CCAMP C. Margaria, Ed. Internet-Draft Nokia Siemens Networks Intended status: Standards Track G. Martinelli Expires: August11,28, 2013 Cisco S. Balls B. Wright Metaswitch February07,24, 2013 LSP Attribute in EROdraft-ietf-ccamp-lsp-attribute-ro-00draft-ietf-ccamp-lsp-attribute-ro-01 Abstract LSP attributes can be specified or recorded for whole path, but they cannot be targeted to a specific hop. This document proposes alternative ways to extend the semantic for RSVP ERO object to target LSP attributes to a specific hop. Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. 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." This Internet-Draft will expire on August11,28, 2013. Copyright Notice Copyright (c) 2013 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. 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. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Contributing Authors . . . . . . . . . . . . . . . . . . . 3 1.2. Requirements Language . . . . . . . . . . . . . . . . . . 3 2. Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 4 3.Solutions . . . . . . . . .ERO LSP Attribute Subobject . . . . . . . . . . . . . . . . . 5 3.1.Non solution . . . . . . . . . . . . . . . . . . . . . . . 5 3.2. ExtendedEROObject . . . . . . . . . . . . .LSP_ATTRIBUTE subobject . . . . . .5 3.2.1. Semantic of the Extended ERO object. . . . . . . . . 53.2.2.3.2. Procedures . . . . . . . . . . . . . . . . . . . . . .5 3.2.3. Subobjects . . . . . . . . . . . . . . . . . . . .. . 63.2.4. Processing . . . . . . . . . . . . . . . . . . . . . . 94. IANA Considerations . . . . . . . . . . . . . . . . . . . . .117 5. Security Considerations . . . . . . . . . . . . . . . . . . .128 6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .139 7. References . . . . . . . . . . . . . . . . . . . . . . . . . .1410 7.1. Normative References . . . . . . . . . . . . . . . . . . .1410 7.2. Informative References . . . . . . . . . . . . . . . . . .1410 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . .1512 1. Introduction Generalized MPLS (GMPLS) Traffic Engineering (TE) Label Switched Paths (LSPs) can be route-constrained by making use of the Explicit Route (ERO) object and related sub-objects as defined in [RFC3209], [RFC3473], [RFC3477], [RFC4873], [RFC4874], [RFC5520] and [RFC5553].ThisThose route constraints are extended by a number of documents, including element defined in [RFC6163], [I-D.ietf-ccamp-wson-signaling], [I-D.dong-ccamp-rsvp-te-mpls-tp-li-lb] or [I-D.ali-ccamp-rc-objective-function-metric-bound]. RSVP already supports generic extension of LSP attributes in [RFC5420]. In order to support current and future ERO constraint extensions this documentproposes mechanismsdefines a mechanism to target LSP attributes at a specific hop.This document presents several solutions for discussion, final document will contains only one document after WG consensus.1.1. Contributing Authors 1.2. Requirements Language 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]. 2. Requirements The requirement is to provide a generic mechanism to carry information related to specific nodes when signaling an LSP. This document does not restrict what that information can be used for. LSP attribute defined [RFC5420] should be expressed in ERO and SERO objects. 3.Solutions 3.1. Non solution A solution using a specificERO LSP Attribute Subobject The ERO LSP Attributes subobject may be carried in the ERO or SERO object if they are present. The subobjectis not used becauseuses thesubobject length is limited to 8 bit, versus 16 bit for LSP ATTRIBUTES. This does not allow to put LSP ATTRIBUTE subobjects instandard format of an EROsubobjects. 3.2. Extendedsubobject. 3.1. EROObjectLSP_ATTRIBUTE subobject Thelogic of the EXTENDED_EXPLICIT_ROUTE followslength is variable and content MUST be theone of SERO.The class ofsame as for theEXTENDED_EXPLICIT_ROUTELSP_ATTRIBUTE objectis xxx (of the form 11bbbbbb).with Attributes TLVs. TheEXTENDED_EXPLICIT_ROUTE object hassize of thefollowing format: Class = xxx, C_Type = 1 The EXTENDED_EXPLICIT_ROUTEERO sub- objectmay be used if some node alonglimits theexplicit route support this object. The EXTENDED_EXPLICIT_ROUTE object is assigned a class valuesize of theform 11bbbbbb, so itLSP Attribute TLV to 250 bytes. The typical size of currently defined and forthcoming LSP_ATTRIBUTE TLVs applicable to a specific hop (WSON_SIGNALING, OF and Metric) isforwarded by nodesnotsupporting it. 0foreseen to exceed this limit. The ERO LSP attribute subobject is defined as follows: 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 | Reserved |R| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | //(Subobjects)Attributes TLVs // | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+Subobjects The contents of an EXTENDED_EXPLICIT_ROUTE object areSee [RFC3209] for aseriesdescription ofvariable- length data items called subobjects.L parameters. Thesubobjectsattributes TLV are encoded as defined in [RFC5420] sectionSection 3.2.3 below. 3.2.1. Semantic of the Extended ERO object Extended ERO object is carried in Path messages and carries a list of hops extended with hop-specific information. It is structured as a sequence of hop identifier subobjects (to indicate the hop who should process the subsequent attributes) and a series of hop attributes (which may be mandatory or optional) for the specified hop to process. 3.2.2. Procedures If a Path message contains multiple EXTENDED_EXPLICIT_ROUTE objects, only the first object is meaningful. Subsequent EXTENDED_EXPLICIT_ROUTE objects MAY be ignored and SHOULD NOT be propagated. An EXTENDED_EXPLICIT_ROUTE SHOULD contain at least 2 subobjects. The first subobject MUST indicate a node or link that identifies a hop that should process the next subobject(s). The address used to identify the hop SHOULD also be listed in the ERO or an SERO. This ensures that the extended attribute is for a node or link along the LSP path. The second subobject SHOULD contains an extended node or link information. In this document this SHOULD be a LSP Attribute subobject. 3.2.3. Subobjects The content of an EXTENDED_EXPLICIT_ROUTE are a series of variable length subobjects. Each subobject has the following form 0 1 2 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--------//-----------+ | Type | Length | (Subobject contents)| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--------//-----------+ The3. Typeindicates the type of contents of the subobject. Currently defined values are: 1 Hop identifier subobject containing an ERO subobject: IPv4 prefix IPv6 prefix Unnumbered Interface ID Autonomous system number Path Key with 32-bit PCE ID Path Key with 128-bit PCE ID Per-hop attributes: XX LSP Attributex TBD by IANA. Length The Length contains the total length of the subobject in bytes, including the Type and Length.fields. The Length MUST beat least 4, andalways divisible by 4. Reserved Reserved, must be set to 0 when the subobject is inserted in the ERO, MUST NOT be changed when amultiple of 4. 3.2.3.1. Hop identifier The Hop identifier subobject contains exactly one ERO subobject identifying a hop. The value of the subobject is a copy of the ERO subobject definition. The format of the subobject is as follow: 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 |L| sub Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sub Length | (Subobject contents) ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type 0x01 Hop Identifier Length The Length contains the total length of the subobject in bytes, including the Type and Length fields. Sub type The ERO subobject type, the same as the ERO subobject type. the ERO type defined are : 1 IPv4 prefix 2 IPv6 prefix 3 Reserved 4 Unnumbered Interface ID 32 Autonomous system number 33 Reserved 37 Reserved 64 Path Key with 32-bit PCE ID 65 Path Key with 128-bit PCE ID Sub length The ERO subobject type, the same as the ERO subobject length. It its unchanged compared to the ERO subobject definition. Subobject contents The ERO subobject content, it its unchanged compared to the ERO subobject definition. 3.2.3.2. Hop LSP Attribute The LSP attribute subobject contains information targeted at the hop identified by the preceding hop identifier 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | Reserved |R| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | // Attributes TLVs // | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The attributes TLV are encoded as defined in [RFC5420] section 3. Type x TBD by IANA. Length The Length contains the total length of the subobject in bytes, including the Type and Length fields. The Length MUST be always divisible by 4. Reserved Reserved, must be set to 0 when the subobject is inserted in the ERO, MUST NOT be changed when a node process the ERO and must be ignored on the node addressed by the preceding ERO subobjects R This bit reflects the LSP_REQUIRED_ATTRIBUTE and LSP_ATTRIBUTE semantic. When set indicates required LSP attributes to be processed by the node, when cleared the LSP attributes are not required as described in Section 3.2.3.3. 3.2.3.3. Processing Following [RFC3209] and [RFC3473] the Extended ERO is managed as a list where each hop information starts with a subobject identifying an abstract node or link. The LSP attribute subobject must be appended after the hop identifier subobject (which follows the formatting ofnode process theobjects defined in [RFC3209], [RFC3473], [RFC3477], [RFC4873], [RFC4874], [RFC5520]ERO and[RFC5553]. Several LSP attribute subobject MAYmust bepresent for each hop identification object. When the R bit is set a node MUST examine the attribute TLV present in the subobject following the rules described in [RFC5420] section 5.2. Whenignored on theR bit is not set anodeMUST examine the attribute TLV present in the subobject followingaddressed by therules described in [RFC5420] section 4.2. If more than onepreceding EROLSP attribute subobject having thesubobjects. R This bitset is present,reflects thefirst one MUST be processedLSP_REQUIRED_ATTRIBUTE andthe others SHOULD be ignored. If more than one EROLSP_ATTRIBUTE semantic. When set indicates required LSPattribute subject having the R bit cleared is present for the same hop identification object, then the first one MUSTattributes to be processedand the others SHOULD be ignored. 3.2.4. Processing A node receiving a Path message containing an EXTENDED_EXPLICIT_ROUTE object must determine if the extended hop information is applicable for this node. The node performs the following steps: 1. The node receiving the RSVP message MUST first evaluate if the ERO object is present. If the ERO object is not present it has received the message in error and SHOULD return a pathError message. 2. Second the node MUST readby thefirst subobject. Ifnode, when cleared thenode isLSP attributes are notpart of the abstract noderequired as describedby the first subobject, the processing stops.in Section 3.2. Attributes TLVs as defined in [RFC5420] section 3.If there is no second subobject this indicates the end of the extended ERO. The extended ERO SHOULD be removed from the Path message. A new extended ERO MAY be added to the Path message. 4. Next the node evaluates the second subobject. A. If the subobject identified an abstract node3.2. Procedures As described in [RFC3209] and [RFC3473] thenodeERO isalso part of the abstract node, then the node deletes the first subobject and continue processingmanaged as a list where each hop information starts withstep 3. B. If thea subobjectidentifiedidentifying an abstract nodeandor link. The LSP attribute subobject must be appended after the existing subobjects defined in [RFC3209], [RFC3473], [RFC3477], [RFC4873], [RFC4874], [RFC5520] and [RFC5553]. Several LSP attribute subobject MAY be present, for each hop. If a node is processing an LSP attribute subobject and does notpartsupport handling of theabstract node, then the extendedsubobject it will behave as described in [RFC3209] when an unrecognized ERO subobject isinvalid and theencountered. This nodeSHOULDwill return a PathErr with error code "Routing Error" and error value "BadEXTENDED_EXPLICIT_ROUTEEXPLICIT_ROUTE object" with theEXTENDED_EXPLICIT_ROUTEEXPLICIT_ROUTE object included, truncated (on the left) to the offending unrecognizedsubobject C. Ifsubobject. When thesubobjectR bit isan LSP Attribute subobject it processes it according toset a node MUST examine the attribute TLV present in therules for thatsubobjectand removes it fromfollowing theextended ERO. Ifrules described in [RFC5420] section 5.2. When theextended ERO doesR bit is notcontain further subject it SHOULD be removed from the Path message. A new extended ERO MAY be added to the Path message. Ifset a nodefinds a hop identification object which matchesMUST examine thelocal router handling ofattribute TLV present in the subobjectit will behave asfollowing the rules described in[RFC3209] when[RFC5420] section 4.2. A node processing anunrecognizedLSP attribute subobject with an LSP_ATTRIBUTE TLV longer than the ERO subobjectis encountered. This node willSHOULD return a PathErr with error code "Routing Error" and error value "BadEXTENDED_EXPLICIT_ROUTEEXPLICIT_ROUTE object" with theEXTENDED_EXPLICIT_ROUTEEXPLICIT_ROUTE object included, truncated (on the left) to the offendingunrecognizedmalformed subobject. The processing of the LSP_ATTRIBUTE TLVs should be described in the documents defining them. 4. IANA Considerations TBD once a final approach has been chosen. 5. Security Considerations None. 6. Acknowledgments The authors would like to thanks Lou Berger for his directions and Attila Takacs for inspiring this [I-D.kern-ccamp-rsvpte-hop-attributes]. The authors also thanks Dirk Schroetter for his contribution to the initial versions of the documents (version -00 up to -02). 7. References 7.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP Tunnels", RFC 3209, December 2001. [RFC3473] Berger, L., "Generalized Multi-Protocol Label Switching (GMPLS) Signaling Resource ReserVation Protocol-Traffic Engineering (RSVP-TE) Extensions", RFC 3473, January 2003. [RFC3477] Kompella, K. and Y. Rekhter, "Signalling Unnumbered Links in Resource ReSerVation Protocol - Traffic Engineering (RSVP-TE)", RFC 3477, January 2003. [RFC4873] Berger, L., Bryskin, I., Papadimitriou, D., and A. Farrel, "GMPLS Segment Recovery", RFC 4873, May 2007. [RFC4874] Lee, CY., Farrel, A., and S. De Cnodder, "Exclude Routes - Extension to Resource ReserVation Protocol-Traffic Engineering (RSVP-TE)", RFC 4874, April 2007. [RFC5420] Farrel, A., Papadimitriou, D., Vasseur, JP., and A. Ayyangarps, "Encoding of Attributes for MPLS LSP Establishment Using Resource Reservation Protocol Traffic Engineering (RSVP-TE)", RFC 5420, February 2009. [RFC5520] Bradford, R., Vasseur, JP., and A. Farrel, "Preserving Topology Confidentiality in Inter-Domain Path Computation Using a Path-Key-Based Mechanism", RFC 5520, April 2009. [RFC5553] Farrel, A., Bradford, R., and JP. Vasseur, "Resource Reservation Protocol (RSVP) Extensions for Path Key Support", RFC 5553, May 2009. 7.2. Informative References [I-D.ali-ccamp-rc-objective-function-metric-bound] Ali, Z., Swallow, G., Filsfils, C., Fang, L., Kumaki, K., and R. Kunze, "Resource ReserVation Protocol-Traffic Engineering (RSVP-TE) extension for signaling Objective Function and Metric Bound", draft-ali-ccamp-rc-objective-function-metric-bound-02 (work in progress), July 2012. [I-D.dong-ccamp-rsvp-te-mpls-tp-li-lb] Dong, J., Chen, M., and Z. Li, "GMPLS RSVP-TE Extensions for Lock Instruct and Loopback", draft-dong-ccamp-rsvp-te-mpls-tp-li-lb-05 (work in progress), December 2012. [I-D.ietf-ccamp-wson-signaling] Bernstein, G., Xu, S., Lee, Y., Martinelli, G., and H. Harai, "Signaling Extensions for Wavelength Switched Optical Networks", draft-ietf-ccamp-wson-signaling-05 (work in progress), February 2013. [I-D.kern-ccamp-rsvpte-hop-attributes] Kern, A. and A. Takacs, "Encoding of Attributes of LSP intermediate hops using RSVP-TE", draft-kern-ccamp-rsvpte-hop-attributes-00 (work in progress), October 2009. [RFC6163] Lee, Y., Bernstein, G., and W. Imajuku, "Framework for GMPLS and Path Computation Element (PCE) Control of Wavelength Switched Optical Networks (WSONs)", RFC 6163, April 2011. Authors' Addresses Cyril Margaria (editor) Nokia Siemens Networks St Martin Strasse 76 Munich, 81541 Germany Phone: +49 89 5159 16934 Email: cyril.margaria@nsn.com Giovanni Martinelli Cisco via Philips 12 Monza 20900 IT Phone: +39 039 209 2044 Email: giomarti@cisco.com Steve Balls Metaswitch 100 Church Street Enfield EN2 6BQ UJ Phone: +44 208 366 1177 Email: steve.balls@metaswitch.com Ben Wright Metaswitch 100 Church Street Enfield EN2 6BQ UJ Phone: +44 208 366 1177 Email: Ben.Wright@metaswitch.com