Network Working Group Fatai Zhang Internet-Draft Dan Li Intended status: Standards Track Huawei O. Gonzalez de Dios Telefonica Investigacion y Desarrollo C. Margaria. C Nokia Siemens Networks Expires: April 20, 2011 October 20, 2010 RSVP-TE Extensions for Configuration SRLG of an FA draft-zhang-ccamp-srlg-fa-configuration-01.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 April 20, 2011. Abstract Zhang Expires April 2011 [Page 1] draft-zhang-ccamp-srlg-fa-configuration-01.txt October 2010 This memo provides extensions for the Resource ReserVation Protocol- Traffic Engineering (RSVP-TE) for the support of the automatic discovery of SRLG of an LSP. Table of Contents 1. Introduction.................................................2 2. RSVP-TE Requirements.........................................4 2.1. SRLG Collection Indication..............................4 2.2. SRLG Collecting.........................................4 2.3. SRLG Update.............................................4 3. RSVP-TE Extensions...........................................4 3.1. SRLG Collection Indication..............................4 3.2. SRLG Information Object.................................4 3.3. Signaling Procedures....................................5 4. Manageability Considerations.................................5 5. IANA Considerations..........................................6 6. Security Considerations......................................6 7. References...................................................6 1. Introduction As described in [RFC4206], H-LSP (Hierarchical LSP) can be used for carrying one or more other LSPs. [LSP-Hierarchy-bis] further mentions the implementation of H-LSP. In packet networks, e.g. MPLS networks, H-LSP mechanism can be implemented by MPLS label stack. In non-packet networks where the label is implicit, label stacks are not possible, and H-LSPs rely on the ability to nest switching technologies. Thus, for example, a lambda switch capable (LSC) LSP can carry a time division multiplexing (TDM) LSP, but cannot carry another LSC LSP. S-LSP (LSP Stitching), which is defined in [RFC5150], is an LSP that represents a segment of another LSP, i.e., the S-LSP is viewed as one hop by another LSP. As described in [LSP-Hierarchy-bis], in the data plane the LSPs are stitched so that there is no label stacking or nesting. Thus, an S-LSP must be of the same switching technology as the end-to-end LSP that it facilitates. Therefore, H-LSP mechanism can be used in both multi-domain and multi-layer scenarios and S-LSP mechanism can only be used in multi- domain scenario. Both of the H-LSP and S-LSP can be advertised as a TE link in a GMPLS routing instance for path computation purpose. As described in [LSP- zhang Expires April 2011 [Page 2] draft-zhang-ccamp-srlg-fa-configuration-01.txt October 2010 Hierarchy-bis], if the LSP (H-LSP or S-LSP) is advertised in the same instance of the control plane that advertises the TE links from which the LSP is constructed, the LSP is called an FA. In multi-domain or multi-layer context, the path information of an LSP may not be provided to the ingress node for confidential reasons and the ingress node may not run the same routing instance with the intermediate nodes traversed by the path. In such scenarios, the ingress node can not get the SRLG information of the path information which the LSP traverse. Even if the ingress node has the same routing instance with the intermediate nodes traversed by the path, the path information of the H-LSP or S-LSP may not be provided to the ingress node. Hence the ingress node may also not know the SRLG of the path the LSP traverses. In the case that the ingress node does not get the SRLG of the path the LSP traverses(i.e. H-LSP or S-LSP), there are disadvantages as follows: o SRLG-disjoint path, for instance in case of end-to-end path protection, cannot be calculated o Intermediate nodes of a pre-planned shared restoration LSP cannot correctly decide on the SRLG-disjointness between two PPRO (PRIMARY_PATH_ROUTE Object) o In case that an LSP is advertised as a TE-Link, the ingress node cannot provide the correct SRLG for the TE-Link automatically In case that an LSP is advertised as a TE-Link, the SRLG information of the TE link needs to be configured manually or automatically. However, for manually configuration, there are some disadvantages (e.g., require configuration coordination and additional management; manual errors may be introduced) mentioned in Section 1.3.4 of [LSP- Hierarchy-bis]. In addition, Section 1.2 of [LSP-Hierarchy-bis] describes it is desirable to have a kind of automatic mechanism to advertise the FA (i.e., to signal an LSP and automatically coordinate its use and advertisement in any of the ways with minimum involvement from an operator). Thus, in order to provide the SRLG information to the TE link automatically when an LSP (H-LSP or S-LSP) is advertised as a TE link, allow disjoint path calculation at ingress and allow correct pre- zhang Expires April 2011 [Page 3] draft-zhang-ccamp-srlg-fa-configuration-01.txt October 2010 planned shared LSP to correctly share resource, this document provides an automatic mechanism to collect the SRLG used by a LSP automatically. 2. RSVP-TE Requirements 2.1. SRLG Collection Indication The head nodes of the LSP must be capable of indicating whether the SRLG information of the LSP should be collected during the signaling procedure of setting up an LSP. 2.2. SRLG Collecting The SRLG information can be collected during the setup of an LSP. Then the endpoints of the LSP can get the SRLG information and use it for routing, sharing and TE link configuration purposes. 2.3. SRLG Update When the SRLG information changes, the endpoints of the LSP need to be capable of updating the SRLG information of the path. It means that the signaling needs to be capable of updating the newly SRLG information to the endpoints. 3. RSVP-TE Extensions 3.1. SRLG Collection Indication In order to indicate nodes that SRLG collection is desired, a new flag in the SESSION_ATTRIBUTE is needed: 0x08 SRLG recording desired This flag indicate that SRLG information should be recorded along the LSP. 3.2. SRLG Information Object An SRLG information object is defined to carry the SRLG information of the LSP. The Class-Num and the C-Type of the SRLG Information Object need to be assigned by the IANA. zhang Expires April 2011 [Page 4] draft-zhang-ccamp-srlg-fa-configuration-01.txt October 2010 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 | Class-Num | C-Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SRLG ID (4 bytes) | // ...... // | SRLG ID (4 bytes) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The SRLG ID list carries the SRLG information of the LSP. This object can be carried in a Path/Resv message. The SRLG ID can be added to the SRLG Information Object in a Path/Resv message hop by hop. Then the endpoints of the LSP can get the SRLG information of the path. 3.3. Signaling Procedures When an LSP head node determines that it needs to get the SRLG information of the LSP, it sets the ''SRLG recording desired'' in the SESSION_ATTRIBUTE when it sends the Path message to the downstream node. The downstream nodes record the SRLG information in the SRLG Information Object hop by hop. Then the tail node of the LSP can get the SRLG information from the SRLG Information Object. When the tail node of the LSP receives the Path message and the ''SRLG recording desired'' is set in the SESSION_ATTRIBUTE object, it can get the SRLG information from the SRLG Information Object of the Path message. Hence it can add the collected SRLG information into the SRLG Information Object of a Resv message which will be forwarded hop by hop in the upstream direction until it arrives the head node. Then the head node can also get the SRLG information of the LSP from the SRLG Information Object in the Resv message. Based on the above procedure, the endpoints can get the SRLG information automatically. Then the endpoints can for instance configure the SRLG information and advertise it as a TE link to the routing instance based on the procedure described in [LSP-Hierarchy- bis]. 4. Manageability Considerations TBD. zhang Expires April 2011 [Page 5] draft-zhang-ccamp-srlg-fa-configuration-01.txt October 2010 5. IANA Considerations TBD. 6. Security Considerations TBD. 7. References [LSP-Hierarchy-bis] K. Shiomoto, A. Farrel, " Procedures for Dynamically Signaled Hierarchical Label Switched Paths ", draft-ietf-ccamp-lsp-hierarchy-bis-08, August 2010. [RFC 4206] K. Kompella, Y. Rekhter, " Label Switched Paths (LSP) Hierarchy with Generalized Multi-Protocol Label Switching (GMPLS) Traffic Engineering (TE) ", rfc4206, October 2005. [RFC 4874] CY. Lee, A. Farrel, S. De Cnodder, " Exclude Routes - Extension to Resource ReserVation Protocol-Traffic Engineering (RSVP-TE) ", rfc4874, April 2007. [RFC 3477] K. Kompella, Y. Rekhter, " Signalling Unnumbered Links in Resource ReSerVation Protocol - Traffic Engineering (RSVP- TE) ", rfc3477, January 2003. [RFC5150] Ayyangar, A., Vasseur, J.P, and Farrel, A., "Label Switched Path Stitching with Generalized Multiprotocol Label Switching Traffic Engineering (GMPLS TE)", RFC 5150, February 2008. Authors' Addresses zhang Expires April 2011 [Page 6] draft-zhang-ccamp-srlg-fa-configuration-01.txt October 2010 Fatai Zhang Huawei Technologies F3-5-B R&D Center, Huawei Base Bantian, Longgang District Shenzhen 518129 P.R.China Phone: +86-755-28972912 Email: zhangfatai@huawei.com Dan Li Huawei Technologies F3-5-B R&D Center, Huawei Base Bantian, Longgang District Shenzhen 518129 P.R.China Phone: +86-755-28970230 Email: danli@huawei.com Oscar Gonzalez de Dios Telefonica Investigacion y Desarrollo Emilio Vargas 6 Madrid, 28045 Spain Phone: +34 913374013 Email: ogondio@tid.es Cyril Margaria Nokia Siemens Networks St Martin Strasse 76 Munich, 81541 Germany Phone: +49 89 5159 16934 Email: cyril.margaria@nsn.com Intellectual Property The IETF Trust takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in any IETF Document or the extent to which any license zhang Expires April 2011 [Page 7] draft-zhang-ccamp-srlg-fa-configuration-01.txt October 2010 under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. 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