MPLS Working Group Sandeep Bishnoi Internet Draft Pranjal Kumar Dutta Intended status: Standards Track Alcatel-Lucent Expires: April 2010 October 19, 2009 LDP Node and FEC group draft-bishnoi-mpls-ldp-node-group-00.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." 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Abstract [RFC5036] and [MLDP] describes the Label Distribution Protocol (LDP) for setup of point-to-point (P2P), point to multi-point (P2MP) and multipoint-to-multipoint (MP2MP) Label Switched Paths (LSPs). Upstream node selection for P2MP/MP2MP LSP and label map propagation for P2P is based on route availability and local policy. If multiple paths are available then there is no method for selection of certain preferred nodes. A new method is defined in this document that can optionally be used as a tiebreaker among multiple available paths in upstream node selection. This method provides a mechanism to guide traffic via specific set of nodes in a network. Table of Contents 1. Introduction...................................................2 2. Terminology....................................................3 3. Conventions used in this document..............................3 4. Structure for LDP Node group mapping and FEC group advertisement3 4.1. Node group advertisement..................................3 4.2. FEC group mapping.........................................4 5. Limitations....................................................5 6. Security Considerations........................................5 7. IANA Considerations............................................5 8. References.....................................................5 8.1. Normative References......................................5 9. Acknowledgments................................................6 1. Introduction LDP downstream node selection for P2P LSP and upstream node selection for P2MP/MP2MP LSP is based on route availability at each node. If multiple such paths are available then node resolving LDP FEC based on route is based on local policy. In case of availability of multiple paths, there is no mechanism to direct traffic towards preferred nodes or restrict traffic to flow via nodes that are not preferred. Few applications that use LDP LSP also require redundant paths for minimum downtime of service. One of the requirements for such applications is to establish LSP via disjoint nodes. Bishnoi, et. al Expires April 19, 2010 [Page 2] Internet-Draft LDP Node and FEC Group October 2009 This proposal defines a method to identify and select a preferred node group to setup LSP. Scheme defined in this document also allows restricting traffic flow within a certain set of nodes and also avoiding nodes that belong to a group that is not preferred. This proposal is only for preferred node selection and does not address selection or avoiding preferred links. This document defines a node level attribute to identify selection group and a mechanism to advertise and propagate an LDP FEC with group attribute. This scheme may be applied to P2P and P2MP/MP2MP LSP. This method can be applied to P2P LSP during decision process to send label map to a peer. For P2MP/MP2MP LSP, this method is applied during upstream node selection. This document defines two new LDP parameters: . Node group . FEC group mapping 2. Terminology This document uses the terminology defined in [RFC5036] and [MLDP]. 3. 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]. 4. LDP node and FEC group Group mapping of a node may be advertised to a peer using "Node Group Capability" message. Group mapping per FEC may be advertised to a peer using "FEC Group TLV" in Label Map message. 4.1. Node Group Capability An LSR may advertise node group map capability to an LDP peer using method defined in [RFC5561]. Node group message must be silently discarded if the receiving node does not support it. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |1|0| Node Group Capability | Length | Bishnoi, et. al Expires April 19, 2010 [Page 3] Internet-Draft LDP Node and FEC Group October 2009 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-| | Node Group Map | |-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type: Node Group Capability (TBD) Node Group Map: A 32-bit node group map. 4.2. FEC Group TLV FEC group mapping TLV may be included in Label Map message to advertise node group to be used for upstream node selection. FEC group mapping must be silently discarded if the receiving node does not support it. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |1|0| FEC Group Mapping | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-| | Include Group | |-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Exclude Group | |-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |I|E| Reserved | |-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type: FEC Group Mapping (TBD) Include Group: 32-bit map of node groups to include while propagating label map Exclude Group: 32-bit map of node groups to exclude while propagating label map Include Type (I): Strict (1) or Loose (0) Exclude Type (E): Strict (1) or Loose (0) A node processing P2P LSP label map message propagates it further to upstream node based on criteria defined in [RFC5036]. A node Bishnoi, et. al Expires April 19, 2010 [Page 4] Internet-Draft LDP Node and FEC Group October 2009 processing P2MP/MP2MP LSP label map message selects a single upstream node based on criteria defined in [MLDP]. If a FEC group mapping is included in label map message then the receiving node may choose sending the label map message further to its peers based on group mapping received in label map. FEC group mapping must then match peer node group advertisement to qualify to receive a label map. For P2P LSP, if include type is "Strict" then the label map message MUST only be propagated to peers that have all the groups. If exclude type is "Strict" then the label map message MUST not be propagated to peers that have any of the groups. For P2MP/MP2MP LSP, if include type is "Strict" then the label map message MUST only be propagated to a peer that has all the groups. If exclude type is "Strict" then the label map message MUST not be propagated to a peer that has any of the groups. If multiple peers qualify then include and exclude type must be used as a tiebreaker. "Strict" is preferred over "Loose" group map. 5. Limitations This scheme does not guarantee setup of LSP if "Strict" group option for an LDP FEC is enabled. This scheme requires proper network provisioning for it to work. 6. Security Considerations The same security considerations apply as for the base LDP specification, as described in [RFC5036] and MP LDP specification, as described in [MLDP]. 7. IANA Considerations This document requires allocation of Node Group Capability and FEC Group TLV. 8. References 8.1. Normative References [MLDP] I. Minei, K., Kompella, I. Wijnands, B. Thomas, "Label Distribution Protocol Extensions for Point-to-Multipoint Bishnoi, et. al Expires April 19, 2010 [Page 5] Internet-Draft LDP Node and FEC Group October 2009 and Multipoint-to-Multipoint Label Switched Paths", draft-ietf-mpls-ldp-p2mp-06.txt, May 2008 [RFC5036] Andersson, L., Minei, I., and B. Thomas, "LDP Specification", RFC 5036, October 2007. [RFC5561] B. Thomas, K. Raza, S. Aggarwal, R. Aggarwal, JL. Le Roux, "LDP Capabilities", RFC 5561, July 2009. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. 9. Acknowledgments The authors would like to acknowledge the comments and suggestions from Wim Henderickx. This document was prepared using 2-Word-v2.0.template.dot. Authors' Addresses Sandeep Bishnoi Alcatel-Lucent 701 E Middlefield Road, Mountain View, CA 94043 USA Email: sandeep.bishnoi@alcatel-lucent.com Pranjal Kumar Dutta Alcatel-Lucent 701 E Middlefield Road, Mountain View, CA 94043 USA Email: pdutta@alcatel-lucent.com Bishnoi, et. al Expires April 19, 2010 [Page 6]