INTERNET DRAFT Expiration Date: November 2002 Ravi Sankar Mantha Nagabhushana Ramaswamy Chetan Kumar S Wipro Technologies May 2002 Resource Class considerations for CRLDP draft-mantha-resource-class-crldp-00.txt Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. 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/1id-abstracts.html The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html Abstract This draft extends the CRLDP signaling to include the resource class affinity vectors of an LSP in the label request message. We define resource class attributes for hierarchical LSPs and procedures to admit LSPs into links/tunnels based on the resource class constraints. Mantha et al. Expires Nov 2002 [Page 1] Internet Draft draft-mantha-resource-class-crldp-00.txt May 2002 1. Conventions Used in this Document CRLDP : Constraint-Based LDP CSPF : Constrained Shortest Path First LSP : Label Switched Path FA-LSP : Forwarding Adjacency - LSP TE : Traffic Engineering 2. Introduction The traffic engineering requirements for MPLS associates administrative grouping (coloring) for resources (links) and resource class affinity information to LSPs. These are the additional policy constraints that can be imposed on LSPs to restrict the links that this LSP can traverse. In other words, these constraints govern the admission of LSPs onto a Link. This affinity parameter of the LSP can be represented as an explicit inclusion and an explicit exclusion [MPLS-TE] vectors in LSP setup procedures. For explicit inclusion, resources that do not belong to any of these resource classes can not be considered to include in the LSP's path. For explicit exclusion, resources that belong to any of these resource classes are not considered for path selection. In addition, it may be a requirement for an LSP to pass through resources that belong to more than one administrative groups. For e.g. sometimes it may be required to constrain an LSP to take resources satisfying more than one constraints like bandwidth capability, geographical region it belongs to etc. This can be represented by an "include-all" vector [RSVP-TE]. Current CRLDP signaling [CRLDP] provides a mechanism to signal only the "Explicit inclusion (RsCls of Resource Class Tlv)" vector. Here we propose extensions to the existing CRLDP signaling mechanism to signal the other two resource class affinity vectors of an LSP while setting up a constrained path. MPLS architecture [MPLS-ARCH] allows setting up of hierarchical LSPs (tunnels), where the lower level LSPs are admitted into higher level LSPs. These tunnels are advertised either as FA-LSPs [LSP-HIER] or as TE-Links (with LSP Id as an attribute) [OSPF-LSPID] in MPLS Domain. TE properties advertised for FA-LSPs/ TE-Links include Resource Class Attributes. Currently there is no mechanism to associate resource class attributes to a tunnel. This necessitates deriving the administrative grouping for tunnels (tunnel coloring). In this draft, we propose method to derive the resource attributes for tunnels and procedures to admit LSPs into a tunnel based on the derived tunnel attributes and LSP's resource class affinity vectors Mantha et al. Expires Nov 2002 [Page 2] Internet Draft draft-mantha-resource-class-crldp-00.txt May 2002 3. Applicability The procedures defined in this draft enables one to consider tunnels as ERO objects in CR-LSP path computation with additional resource class constraint. With appropriate modifications to IGP TE extensions (refer Section 5.3), an automated path computation algorithm (like CSPF) can be provided with the resource class attributes of the tunnels. 4. Extensions to Label Request Message We propose a new Resource Class Tlv (see Also IANA considerations, section 6) in the Label Request Message of CR-LDP to include "Exclude-All" and "Include-All" vectors along with the existing "Include-Any" vector. 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| Type = TBO | Length = 12 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Include-Any | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Include-All | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Exclude-All | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type A fourteen-bit field carrying the value of the ResCls-TLV Type = To Be Obtained. Length Specifies the length of the value field in bytes = 12. Include-Any A 32-bit vector representing a set of administrative groups associated with an LSP, any of which renders a link acceptable. A vector with all bits set to zero (null vector) accepts any link. Include-All A 32-bit vector representing a set of administrative groups associated with an LSP, all of which must be present for a link to be acceptable. A vector with all bits set to zero (null vector) accepts any link. Mantha et al. Expires Nov 2002 [Page 3] Internet Draft draft-mantha-resource-class-crldp-00.txt May 2002 Exclude-All A 32-bit vector representing a set of administrative groups associated with an LSP, any of which renders a link unacceptable. A vector with all bits set to zero (null vector) accepts any link. 4.1 Processing of Resource Class Tlv The Exclude-All vector of the Resource Class Tlv MUST not have any common color with the Include-All and Include-Any vectors. Violation of the above makes the TLV malformed. The handling of such a malformed tlv is as described in [CRLDP]. The commonality of colors between the Include-All and the Include- Any vectors does not carry any meaningful information as the Include-All vector overrides the Include-Any vector. However, this draft does not preclude such a combination as it will not lead to any inconsistencies. 5. Resource Affinity Procedures The resource affinity procedures define the interpretation of resource class affinity vectors in the Resource Class Tlv in the context of admitting an LSP onto a Link/Tunnel. 5.1 Resource Attributes of a Link The resource attributes of a link can be represented by a single 32 bit mask. Link-attr A 32-bit vector representing the administrative groups a link is associated with. 5.2 Resource Attributes of Tunnels Unlike links, resource attributes of tunnels are represented by three vectors. Link-Include-Any-Attr A 32-bit vector represents a set of administrative groups, at least one of which, the links in the path taken by the tunnel MUST contain. Link-Include-All-Attr A 32-bit vector represents a set of administrative groups, all of which, the links in the path taken by the tunnel contains. Mantha et al. Expires Nov 2002 [Page 4] Internet Draft draft-mantha-resource-class-crldp-00.txt May 2002 Link-Exclude-All-Attr A 32-bit vector represents a set of administrative groups, any of which, the links in the path taken by the tunnels MUST not contain. 5.3 Tunnel Coloring The resource class attributes of a tunnel are derived from its resource class affinity vectors as follows. Initially assign null vectors to the resource class attribute vectors of a tunnel. a) Copy the Exclude-All vector to Link-Exclude-All-Attr. b) Copy the Include-All vector to Link-Include-All-Attr. c) If there is a single element in the Include-Any vector copy it to the Link-Include-All-Attr. Otherwise copy the Include-Any vector to Link-Include-Any-Attr. In order to use the tunnels in path computation procedures, the above mentioned attributes of a tunnel MAY be advertised by the IGP extensions to TE [OSPF-TE][ISIS-TE]. 5.4 Admission of LSPs into a Link In order to consider a link to include in an LSPs path, all the below mentioned conditions MUST satisfy. a) There should not be any common color (a bit in 32 bit vector) between the Link_attr of the link and the Exclude-Any vector of the LSP. (Link-attr & Exclude-All) == 0 b) A null set for the Include-Any vector of a LSP can take any link. Otherwise, the Link_attr of the link MUST contain at least one color from the Include-Any vector of the LSP. (Include-Any == 0) | ((Link-attr & Include-Any) != 0) c) A null set for the Include-All vector of a LSP can take any link. Otherwise, the Link_attr of the link MUST contain all colors from the Include-All vector of the LSP. (Include-All == 0) | ((Link-attr & Include-All) == Include-All) Mantha et al. Expires Nov 2002 [Page 5] Internet Draft draft-mantha-resource-class-crldp-00.txt May 2002 These are similar to that of RSVP-TE procedures [RSVP-TE]. Here it is given for the sake of completeness. 5.5 Admission of LSPs into a Tunnel Procedures to admit an LSP with resource class affinity vectors Include-Any, Exclude-All, Include-All into a tunnel with Link Attribute vectors, Link-Include-Any-Attr, Link-Include-All-Attr, Link-Exclude-Any-Attr are as follows: a) A null set for the Include-Any vector of a LSP can be admitted onto any tunnel. Otherwise either there should be at least one common color between the Include-Any vector and the Link-Include-All-Attr of the tunnel OR Include-Any vector should contain all (see NOTE) the colors present in Link-Include-Any-Attr of the tunnel. ((Include-Any == 0) | (Include-Any & Link-Include-All-Attr != 0) | (Include-Any & Link-Include-Any-Attr == Link-Include-Any-Attr)) b) A null set for the Include-All vector of a LSP can be admitted onto any tunnel. Otherwise, all colors in the Include-All vector should be present in the Link-Include-All-Attr of the tunnel. (Include-All & Link-Include-All-Attr) == Include-All c) A null set for the Exclude-All vector of a LSP can be admitted onto any tunnel. Otherwise, all colors in the Exclude-All vector should be present in the Link-Exclude-All-Attr of the tunnel. (Exclude-All & Link-Exclude-All-Attr) == Exclude-All To consider a LSP to admit into a tunnel all the above mentioned conditions MUST be satisfied. NOTE : Containing all colors is a MUST, suppose Include-Any vector is A, Link-Include-Any-Attr is B, B-A is not NULL. Then, it may happen that the tunnel would traverse at least one link that has Link-attr vector as subset of B-A). 6. IANA Considerations The TLV type value for the proposed resource class TLV is to be obtained from IANA. However, if the working group agrees to replace the existing resource class tlv of CR-LDP with the proposed Tlv then the same type value can be used. Mantha et al. Expires Nov 2002 [Page 6] Internet Draft draft-mantha-resource-class-crldp-00.txt May 2002 7. Security Considerations This document raises no new security issues for CR-LDP. The security mechanisms already proposed for CR-LDP continue to hold well. 8. Acknowledgments We thank all our colleagues and friends at WIPRO who have contributed and participated in discussions for this work. 9. References [CRLDP] Jamoussi, et. al., "Constraint-Based LSP Setup using LDP" RFC 3212, January 2002. [ISIS-TE] Smit, Li, IS-IS extensions for Traffic Engineering, draft -ietf-isis-traffic-04.txt, August 2001. [LSP-HIER] Kireeti Kompella, et. al., "LSP Hierarchy with Generalized MPLS TE", draft-ietf-mpls-lsp-hierarchy-05.txt, October 2002. [MPLS-ARCH] E. Rosen, et. al., "Multiprotocol Label Switching Architecture" RFC 3031, January 2001. [MPLS-TE] Awduche et. al., "Requirements for Traffic Engineering Over MPLS", RFC 2702, September 1999. [OSPF-LSPID] Chetan et. al., "Signalling LSPID's in OSPF TE", draft-chetan-lspid-ospf-00.txt, September 2002. [OSPF-TE] Katz, Yeung, Traffic Engineering Extensions to OSPF, draft-katz-yeung-ospf-traffic-06.txt, October 2001. [RSVP-TE] Awduche et al, "RSVP-TE: Extensions to RSVP for LSP Tunnels", RFC 3209, December 2001. 10. Author's Address Ravi Sankar Mantha Wipro Technologies K-312, 5th Block, Koramangala Bangalore-560095 India Phone : 91-80-5538301 Email : ravi.mantha@wipro.com Mantha et al. Expires Nov 2002 [Page 7] Internet Draft draft-mantha-resource-class-crldp-00.txt May 2002 Nagabhushana Ramaswamy Wipro Technologies K-312, 5th Block, Koramangala Bangalore-560095 India Phone : 91-80-5538301 Email : nagabhushana.ramaswamy@wipro.com Chetan Kumar S Wipro Technologies K-312, 5th Block, Koramangala Bangalore-560095 India Phone : 91-80-5538301 Email : chetan.kumar@wipro.com 11. Full Copyright Statement Copyright (C) The Internet Society (date). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. Mantha et al. Expires Nov 2002 [Page 8]