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 30, 2012 October 31, 2011 RSVP-TE Extensions for Configuration SRLG of an FA draft-zhang-ccamp-srlg-fa-configuration-04.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 January 8, 2012. Abstract 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. Zhang Expires 2012 [Page 1] draft-zhang-ccamp-srlg-fa-configuration-04.txt October 2011 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 RFC-2119 [RFC2119]. Table of Contents 1. Introduction ................................................ 2 2. RSVP-TE Requirements......................................... 4 2.1. SRLG Collection Indication ............................. 4 2.2. SRLG Collection......................................... 4 2.3. SRLG Update ............................................ 4 3. RSVP-TE Extensions .......................................... 4 3.1. SRLG Collection Flag ................................... 4 3.2. SRLG sub-object ........................................ 5 4. Signaling Procedures ........................................ 6 4.1. SRLG Collection ........................................ 6 4.2. SRLG Update ............................................ 6 5. Manageability Considerations ................................ 7 5.1. Policy Configuration ................................... 7 5.2. Coherent SRLG IDs ...................................... 7 6. IANA Considerations ......................................... 7 6.1. RSVP Attribute Bit Flags ............................... 7 6.2. ROUTE_RECORD Object .................................... 8 7. Security Considerations ..................................... 8 8. References .................................................. 8 9. Authors' Addresses .......................................... 10 1. Introduction As described in [RFC4206], H-LSP (Hierarchical LSP) can be used for carrying one or more other LSPs. [RFC6107] 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 [RFC6107], in the data plane the LSPs are stitched so that there is no label stacking or nesting. Zhang Expires 2012 [Page 2] draft-zhang-ccamp-srlg-fa-configuration-04.txt October 2011 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 [RFC6107], 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 manual 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 [RFC6107]. Zhang Expires 2012 [Page 3] draft-zhang-ccamp-srlg-fa-configuration-04.txt October 2011 In addition, Section 1.2 of [RFC6107] 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-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 Collection 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 should be capable of updating the newly SRLG information to the endpoints. 3. RSVP-TE Extensions 3.1. SRLG Collection Flag In order to indicate nodes that SRLG collection is desired, this document defines a new flag in the Attribute Flags TLV, which is carried in an LSP_REQUIRED_ATTRIBUTES Object: o Bit Number (to be assigned by IANA, recommended bit zero): SRLG Collection flag The SRLG Collection flag is meaningful on a Path message. If the SRLG Collection flag is set to 1, it means that the SRLG information Zhang Expires 2012 [Page 4] draft-zhang-ccamp-srlg-fa-configuration-04.txt October 2011 should be reported to the head and tail node along the setup of the LSP. The rules of the processing of the Attribute Flags TLV are not changed. 3.2. SRLG sub-object This document defines a new RRO sub-object (ROUTE_RECORD sub-object) to record the SRLG information of the LSP. Its format is modeled on the RRO sub-objects defined in [RFC3209]. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SRLG ID 1 (4 bytes) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ ...... ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SRLG ID n (4 bytes) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type The type of the sub-object, to be assigned by IANA, which is recommended 34. Length The Length contains the total length of the sub-object in bytes, including the Type and Length fields. The Length depends on the number of SRLG IDs. SRLG Id The 32-bit identifier of the SRLG. Reserved This field is reserved. It SHOULD be set to zero on transmission and MUST be ignored on receipt. The rules of the processing of the LSP_REQUIRED_ATTRIBUTES Object and ROUTE_RECORD Object are not changed. Zhang Expires 2012 [Page 5] draft-zhang-ccamp-srlg-fa-configuration-04.txt October 2011 4. Signaling Procedures 4.1. SRLG Collection Typically, the head node gets the route information of an LSP by adding a RRO which contains the sender's IP addresses in the Path message. If a head node also desires SRLG recording, it sets the SRLG Collection Flag in the Attribute Flags TLV which can be carried in an LSP_REQUIRED_ATTRIBUTES Object. When a node receives a Path message which carries an LSP_REQUIRED_ATTRIBUTES Object and the SRLG Collection Flag is set, if local policy determines that the SRLG information should not be provided to the endpoints, it must return a PathErr message to reject the Path message. Otherwise, it must add an SRLG sub-object to the RRO to carry the local SRLG information. Then it forwards the Path message to the next node in the downstream direction. Following the steps described above, the intermediate nodes of the LSP can collect the SRLG information in the RRO during the forwarding of the Path message hop by hop. When the Path message arrives at the tail node, the tail node can get the SRLG information from the RRO. Before the Resv message is sent to the upstream node, the tail node adds an SRLG sub-object to the RRO. The collected SRLG information can be carried in the SRLG sub-object. Therefore, during the forwarding of the Resv message in the upstream direction, the SRLG information is not needed to be collected hop by hop. Based on the above procedure, the endpoints can get the SRLG information automatically. Then the endpoints can for instance advertise it as a TE link to the routing instance based on the procedure described in [RFC6107] and configure the SRLG information of the FA automatically. It is noted that a node (e.g. the edge node of a domain) may edit the RRO to remove the route information (e.g. node, interface identifier information) before forwarding it due to some reasons (e.g. confidentiality or reduce the size of RRO), but the SRLG information should be retained if it is desirable for the endpoints of the LSP. 4.2. SRLG Update When the SRLG information of a link is changed, the LSPs using that link should be aware of the changes. The procedures defined in Zhang Expires 2012 [Page 6] draft-zhang-ccamp-srlg-fa-configuration-04.txt October 2011 Section 4.4.3 of [RFC 3209] MUST be used to refresh the SRLG information. 5. Manageability Considerations 5.1. Policy Configuration In a border node of inter-domain or inter-layer network, the following SRLG processing policy should be capable of being configured: o Whether the SRLG IDs of the domain or specific layer network can be exposed to the nodes outside the domain or layer network. o If the SRLG IDs must not be exposed to the nodes outside of the domain or specific layer network by policy, the border node must reject the Path message desiring SRLG recording and send a PathErr message with the defined error code ''Policy Control Failure''/''Inter- domain policy failure''. 5.2. Coherent SRLG IDs In a multi-layer multi-domain scenario, SRLG ids may be configured by different management entities in each layer/domain. In such scenarios, maintaining a coherent set of SRLG IDs is a key requirement in order to be able to use the SRLG information properly. Thus, SRLG IDs must be unique. Note that current procedure is targeted towards a scenario where the different layers and domains belong to the same operator, or to several coordinated administrative groups. Further scenarios, where coherence in the SRLG IDs cannot be guaranteed are out of the scope of the present document and are left for further study. 6. IANA Considerations 6.1. RSVP Attribute Bit Flags The IANA has created a registry and manages the space of attributes bit flags of Attribute Flags TLV as described in section 11.3 of [RFC5420]. It is requested that the IANA makes assignments from the Attribute Bit Flags. This document introduces a new Attribute Bit Flag: - Bit number: TBD (0) Zhang Expires 2012 [Page 7] draft-zhang-ccamp-srlg-fa-configuration-04.txt October 2011 - Defining RFC: this I-D - Name of bit: SRLG Collection Flag - The meaning of the Attribute Flags TLV on a Path is defined in this I-D 6.2. ROUTE_RECORD Object IANA has made the following assignments in the "Class Names, Class Numbers, and Class Types" section of the "RSVP PARAMETERS" registry located at http://www.iana.org/assignments/rsvp-parameters. We request that IANA make assignments from the ROUTE_RECORD [RFC3209] portions of this registry. This document introduces a new RRO sub-object: Type Name Reference --------- ---------------------- --------- TBD (34) SRLG sub-object This I-D 7. Security Considerations TBD. 8. Acknowledgements The authors would like to thank Igor Bryskin and Ramon Casellas for their useful comments to the document. 9. References [RFC2119] S. Bradner, "Key words for use in RFCs to indicate requirements levels", RFC 2119, March 1997. [RFC3209] D. Awduche, L. Berger, D. Gan, T. Li, V. Srinivasan and G. Swallow, " RSVP-TE: Extensions to RSVP for LSP Tunnels", RFC 3209, December 2001. Zhang Expires 2012 [Page 8] draft-zhang-ccamp-srlg-fa-configuration-04.txt October 2011 [RFC3477] K. Kompella, Y. Rekhter, "Signalling Unnumbered Links in Resource ReSerVation Protocol - Traffic Engineering (RSVP- TE)", rfc3477, January 2003. [RFC4206] K. Kompella, Y. Rekhter, "Label Switched Paths (LSP) Hierarchy with Generalized Multi-Protocol Label Switching (GMPLS) Traffic Engineering (TE)", RFC 4206, October 2005. [RFC4208] G. Swallow, J. Drake, Boeing, H. Ishimatsu, and Y. Rekhter, "Generalized Multiprotocol Label Switching (GMPLS) User-Network Interface (UNI): Resource ReserVation Protocol-Traffic Engineering (RSVP-TE) Support for the Overlay Model", RFC 4208, October 2005. [RFC4874] CY. Lee, A. Farrel, S. De Cnodder, " Exclude Routes - Extension to Resource ReserVation Protocol-Traffic Engineering (RSVP-TE) ", RFC 4874, April 2007. [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. [RFC5420] A. Farrel, D. Papadimitriou, J.P, and A. Ayyangar, "Encoding of Attributes for MPLS LSP Establishment Using Resource Reservation Protocol Traffic Engineering (RSVP- TE)", RFC 5420, February 2009. [RFC6107] K. Shiomoto, A. Farrel, " Procedures for Dynamically Signaled Hierarchical Label Switched Paths ", RFC 6107, February 2011. Zhang Expires 2012 [Page 9] draft-zhang-ccamp-srlg-fa-configuration-04.txt October 2011 10. Authors' Addresses 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 Xiaobing Zi Huawei Technologies F3-5-B R&D Center, Huawei Base Bantian, Longgang District Shenzhen 518129 P.R.China Zhang Expires 2012 [Page 10] draft-zhang-ccamp-srlg-fa-configuration-04.txt October 2011 Phone: +86-755-28973229 Email: zixiaobing@huawei.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 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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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. Zhang Expires 2012 [Page 12]