE_LSP Object in the Path message. Node B then establishes the LSP2 in the reverse direction using the asymmetric bandwidth thus specified by LSP1 and allows node A to control the reverse LSP2. @@ -306,21 +317,22 @@ 3.4. Recovery LSP Overview Recovery of each unidirectional LSP forming the bidirectional LSP is independent [RFC5654] and is based on the parameters signaled in their respective RSVP Path messages. Recovery LSP association is based on the identical content of the (Extended) ASSOCIATION Objects signaled in their Path messages during the initial LSP setup for both single sided and double sided - provisioning. + provisioning. As defined, see [RFC6780], multiple ASSOCIATION + objects may be present in the signaling of a single LSP. 4. Message and Object Definitions 4.1. RSVP Message Formats This section presents the RSVP message-related formats as modified by this document. Unmodified RSVP message formats are not listed. The format of a Path message is as follows: @@ -350,22 +361,21 @@ The ASSOCIATION Object is populated using the rules defined below for associating two reverse unidirectional LSPs to form an associated bidirectional LSP. Association Types: In order to bind two reverse unidirectional LSPs to be an associated bidirectional LSP, the Association Type MUST be set to indicate either single sided or double sided LSPs. - The new Association Types are defined as follows (values are - temporary early allocations as per RFC7120): + The new Association Types are defined as follows: Value Type ----- ----- 3 Double Sided Associated Bidirectional LSP (D) 4 Single Sided Associated Bidirectional LSP (A) Association ID: For both single sided and double sided provisioning, Association @@ -403,22 +413,21 @@ node that originates the association for the bidirectional LSP. 4.4. REVERSE_LSP Object Definition 4.4.1. REVERSE_LSP Object Format The information of the reverse LSP is specified via the REVERSE_LSP Object. This is an optional object carried in a Path message with Class Number in the form 11bbbbbb and has the following format: - Class_Num = 203 (of the form 11bbbbbb), C_Type = 1 (values are - temporary early allocations as per RFC7120) + Class_Num = 203, C_Type = 1. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | // (Subobjects) // | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 4.4.2. REVERSE_LSP Subobjects @@ -498,21 +507,27 @@ Egress nodes which support the Association Types defined in this document identify the unidirectional LSPs of an associated bidirectional LSP based on (Extended) ASSOCIATION Objects carried in Path messages. Note that an ingress node will normally be the ingress for one of the unidirectional LSPs that make up an associated bidirectional LSP. When an egress node receives a Path message containing an (Extended) ASSOCIATION Object with one of the Association Types defined in this document, it MUST attempt to identify other LSPs (including ones for which it is an ingress node) with which the LSP being processed is associated. As defined above, - such associations are made per the rules defined in [RFC6780]. + such associations are made per the rules defined in [RFC6780]. If + the egress node does not support the Association Types defined in + this document, it MUST return a PathErr with Error Code "Admission + Control Failure (01) [RFC2205]" and Sub-code "Bad Association Type + (5) [RFC4872]". An LSP not being associated at the time of signaling + (for example, during rerouting or re-optimization) on an egress node + is not necessarily considered an error condition. Associated bidirectional LSP teardown follows the standard procedures defined in [RFC3209] and [RFC3473] either without or with the administrative status. Generally, the teardown procedures of the unidirectional LSPs forming an associated bidirectional LSP are independent of each other, so it is possible that while one LSP follows graceful teardown with administrative status, the reverse LSP is torn down without administrative status (using PathTear/ResvTear/PathErr with state removal). See Section 5.3 below for additional rules related to LSPs established using single sided @@ -552,67 +567,69 @@ Extended ASSOCIATION Object with the Association Type set to "Single Sided Associated Bidirectional LSP" MUST include a REVERSE_LSP Object in the Path message of the LSP when it wishes to control the reverse LSP originating on the other endpoint node. The REVERSE_LSP subobject MAY contain any of the specified objects which the initiating node desires to have included in the Path message for the associated reverse LSP. A REVERSE_LSP Object MUST contain at least one subobject. If there is no subobject to be added in the REVERSE_LSP Object, then the REVERSE_LSP Object MUST NOT be - added in the Path message. + added in the Path message. The REVERSE_LSP Object MUST NOT be + included in a REVERSE_LSP Object. A node receiving a valid Path message containing a REVERSE_LSP Object that is not the egress node for the LSP being signaled MUST forward the REVERSE_LSP Object unchanged in the outgoing Path message. An egress node, upon receiving a Path message containing an REVERSE_LSP Object MUST verify that the Path message contains an ASSOCIATION or Extended ASSOCIATION object with the Association Type set to "Single Sided Associated Bidirectional LSP". If it does not, the Path message MUST NOT trigger a reverse LSP. This verification failure SHOULD NOT trigger any RSVP message but can be logged locally, and perhaps reported through network management mechanisms. Once validated, the egress node MUST use the subobjects contained in any present REVERSE_LSP Objects in the management of the reverse LSP described in the previous section. Note that the contents of a REVERSE_LSP Object may change over the life of an LSP and such changes MUST result in corresponding changes in the reverse LSP. An - egress node MUST tear down and reestablish a new reverse LSP when - REVERSE_LSP Object is either added or removed in the received Path - message. + addition or removal of the REVERSE_LSP Object in the received Path + message may cause an egress node to teardown and reestablish a new + reverse LSP, or trigger re-optimization or in-place modification of + the LSP (which may depend on the local policy). 5.2.1. Compatibility For REVERSE_LSP Object The REVERSE_LSP Object is defined with class numbers in the form 11bbbbbb, which ensures compatibility with non-supporting nodes. Per [RFC2205], such nodes will ignore the object but forward it without modification. 5.3. Single Sided Associated Bidirectional LSP Setup and Teardown An egress node, upon receiving a Path message containing an ASSOCIATION or Extended ASSOCIATION Object with Association Type set to "Single Sided Associated Bidirectional LSP" MUST create an LSP in - the reverse direction or reject the Path message by sending a - PathErr. + the reverse direction or reject the Path message. If the creation of + a reverse LSP fails, the egress node MUST return a PathErr with Error + code "Admission Control Failure (01) [RFC2205]" and Sub-code "Reverse + LSP Failure" defined in this document. If REVERSE_LSP Object is not present in the received Path message of the LSP, the egress node SHOULD use the LSP properties from the received LSP Path message to signal the LSP in the reverse direction - (which may depend on the local policy). Note that the contents of - the received Path message may change over the life of an LSP and such - changes MUST result in corresponding changes in the reverse LSP. The - teardown of the initiating LSP SHOULD trigger the teardown of the - reverse LSP, however, teardown of the reverse LSP SHOULD NOT trigger - the teardown of the initiating LSP (which may depend on the local + (which may depend on the local policy). The teardown of the + initiating LSP SHOULD trigger the teardown of the reverse associated + LSP, however, teardown of the reverse LSP SHOULD NOT trigger the + teardown of the initiating LSP (which may depend on the local policy). If REVERSE_LSP Object is present in the received Path message of the LSP, the egress node follows the procedure defined in Section 5.2 to setup the reverse LSP. If initiating node controlling the reverse LSP, wishes to tear down the associated bidirectional LSP, the initiating node sends a PathTear message to the egress node, the egress node MUST trigger to tear down the reverse associated LSP, however, teardown of the reverse LSP SHOULD NOT trigger the teardown of the initiating LSP (which may depend on the local policy). @@ -647,25 +664,39 @@ Class Names, Class Numbers, and Class Types subregistry is included in this registry. This registry will be extended for new Class Number (Class-Num) and Class Type (C-type) for RSVP REVERSE_LSP Object requested in the 11bbbbbb range defined in this document as follows: Class Number Class Name Reference 203 REVERSE_LSP Section 4.4 - - REVERSE_LSP : Class Type or C-type = 1 + o REVERSE_LSP : Class Type or C-type = 1 Specified REVERSE_LSP Class Number and Class Type values are temporary early allocations as per RFC7120. +6.3. Reverse LSP Failure PathErr Sub-code + + IANA maintains the "RSVP Parameters" registry (see + http://www.iana.org/assignments/rsvp-parameters/rsvp-parameters.xml). + Error Codes and Globally-Defined Error Value Sub-Codes subregistry is + included in this registry. + + This registry will be extended for the new PathErr Sub-code defined + in this document as follows: + + Error Code = 01: "Admission Control Failure" (see [RFC2205]) + + o "Admission Control Failure/Reverse LSP Failure" (TBA) + There are no other IANA considerations introduced by this document. 7. Security Considerations This document introduces two new Association Types, however, no new security issues relating to the (Extended) ASSOCIATION Object are introduced. The procedures defined in this document result in an increased state information carried in signaling messages. The presence of the @@ -689,23 +720,35 @@ provisioning model and Lou Berger, Daniel King and Deborah Brungard for the review of the document. At the same time, the authors would also like to acknowledge the contributions of Bo Wu, Xihua Fu, Lizhong Jin for the initial discussions, and Wenjuan He for the prototype implementation. The authors would also like to thank Siva Sivabalan, Eric Osborne and Robert Sawaya for the discussions on the ASSOCIATION Object. The authors would like to thank Matt Hartley for providing useful suggestions on the document and Lou Berger for careful editorial reviews. -9. References +9. Contributing Authors -9.1. Normative References + Fan Yang + ZTE + + Email: yang.fan240347@gmail.com + + Weilian Jiang + ZTE + + Email: jiang.weilian@gmail.com + +10. References + +10.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2205] Braden, B., Zhang, L., Berson, S., Herzog, S., and S. Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1 Functional Specification", RFC 2205, September 1997. [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP @@ -719,21 +762,25 @@ Extensions in Support of End-to-End Generalized Multi- Protocol Label Switching (GMPLS) Recovery", RFC 4872, May 2007. [RFC4873] Berger, L., Bryskin, I., Papadimitriou, D., and A. Farrel, "GMPLS Segment Recovery", RFC 4873, May 2007. [RFC6780] Berger, L., Le Faucheur, F., and A. Narayanan, "RSVP Association Object Extensions", RFC 6780, October 2012. -9.2. Informative References + [RFC5511] Farrel, A., "Routing Backus-Naur Form (RBNF) - A Syntax + Used to Form Encoding Rules in Various Routing Protocol + Specifications", RFC 5511, April 2009. + +10.2. Informative References [RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation Element (PCE)-Based Architecture", RFC 4655, August 2006. [RFC5420] Farrel, A., Ed., Papadimitriou, D., Vasseur, JP., and A. Ayyangarps, "Encoding of Attributes for MPLS LSP Establishment Using Resource Reservation Protocol Traffic Engineering (RSVP-TE)", RFC 5420, February 2009. [RFC5654] Niven-Jenkins, B., Brungard, D., Betts, M., Sprecher, N., @@ -766,20 +813,10 @@ Ruiquan Jing China Telecom Email: jingrq@ctbri.com.cn Rakesh Gandhi (editor) Cisco Systems Email: rgandhi@cisco.com - - Fan Yang - ZTE - - Email: yang.fan240347@gmail.com - - Weilian Jiang - ZTE - - Email: jiang.weilian@gmail.com