Networking Working Group Internet Draft Anca Zamfir, Zafar Ali Cisco Systems D. Papadimitriou Alcatel Document: draft-zamfir-explicit-resource- control-bundle-02.txt Expires: April 2004 October 2003 Component Link Recording and Resource Control for GMPLS Link Bundles draft-zamfir-explicit-resource-control-bundle-02.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 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. Abstract Record Route is a useful administrative tool that has been used extensively by the service providers. When TE links are bundled, identification of label resource in RRO is not enough for the administrative purpose. Network service providers would like to know the component link within a TE link that is being used by a given LSP. In other words, when link bundling is used, resource recording Zamfir, A., Ali, Z., Papadimitroiu, D. [Page 1] draft-zamfir-explicit-resource-control-bundle-01.txt October 2003 requires mechanisms to specify the component link identifier, along with the TE link identifier and Label. However, it is not possible to record component link in the RRO. This draft defines the extensions to RSVP-TE [RFC3209] to specify component link identifiers for resource recording purposes. In this draft, we also define ERO counterpart of the RRO extension. The ERO extensions are needed to perform explicit label/ resource control over bundled TE link. In summary, this draft defines the extensions to RSVP-TE [RFC3209] to specify component link identifiers for explicit resource control and recording over GMPLS link bundles. 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]. Sub-IP ID Summary (This section to be removed before publication.) SUMMARY This document specifies extensions and mechanisms to RSVP-TE to provide resource recording and control over GMPLS Link Bundles. WHERE DOES IT FIT IN THE PICTURE OF THE SUB-IP WORK? This work fits in the MPLS box. WHY IS IT TARGETED AT THIS WG? This draft is targeted at this WG, because this it specifies extensions to RSVP-TE signaling protocol for explicit resource control over GMPLS Link Bundles [BUNDLE]. RELATED REFERENCES Please refer to the reference section. Table of Contents 1. Terminology....................................................3 2. Explicit Resource Control......................................3 3. LSP Resource Recording.........................................4 Zamfir, A., Ali, Z., Papadimitroiu, D. [Page 2] draft-zamfir-explicit-resource-control-bundle-01.txt October 2003 3.1 Component Interface Identifier RRO subobject...............4 3.2 Processing of Component Interface identifier RRO Subobject.5 4. Signaling Component Interface Identifier in ERO................6 4.1 Processing of Component Interface Identifier ERO Subobject.7 5. Forward Compatibility Note.....................................9 6. Security Considerations........................................9 References........................................................9 Author's Addresses...............................................10 1. Terminology TE Link - Unless specified otherwise, it refers to a bundled Traffic Engineering link as defined in [BUNDLE]. Furthermore, the terms TE Link and bundled TE Link are used interchangeably in this draft. Component Interface - Refers to a component link in a bundled TE link. Component Interface Identifier - Refers to an ID used to uniquely identify a Component Interface. 2. Resource Control and Recording In classical MPLS that deals with unbundled packet switch capable TE Links, one of the types of resources that an LSP originator can control and would like to record are the TE Link interfaces used by the LSP. The resource control and recording is done by the use of an explicit route, i.e., ERO Object and Record Route, i.e., RRO object, respectively. Link Bundling introduced by [BUNDLE], is used to improve routing scalability by reducing the amount of TE related information that needs to be flooded and handled by IGP in a TE network. This is accomplished by aggregating and abstracting the TE Link resource. In some cases the complete resource identification is left as a local decision. However, as described above there are cases when it is desirable for a non-local (e.g., LSP Head-end) node to identify completely or partially the LSP resources. In either case, for administrative reasons, it is required to know which component link within a bundled TE link has been used for a given LSP. When link bundling is used to aggregate multiple component links into a TE link, label is not the only resource that needs to be identified and recorded. In other words, the TE Link and the Label specified in the ERO/ RRO objects are not enough to completely identify the resource. For the bundled TE link case, in order to fully specify the resources on a link for a given LSP, the component link needs to be specified along with the label. In the case of bi- directional LSPs both upstream and downstream information may be Zamfir, A., Ali, Z., Papadimitroiu, D. [Page 3] draft-zamfir-explicit-resource-control-bundle-01.txt October 2003 specified. Therefore, explicit resource control and recording over a bundled TE link also requires ability to specify a component link within the TE link. This draft defines extensions to and describes the use of RSVP-TE [FC3209], [RFC3471], [RFC3473] to specify the component link identifier for resource recording and explicit resource control over GMPLS link bundles. Specifically, in this draft, component interface identifier RRO and ERO subobjects are defined to complement their Label RRO and ERO counterparts. Furthermore, procedures for processing component interface identifier RRO and ERO subobjects and how they can co-exist with the Label RRO and ERO subobjects are specified. 3. LSP Resource Recording This refers to the ability to record the resources used by an LSP. The procedure for unbundled numbered TE links is described in [RFC3209] and for unbundled unnumbered TE links in [RFC 3477]. For the purpose of recording LSP resources used over bundled TE Links, the Component Interface Identifier RRO sub-object is introduced. 3.1 Component Interface Identifier RRO subobject A new subobject of the Record Route Object (RRO) is used to record component interface identifier of a (bundled) TE Link. This subobject has the following format: Figure 2: Component Interface Identifier RRO subobject 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |L| Type | Length |U| Reserved (must be zero) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Component Interface Identifier | | . . . | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 0 1 2 3 L: 1 bit This bit must be set to 0. Type Zamfir, A., Ali, Z., Papadimitroiu, D. [Page 4] draft-zamfir-explicit-resource-control-bundle-01.txt October 2003 10 (TBD) Component Interface identifier IPv4 11 (TBD) Component Interface identifier IPv6 12 (TBD) Component Interface identifier Unnumbered Length The Length contains the total length of the subobject in bytes, including the Type and Length fields. The Length is 8 bytes for the Component Interface identifier IPv4 and Component Interface identifier Unnumbered types. For Component Interface identifier IPv6 type of sub-object, the length field is 20 bytes. U: 1 bit This bit indicates the direction of the component interface. It is 0 for the downstream interface. It is set to 1 for the upstream interface and is only used for bi-directional LSPs. 3.2 Processing of Component Interface identifier RRO Subobject If a node desires component link recording, the "Component Link Recording desired" flag (value TBD) should be set in the LSP_ATTRIBUTES object, object that is defined in [RSVP-TE-ATTRIBUTE]. Setting of "Component Link Recording desired" flag is independent of the Label Recording flag in SESSION_ATTRIBUTE object as specified in [RFC3209]. Nevertheless, the following combinations are valid: 1) If both Label and Comp Link flags are clear, then neither Labels nor Component Links are recorded. 2) If Label Recording flag is set and Component Link flag is clear, then only Label Recording is performed as defined in [RFC3209]. 3) If Label Recording flag is clear and Component Link flag is set, then Component Link Recording is performed as defined in this proposal. 4) If both Label Recording and Component Link flags are set, then Label Recording is performed as defined in [RFC3209] and also Component Link recording is performed as defined in this proposal. In most cases a node initiates recording for a given LSP by adding the RRO to the Path message. If the node desires Component Link recording and if the outgoing TE link is bundled, then the initial RRO contains the Component Link identifier (numbered or unnumbered) as selected by the sender. As well, the Component Link Recording desired flag is set in the LSP_ATTRIBUTE object. If the node also desires label recording, it sets the Label_Recording flag in the SESSION_ATTRIBUTE object. Zamfir, A., Ali, Z., Papadimitroiu, D. [Page 5] draft-zamfir-explicit-resource-control-bundle-01.txt October 2003 When a Path message with the "Component Link Recording desired" flag set is received by an intermediate node, if a new Path message is to be sent for a downstream bundled TE link, the node adds a new Component Link subobject to the RRO and appends the resulting RRO to the Path message before transmission. Note that, unlike Labels, Component Link identifiers are always known on receipt of the Path message. When the destination node of an RSVP session receives a Path message with an RRO and the "Component Link Recording desired" flag set, this indicates that the sender node needs TE route as well as component link recording. The destination node initiates the RRO process by adding an RRO to Resv messages. The processing mirrors that of the Path messages The Component Interface Record subobject is pushed onto the RECORD_ROUTE object prior to pushing on the node's IP address. A node MUST NOT push on a Component Interface Record subobject without also pushing on the IP address or unnumbered Interface Id subobject that identifies the TE Link. When component interfaces are recorded for bi-directional LSPs, component interface RRO subobjects for both downstream and upstream interfaces MUST be included. 4. Signaling Component Interface Identifier in ERO A new OPTIONAL subobject of the EXPLICIT_ROUTE Object (ERO) is used to specify component interface identifier of a bundled TE Link. This subobject has the following format: Figure 1: Component Interface Identifier ERO subobject 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |L| Type | Length |U| Reserved (MUST be zero) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv4, IPv6 or unnumbered Component Interface Identifier | | . . . | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ L: 1 bit This bit must be set to 0. Zamfir, A., Ali, Z., Papadimitroiu, D. [Page 6] draft-zamfir-explicit-resource-control-bundle-01.txt October 2003 Type 10 (TBD) Component Interface identifier IPv4 11 (TBD) Component Interface identifier IPv6 12 (TBD) Component Interface identifier Unnumbered Length The Length contains the total length of the subobject in bytes, including the Type and Length fields. The Length is 8 bytes for the Component Interface identifier types: IPv4 and Component Interface identifier Unnumbered. For Component Interface identifier IPv6 type of sub-object, the length field is 20 bytes. U: 1 bit This bit indicates the direction of the component interface. It is 0 for the downstream interface. It is set to 1 for the upstream interface and is only used for bi-directional LSPs. 4.1 Processing of Component Interface Identifier ERO Subobject The Component Interface Identifier ERO subobject follows a subobject containing the IP address, or the link identifier [RFC3477], associated with the TE link on which it is to be used. It is used to identify the component of a bundled TE Link. The following SHOULD result in "Bad EXPLICIT_ROUTE object" error being sent upstream by a node processing an ERO that contains the Component Interface ID sub-object: o The first component interface identifier subobject is not preceded by a sub-object containing an IPv4 or IPv6 address, or an interface identifier [RFC3477], associated with a TE link. o The Component Interface Identifier ERO subobject follows a subobject that has the L-bit set. o On unidirectional LSP setup, there is a Component Interface Identifier ERO subobject with the U-bit set. o Two Component Interface Identifier ERO subobjects with the same U-bit values exist. If a node implements the component interface identifier subobject, it must check if it represents a component interface in the bundled TE Link specified in the preceding subobject that contains the IP address or interface identifier of the TE Link. If the content of the Zamfir, A., Ali, Z., Papadimitroiu, D. [Page 7] draft-zamfir-explicit-resource-control-bundle-01.txt October 2003 component interface identifier subobject does not match a component interface in the TE link, a "Bad EXPLICIT_ROUTE object" error SHOULD be reported as "Routing Problem" (error code 24). If U-bit of the subobject being examined is cleared (0) and the upstream interface specified in this subobject is acceptable, then the value of the upstream component interface is copied in the TLV of the IF_ID HOP object [RFC 3471] and the local decision normally used to select the upstream component link is bypassed. If this interface is not acceptable, a "Bad EXPLICIT_ROUTE object" error SHOULD be reported as "Routing Problem" (error code 24). If the U-bit of the subobject being examined is set (1), then the value represents the component interface to be used for upstream traffic associated with the bidirectional LSP. Again, if this interface is not acceptable or if the request is not one for a bidirectional LSP, then a "Bad EXPLICIT_ROUTE object" error SHOULD be reported as "Routing Problem" (error code 24). Otherwise, the component interface IP address/ identifier is copied into a TLV sub- object as part of the IF_ID RSVP_HOP object. The IF_ID RSVP_HOP object constructed as above MUST be included in the corresponding outgoing Path message. Note that, associated with a TE Link sub-object in the ERO, either the upstream component interface or the downstream component interface or both may be specified. As specified in [BUNDLE] there is no relationship between the TE Link type (numbered or unnumbered) and the Link type of any one of its components. The component interface identifier ERO subobject is optional. Similarly, presence of the Label ERO sub-objects is not mandatory [RFC 3471], [RFC 3473]. Furthermore, component interface identifier ERO subobject and Label ERO subobject may be included in the ERO independently of each other. One of the following alternatives applies: o When both sub-objects are absent, a node may select any appropriate component link within the TE link and any label on the selected component link. o When the Label subobject is only present for a bundled link, then the selection of the component link within the bundle is a local decision and the node may select any appropriate component link, which can assume the label specified in the Label ERO. o When only the component interface identifier ERO subobject is present, a node MUST select the component interface specified in the ERO and may select any appropriate label value at the specified component link. o When both component interface identifier ERO subobject and Label ERO subobject are present, the node MUST select the specified component link and the specified label value on that component link. Zamfir, A., Ali, Z., Papadimitroiu, D. [Page 8] draft-zamfir-explicit-resource-control-bundle-01.txt October 2003 When present, both subobjects may appear in any relative order to each other but they MUST appear after the TE Link sub-object that they refer to. After processing, the component interface identifier subobjects are removed from the ERO. Inferred from above, the interface subobject should never be the first subobject in a newly received message. If the component interface subobject is the first subobject in a received ERO, then it SHOULD be treated as a "Bad strict node" error. Note: Information to construct the Component Interface ERO subobject may come from the same mean used to populate the label ERO subobject. Procedures by which an LSR at the head-end of an LSP obtains the information needed to construct the Component Interface subobject are outside the scope of this document. 5. Forward Compatibility Note The extensions specified in this draft do not affect the processing of the RRO, ERO at nodes that do not support them. A node that does not support the Component Interface RRO subobject but that does support Label subobject SHOULD only insert the Label subobject in the RRO as per [RFC3471] and [RFC3473]. A node that receives an ERO that contains a Component Link ID subobject SHOULD send "Bad EXPLICIT_ROUTE object" if it does not implement this subobject. As per [RFC3209], Section 4.4.5, a non-compliant node that receives an RRO that contains Component Interface Identifier sub-objects should ignore and pass them on. 6. Security Considerations This document does not introduce new security issues. The security considerations pertaining to the original RSVP protocol [RFC2205] remain relevant. References Zamfir, A., Ali, Z., Papadimitroiu, D. [Page 9] draft-zamfir-explicit-resource-control-bundle-00.txt October 2003 [RFC2205] " Resource ReSerVation Protocol (RSVP) - Version 1, Functional Specification", RFC 2205, Braden, et al, September 1997. [RFC3209] "Extensions to RSVP for LSP Tunnels", D. Awduche, et al, RFC 3209, December 2001. [BUNDLE] "Link Bundling in MPLS Traffic Engineering", draft-ietf- mpls-bundle-04.txt, K. Kompella, et al, January 2003. [RFC3471] Generalized Multi-Protocol Label Switching (GMPLS) Signaling Functional Description, RFC 3471, L. Berger, et al, January 2003. [RFC3473] "Generalized Multi-Protocol Label Switching (GMPLS) Signaling Resource ReserVation Protocol-Traffic Engineering (RSVP- TE) Extensions", RFC 3471, L. Berger, et al, January 2003. [RFC3477] "Signaling Unnumbered Links in Resource ReSerVation Protocol - Traffic Engineering (RSVP-TE) ", RFC 3477, K. Kompella, Y. Rekhter, January 2003. [RFC2119] "Key words for use in RFCs to Indicate Requirement Levels", RFC 2119, S. Bradner, March 1997. [RSVP-TE-ATTRIBUTE] "Encoding of Attributes for Multiprotocol Label Switching (MPLS) Label Switched Path (LSP) Establishment Using RSVP-TE", draft-farrel-mpls-rsvpte-attributes-00.txt., A. Farrel. et al, April 2004 Author's Addresses Anca Zamfir Cisco Systems Inc. 2000 Innovation Dr., Kanata, Ontario, K2K 3E8 Canada. Phone: (613)-254-3484 Email: ancaz@cisco.com Zafar Ali Cisco Systems Inc. 100 South Main St. #200 Ann Arbor, MI 48104 USA. Phone: (734) 276-2459 Email: zali@cisco.com Dimitri Papadimitriou (Alcatel) Fr. Wellesplein 1, B-2018 Antwerpen, Belgium Phone: +32 3 240-8491 Zamfir, A., Ali, Z. [Page 10] draft-zamfir-explicit-resource-control-bundle-00.txt October 2003 Email: dimitri.papadimitriou@alcatel.be Zamfir, A., Ali, Z. [Page 11]