--- 1/draft-ietf-teas-p2mp-loose-path-reopt-02.txt 2015-05-25 16:14:57.645699021 -0700 +++ 2/draft-ietf-teas-p2mp-loose-path-reopt-03.txt 2015-05-25 16:14:57.677699802 -0700 @@ -1,48 +1,48 @@ -TEAS Working Group Tarek Saad, Ed. -Internet-Draft Rakesh Gandhi, Ed. -Intended status: Standards Track Zafar Ali -Expires: September 10, 2015 Cisco Systems, Inc. - Robert H. Venator +TEAS Working Group T. Saad, Ed. +Internet-Draft R. Gandhi, Ed. +Intended status: Standards Track Z. Ali +Expires: November 26, 2015 Cisco Systems, Inc. + R. Venator Defense Information Systems Agency - Yuji Kamite + Y. Kamite NTT Communications Corporation - March 9, 2015 + May 25, 2015 - Extensions to Resource Reservation Protocol For Re-optimization - of Loosely Routed Point-to-Multipoint Traffic Engineering LSPs - draft-ietf-teas-p2mp-loose-path-reopt-02 + RSVP Extensions For Re-optimization of Loosely Routed + Point-to-Multipoint Traffic Engineering Label Switched Paths (LSPs) + draft-ietf-teas-p2mp-loose-path-reopt-03 Abstract For a Traffic Engineered (TE) Point-to-Multipoint (P2MP) Label Switched Path (LSP), it is preferable in some cases to re-evaluate and re-optimize the entire P2MP-TE LSP by re-signaling all its Source-to-Leaf (S2L) sub-LSP(s). Existing mechanisms, a mechanism - for an ingress Label Switched Router (LSR) to trigger a new path re- - evaluation request and a mechanism for a mid-point LSR to notify an - availability of a preferred path, operate on an individual or a + for an ingress Label Switched Router (LSR) to trigger a new path + re-evaluation request and a mechanism for a mid-point LSR to notify + an availability of a preferred path, operate on an individual or a sub-group of S2L sub-LSP(s) basis only. - This document defines RSVP-TE signaling extensions to allow an - ingress node of a P2MP-TE LSP to request the re-evaluation of the - entire LSP tree containing one or more S2L sub-LSPs whose paths are - loose (or abstract) hop expanded, and for a mid-point LSR to notify - to the ingress node that a preferable tree exists for the entire - P2MP-TE LSP. For re-optimizing a group of S2L sub-LSP(s) in a tree, - an S2L sub-LSP descriptor list can be used to signal one or more S2L - sub-LSPs in an RSVP message. This document defines markers to - indicate beginning and end of an S2L sub-LSP descriptor list when the - RSVP message needs to be fragmented due to large number of S2L - sub-LSPs in the message when performing sub-group based - re-optimization. + This document defines Resource Reservation Protocol (RSVP) signaling + extensions to allow an ingress node of a P2MP-TE LSP to request the + re-evaluation of the entire LSP tree containing one or more S2L + sub-LSPs whose paths are loose (or abstract) hop expanded, and for a + mid-point LSR to notify to the ingress node that a preferable tree + exists for the entire P2MP-TE LSP. For re-optimizing a group of S2L + sub-LSP(s) in a tree, an S2L sub-LSP descriptor list can be used to + signal one or more S2L sub-LSPs in an RSVP message. This document + defines markers to indicate beginning and end of an S2L sub-LSP + descriptor list when the RSVP message needs to be fragmented due to + large number of S2L sub-LSPs in the message when performing sub-group + based re-optimization. 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/. @@ -81,29 +81,29 @@ 2.3. Nomenclatures . . . . . . . . . . . . . . . . . . . . . . 8 3. Signaling Procedure For Loosely Routed P2MP-TE LSP Re-optimization . . . . . . . . . . . . . . . . . . . . . . . 8 3.1. Tree-Based Re-optimization . . . . . . . . . . . . . . . . 8 3.2. Sub-Group-Based Re-optimization Using Markers . . . . . . 9 4. Message and Object Definitions . . . . . . . . . . . . . . . . 10 4.1. P2MP-TE Tree Re-evaluation Request Flag . . . . . . . . . 10 4.2. Preferable P2MP-TE Tree Exists Path Error Sub-code . . . . 10 4.3. Markers For S2L sub-LSP Descriptor . . . . . . . . . . . . 11 5. Compatibility . . . . . . . . . . . . . . . . . . . . . . . . 11 - 6. Security Considerations . . . . . . . . . . . . . . . . . . . 12 - 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 - 7.1. P2MP-TE Tree Re-evaluation Request Flag . . . . . . . . . 12 - 7.2. Preferable P2MP-TE Tree Exists Path Error Sub-code . . . . 13 - 7.3. BEGIN and END Markers For S2L sub-LSP Descriptor . . . . . 13 - 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 14 - 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 15 - 9.1. Normative References . . . . . . . . . . . . . . . . . . . 15 - 9.2. Informative References . . . . . . . . . . . . . . . . . . 15 + 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 + 6.1. P2MP-TE Tree Re-evaluation Request Flag . . . . . . . . . 12 + 6.2. Preferable P2MP-TE Tree Exists Path Error Sub-code . . . . 12 + 6.3. BEGIN and END Markers For S2L sub-LSP Descriptor . . . . . 13 + 7. Security Considerations . . . . . . . . . . . . . . . . . . . 14 + 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 15 + 8.1. Normative References . . . . . . . . . . . . . . . . . . . 15 + 8.2. Informative References . . . . . . . . . . . . . . . . . . 15 + Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 16 Author's Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16 1. Introduction This document defines Resource Reservation Protocol - Traffic Engineering (RSVP-TE) [RFC2205] [RFC3209] signaling extensions for re-optimizing loosely routed Point-to-Multipoint (P2MP) Traffic Engineered (TE) Label Switched Paths (LSPs) [RFC4875] in an Multi-Protocol Label Switching (MPLS) and/or Generalized MPLS (GMPLS) networks. @@ -135,21 +135,21 @@ o An ingress node triggers a path re-evaluation request at all mid-point LSR(s) that expands loose next-hop(s) by setting the "Path Re-evaluation Request" flag (0x20) in SESSION_ATTRIBUTES Object in the Path message. o The ingress node upon receiving this PathErr either solicited or unsolicited initiates re-optimization of the LSP with a different LSP-ID. - Following Sections discuss the issues that may arise when using + Following sections discuss the issues that may arise when using existing mechanisms defined in [RFC4736] for re-optimizing loosely routed P2MP-TE LSPs. 1.1. Loosely Routed Inter-domain P2MP-TE LSP Tree An example of a loosely routed inter-domain P2MP-TE LSP tree is shown in Figure 1. In this example, the P2MP-TE LSP tree consists of 3 S2L sub-LSPs, to destinations (i.e. leafs) R10, R11 and R12 from the ingress node (i.e. source) R1. Nodes R2 and R5 are branch nodes and nodes ABR3, ABR4, ABR7, ABR8 and ABR9 are area border routers. For @@ -202,24 +202,24 @@ o The ingress node that receives (un)solicited PathErr notification(s) for individual S2L sub-LSP(s), may prematurely start re-optimizing the sub-set of S2L sub-LSPs. However, as mentioned in [RFC4875] Section 14.2, such sub-group based re-optimization procedure may result in data duplication that can be avoided if the entire P2MP-TE LSP tree is re-optimized using a different LSP-ID, especially if the ingress node eventually receives PathErr notifications for all S2L sub-LSPs of the P2MP-TE LSP tree. - In order to address above mentioned issues and to align re- - optimization of P2MP-TE LSP with P2P LSP [RFC4736], there is a need - for a mechanism to trigger re-optimization of the LSP tree by re- - signaling all S2L sub-LSPs with a different LSP-ID. To meet this + In order to address above mentioned issues and to align + re-optimization of P2MP-TE LSP with P2P LSP [RFC4736], there is a + need for a mechanism to trigger re-optimization of the LSP tree by + re-signaling all S2L sub-LSPs with a different LSP-ID. To meet this requirement, this document defines RSVP-TE signaling extensions for the ingress node to trigger the re-evaluation of the P2MP LSP tree on every hop that has a next-hop defined as a loose or abstract hop for one or more S2L sub-LSP path, and a mid-point LSR to signal to the ingress node that a preferable LSP tree exists (compared to the current path) or that the whole P2MP-TE LSP must be re-optimized (because of maintenance required on the TE LSP path). 1.3. Existing Mechanism For Sub-Group-Based P2MP-TE LSP Re-optimization @@ -264,23 +264,20 @@ of S2L sub-LSPs in an RSVP message. 2. Conventions Used in This Document 2.1. Key Word Definitions 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 [RFC2119]. - The reader is assumed to be familiar with the terminology in - [RFC4875] and [RFC4736]. - 2.2. Abbreviations ABR: Area Border Router. AS: Autonomous System. ERO: Explicit Route Object. LSR: Label Switching Router. @@ -299,20 +296,23 @@ Inter-area TE LSP: A TE LSP whose path transits across at least two different IGP areas. Inter-AS MPLS TE LSP: A TE LSP whose path transits across at least two different Autonomous Systems (ASes) or sub-ASes (BGP confederations). S2L sub-LSP: Source-to-leaf sub Label Switched Path. + The reader is assumed to be familiar with the terminology in + [RFC4875] and [RFC4736]. + 3. Signaling Procedure For Loosely Routed P2MP-TE LSP Re-optimization 3.1. Tree-Based Re-optimization To evaluate an entire P2MP-TE LSP tree on mid-point LSRs that expand loose next-hop(s), an ingress node MAY send a Path message with "P2MP-TE Tree Re-evaluation Request" defined in this document. The ingress node SHOULD select one of the S2L sub-LSPs of the P2MP-TE LSP tree transiting a mid-point LSR to trigger the re-evaluation request. The ingress node MAY send a re-evaluation request to each border LSR @@ -466,48 +466,26 @@ non-supporting nodes. Per [RFC2205], nodes not supporting this extension will ignore the new flag defined in this document but forward it without modification. The S2L_SUB_LSP_MARKER_BEGIN and S2L_SUB_LSP_MARKER_END Objects have been defined with class numbers in the form 11bbbbbb, which ensures compatibility with non-supporting nodes. Per [RFC2205], nodes not supporting new S2L_SUB_LSP_MARKER_BEGIN and S2L_SUB_LSP_MARKER_END Objects will ignore them but forward it without modification. -6. Security Considerations - - This document defines RSVP-TE signaling extensions to allow an - ingress node of a P2MP-TE LSP to request the re-evaluation of the - entire LSP tree, and for a mid-point LSR to notify the ingress node - of the existence of a preferable tree by sending a PathErr. As per - [RFC4736], in the case of a P2MP-TE LSP S2L sub-LSP spanning multiple - domains, it may be desirable for a mid-point LSR to modify the RSVP - PathErr message defined in this document to preserve confidentiality - across domains. Furthermore, an ingress node may decide to ignore - this PathErr message coming from a mid-point LSR residing in another - domain. Similarly, a mid-point LSR may decide to ignore the P2MP-TE - tree re-evaluation request originating from another ingress domain. - - This document also defines markers to indicate beginning and end of - an S2L sub-LSP descriptor list when combining large number of S2L - sub-LSPs in an RSVP message and the message needs to be fragmented. - The introduction of these markers, by themselves, introduce no - additional information to signaling. For a general discussions on - MPLS and GMPLS related security issues, see the MPLS/GMPLS security - framework [RFC5920]. - -7. IANA Considerations +6. IANA Considerations IANA is requested to administer assignment of new values for namespace defined in this document and summarized in this section. -7.1. P2MP-TE Tree Re-evaluation Request Flag +6.1. P2MP-TE Tree Re-evaluation Request Flag IANA maintains a name space for RSVP-TE TE parameters "Resource Reservation Protocol-Traffic Engineering (RSVP-TE) Parameters" (see http://www.iana.org/assignments/rsvp-te-parameters). From the registries in this name space "Attribute Flags", allocation of new flag is requested (Section 4.1). The following new flag is defined for the Attributes Flags TLV in the LSP_ATTRIBUTES Object [RFC5420]. The numeric value is to be assigned by IANA. @@ -515,21 +493,21 @@ o P2MP-TE Tree Re-evaluation Request Flag: +--------+---------------+---------+---------+---------+------------+ | Bit No | Attribute | Carried | Carried | Carried | Reference | | | Flag Name | in Path | in Resv | in RRO | | +--------+---------------+---------+---------+---------+------------+ | TBA by | P2MP-TE Tree | Yes | No | No | This | | IANA | Re-evaluation | | | | document | +--------+---------------+---------+---------+---------+------------+ -7.2. Preferable P2MP-TE Tree Exists Path Error Sub-code +6.2. Preferable P2MP-TE Tree Exists Path Error Sub-code IANA maintains a name space for RSVP protocol parameters "Resource Reservation Protocol (RSVP) Parameters" (see http://www.iana.org/assignments/rsvp-parameters). From the sub-registry "Sub-Codes - 25 Notify Error" in registry "Error Codes and Globally-Defined Error Value Sub-Codes", allocation of a new error code is requested (Section 4.2). As defined in [RFC3209], the Error Code 25 in the ERROR SPEC Object corresponds to a Notify Error PathErr. This document adds a new @@ -538,21 +516,21 @@ o Preferable P2MP-TE Tree Exists sub-code: +----------+--------------------+---------+---------+-----------+ | Sub-code | Sub-code | PathErr | PathErr | Reference | | value | Description | Code | Name | | +----------+--------------------+---------+---------+-----------+ | TBA by | Preferable P2MP-TE | 25 | Notify | This | | IANA | Tree Exists | | Error | document | +----------+--------------------+---------+---------+-----------+ -7.3. BEGIN and END Markers For S2L sub-LSP Descriptor +6.3. BEGIN and END Markers For S2L sub-LSP Descriptor IANA maintains a name space for RSVP protocol parameters "Resource Reservation Protocol (RSVP) Parameters" (see http://www.iana.org/assignments/rsvp-parameters). From the sub-registry "Class Types or C-Types 50 S2L_SUB_LSP" in registry "Class Names, Class Numbers, and Class Types", allocation of new C-Types is requested (Section 4.3). As defined in [RFC4875], S2L_SUB_LSP Object is defined with Class-Number 50 to identify a particular S2L sub-LSP belonging to the @@ -562,82 +540,104 @@ o S2L_SUB_LSP_MARKER_BEGIN and S2L_SUB_LSP_MARKER_END Object types: +---------------+---------------------------+-----------------+ | C-Type value | Description | Reference | +---------------+---------------------------+-----------------+ | TBA by IANA | S2L_SUB_LSP_MARKER_BEGIN | This document | +---------------+---------------------------+-----------------+ | TBA by IANA | S2L_SUB_LSP_MARKER_END | This document | +---------------+---------------------------+-----------------+ -8. Acknowledgments +7. Security Considerations - The authors would like to thank Loa Andersson, Sriganesh Kini, Curtis - Villamizar, Dimitri Papadimitriou and Nobo Akiya for reviewing this - document. The authors would also like to thank Ling Zeng for - implementing mechanisms defined in this document. + This document defines RSVP-TE signaling extensions to allow an + ingress node of a P2MP-TE LSP to request the re-evaluation of the + entire LSP tree, and for a mid-point LSR to notify the ingress node + of the existence of a preferable tree by sending a PathErr. As per + [RFC4736], in the case of a P2MP-TE LSP S2L sub-LSP spanning multiple + domains, it may be desirable for a mid-point LSR to modify the RSVP + PathErr message defined in this document to preserve confidentiality + across domains. Furthermore, an ingress node may decide to ignore + this PathErr message coming from a mid-point LSR residing in another + domain. Similarly, a mid-point LSR may decide to ignore the P2MP-TE + tree re-evaluation request originating from another ingress domain. -9. References + This document also defines markers to indicate beginning and end of + an S2L sub-LSP descriptor list when combining large number of S2L + sub-LSPs in an RSVP message and the message needs to be fragmented. + The introduction of these markers, by themselves, introduce no + additional information to signaling. For a general discussions on + MPLS and GMPLS related security issues, see the MPLS/GMPLS security + framework [RFC5920]. -9.1. Normative References +8. References + +8.1. Normative References + + [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate + Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2205] Braden, R., Ed., Zhang, L., Berson, S., Herzog, S., and S. Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1 Functional Specification", RFC 2205, September 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. + [RFC4736] Vasseur, JP., Ikejiri, Y. and Zhang, R, "Reoptimization of + Multiprotocol Label Switching (MPLS) Traffic Engineering + (TE) Loosely Routed Label Switched Path (LSP)", RFC 4736, + November 2006. + [RFC4875] Aggarwal, R., Papadimitriou, D., and S. Yasukawa, "Extensions to Resource Reservation Protocol Traffic Engineering (RSVP-TE) for Point-to-Multipoint TE Label Switched Paths (LSPs)", RFC 4875, May 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. -9.2. Informative References - - [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate - Requirement Levels", BCP 14, RFC 2119, March 1997. - - [RFC4736] Vasseur, JP., Ikejiri, Y. and Zhang, R, "Reoptimization of - Multiprotocol Label Switching (MPLS) Traffic Engineering - (TE) Loosely Routed Label Switched Path (LSP)", RFC 4736, - November 2006. +8.2. Informative References [RFC5440] Vasseur, JP., Ed., and JL. Le Roux, Ed., "Path Computation Element (PCE) Communication Protocol (PCEP)", RFC 5440, March 2009. [RFC5920] Fang, L., "Security Framework for MPLS and GMPLS Networks", RFC 5920, July 2010. +Acknowledgments + + The authors would like to thank Loa Andersson, Sriganesh Kini, Curtis + Villamizar, Dimitri Papadimitriou and Nobo Akiya for reviewing this + document. The authors would also like to thank Ling Zeng for + implementing mechanisms defined in this document. + Author's Addresses Tarek Saad (editor) Cisco Systems - Email: tsaad@cisco.com + EMail: tsaad@cisco.com Rakesh Gandhi (editor) Cisco Systems - Email: rgandhi@cisco.com + EMail: rgandhi@cisco.com Zafar Ali Cisco Systems - Email: zali@cisco.com + EMail: zali@cisco.com Robert H. Venator Defense Information Systems Agency - Email: robert.h.venator.civ@mail.mil + EMail: robert.h.venator.civ@mail.mil Yuji Kamite NTT Communications Corporation - Email: y.kamite@ntt.com + EMail: y.kamite@ntt.com