IETF Internet Draft Tomohiro Otani Proposed status: Standards Track Kenichi Ogaki Expires: October 2006 KDDI R&D Labs Arthi Ayyangar Kireeti Kompella Juniper Networks Rajiv Papneja Isocore April 2006 GMPLS constraints consideration for CSPF path computation Document: draft-otani-ccamp-gmpls-cspf-constraints-03.txt Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of 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." 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. Copyright Notice Copyright (C) The Internet Society (2006). All Rights Reserved. Abstract This draft provides the guideline to consider generalized multi- protocol label switching (GMPLS) traffic-engineering (TE) attributes for constraint-based shortest path first (CSPF) path computation at a source node in a GMPLS network environment. This draft summarizes most possible cases of GMPLS constraint TE attributes at an ingress link, transit links and an egress link to establish a GMPLS label switched path (LSP) appropriately. T. Otani et al. Expires October 2006 1 Internet Drafts draft-otani-ccamp-gmpls-cspf-constraints-03.txt April 2006 Table of Contents Status of this Memo................................................1 Abstract...........................................................1 1. Introduction....................................................3 2. Conventions used in this document...............................3 3. Assumed network model...........................................3 4. CSPF consideration..............................................5 5. Security consideration..........................................9 6. Intellectual property considerations............................9 7. Informative references.........................................10 Author's Addresses................................................10 Document expiration...............................................11 Copyright statement...............................................11 T. Otani et al. Expires October 2006 2 Internet Drafts draft-otani-ccamp-gmpls-cspf-constraints-03.txt April 2006 1. Introduction A GMPLS network is, in general, controlled and managed by various GMPLS specific TE attributes underlying used physical/logical technologies of links as well as nodes [Arch]. To establish a GMPLS LSP appropriately in such a networking environment, these TE attributes (advertised from others or belonging to themselves) must be dealt correctly when CSPF path computation under a certain GMPLS constraint is conducted [GMPLS-routing], and GMPLS LSP must be created following a feasible route. However, since these constraints vary and are differently understood among such an integrated environment (especially between optical transport point of view and packet transport point of view), this draft proposes and provides a kind of guideline to facilitate GMPLS CSPF path computation, summarizing most possible cases of GMPLS constraint attributes at an ingress link, transit links and an egress link to establish a GMPLS LSP appropriately. 2. 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]. 3. Assumed network model 3.1 GMPLS TE attributes consideration for CSPF calculation For CSPF path computation to establish GMPLS LSPs correctly, various GMPLS attributes [GMPLS-routing, GMPLS-OSPF] of links as well as nodes, as indicated below, must be taken into account in a GMPLS network environment in addition to TE attributes of packet based network [OSPF-TE]. (1) Encoding-type: SONET/SDH, Lambda, Ethernet, etc. (2) Switching capability: TDM, Lambda, Fiber, etc. (3) Bandwidth: OC-192, OC-48, GbE, 10GbE, etc. These logical attributes have a very tight relationship with underlying physical technologies such as SONET/SDH, optical transport network (OTN) or Ethernet in terms of links, and all-optical switches, SONET/SDH-basis digital cross connect or electrical-basis optical switches in terms of nodes. Therefore, the GMPLS LSPs must satisfy logical constrains as well as corresponding physical constraints. These constraints are sometimes differently understood among different layers, and a logically computed GMPLS LSP may violate the physical constraints, therefore, a consistent guideline to solve this issue should be formulated. T. Otani et al. Expires October 2006 3 Internet Drafts draft-otani-ccamp-gmpls-cspf-constraints-03.txt April 2006 3.2 Considered network model Figure 1 depicts a typical GMPLS network, consisting of an ingress link, a transit link as well as an egress link, to investigate a consistent guideline for GMPLS CSPF path computation. Each link outgoing or incoming at each interface has its own switching capability, encoding-type and bandwidth. The consideration here is based on a single domain GMPLS network, but the analysis may be able to be applicable to an inter-domain GMPLS network. Ingress Transit Egress +-----+ link1-2 +-----+ link2-3 +-----+ link3-4 +-----+ |Node1|------------>|Node2|------------>|Node3|------------>|Node4| | |<------------| |<------------| |<------------| | +-----+ link2-1 +-----+ link3-2 +-----+ link4-3 +-----+ Figure 1: GMPLS network model For the simplicity of the analysis in CSPF consideration, the below basic assumptions are made when the LSP is created. (1) Switching capabilities (SC) of outgoing links from the ingress and egress nodes (link1-2 and link4-3 in Figure 1) must be consistent with each other. (2) SC of all transit links including incoming links to the ingress and egress nodes (link2-1 and link3-4) should be consistent with switching type of a LSP to be created. (3) Encoding-types of all transit links should be consistent with encoding type of a LSP to be created. GMPLS network is a multi-layer network, which is composed of multiple nodes with different switching capability and encoding type interfaces. Therefore, a hierarchical structure may be considered in CSPF path computation. In such a case, the combination between the switching type and encoding type of a desired LSP, and those of all transit links described as the table in following section may be acceptable. One of advertised multiple interface switching capability descriptors for the same link [GMPLS-Routing] should be also appropriately chosen as the attribute for the link. Bandwidth of each TE link is maximum LSP bandwidth in interface switching capability descriptor at the priority for a desired LSP [GMPLS-OSPF], and encoding-types of incoming and outgoing links on the same interface (for example, link1-2 and link2-1) should be consistent with each other. T. Otani et al. Expires October 2006 4 Internet Drafts draft-otani-ccamp-gmpls-cspf-constraints-03.txt April 2006 In case that the network is comprised of numbered links and unnumbered links [RFC3477], an ingress node, who is able to support numbered links and unnumbered links may choose both links being part of the same desired LSP. 4. CSPF consideration In this section, we consider GMPLS constraints to be satisfied in different cases of link attributes. When a LSP indicated in below tables is created, the CSPF path computation must choose the route so as to satisfy switching capability, encoding-type and bandwidth at the ingress link, transiting links and the egress link indicated in columns next to the created LSP, considering underlying physical constraints. Here, almost cases of GMPLS CSPF consideration are summarized in this document, however, some cases will be added in a future version. (1) TDM-switch capable Table 1: Desired GMPLS attributes in the case of TDM-SC +-------------+---------+------------+---------+------------------+ |LSP attribute|Ingress |Transit |Egress |Remarks | +---+---------+---------+------------+---------+------------------+ | | |TDM | |TDM | | | | +---------+ +---------+ | |SC*|TDM |L2SC |TDM |L2SC | | | | +---------+ +---------+ | | | |PSC | |PSC | | +---+---------+---------+------------+---------+ | | |SONET/SDH|SONET/SDH|SONET/SDH |SONET/SDH|Specified in G.691| | +---------+---------+------------+---------+ | |Enc|Ethernet |Ethernet |SONET/SDH |Ethernet |Specified in IEEE | | | | |or Ethernet | | | | +---------+---------+------------+---------+ | | |OTN* |OTN |OTN |OTN | | +---+---------+---------+------------+---------+ | |BW |X |<=bw |<=bw |<=bw | | +---+---------+---------+------------+---------+------------------+ *SC in LSP means a desired switching type of LSP. *OTN interfaces are equivalent to digital wrapper technology in this draft. In this case, since the interface with TDM SC supports sub-rate switching, BW X can be equal to or less than bw of ingress, transit and egress links, and must be larger than the minimum LSP bandwidth T. Otani et al. Expires October 2006 5 Internet Drafts draft-otani-ccamp-gmpls-cspf-constraints-03.txt April 2006 in the interface switching capability descriptor. A sub-rate switching is unsuited for a hierarchical LSP, because the lower-layer link usually has larger granular bandwidth than that layer except PSC-x, for example a TDM LSP with the desired bandwidth of OC-12 should not use a lambda switching capable link with the bandwidth of OC-48 as a transit link. In such a case, a lambda LSP as a forwarding adjacency (FA) LSP is created on the lower (lambda) layer in advance, then the FA-LSP [LSP-HIER] may be advertised as a TDM SC link. (2) Lambda switch capable (LSC) Table 2.1: Desired GMPLS attributes in the case of LSC without lambda encoding +-------------+---------+------------+---------+------------------+ |LSP attribute|Ingress |Transit |Egress |Remarks | +---+---------+---------+------------+---------+------------------+ | | |LSC | |LSC | | | | +---------+ +---------+ | |SC |LSC |TDM |LSC |TDM | | | | +---------+ +---------+ | | | |L2SC | |L2SC | | | | +---------+ +---------+ | | | |PSC | |PSC | | +---+---------+---------+------------+---------+[GMPLS-Routing] | | |SONET/SDH|SONET/SDH|SONET/SDH |SONET/SDH|section 3.6, 3.9 | | +---------+---------+------------+---------+Specified in G.691| |Enc|Ethernet |Ethernet |Ethernet |Ethernet |Specified in IEEE | | +---------+---------+------------+---------+ | | |OTN |OTN |OTN |OTN |Specified in G.709| |---+---------+---------+------------+---------+------------------+ |BW |X |=bw |=bw |=bw | | +---+---------+---------+------------+---------+------------------+ The interface with LSC supports only optical signal switching, BW X must be equal to bw so as to match bit-rate and its framing. T. Otani et al. Expires October 2006 6 Internet Drafts draft-otani-ccamp-gmpls-cspf-constraints-03.txt April 2006 Table 2.2: Desired GMPLS attributes in the case of LSC with lambda encoding +-------------+---------+------------+---------+------------------+ |LSP attribute|Ingress |Transit |Egress |Remarks | +---+---------+---------+------------+---------+------------------+ | | |LSC | |LSC | | | | +---------+ +---------+ | |SC |LSC |TDM |LSC |TDM | | | | +---------+ +---------+ | | | |L2SC | |L2SC | | | | +---------+ +---------+ | | | |PSC | |PSC | | +---+---------+---------+------------+---------+ | | |lambda | | | |[GMPLS-Routing] | | +---------+ | | |section 3.7, 3.10 | |Enc|SONET/SDH| | | |Specified in G.691| | +---------+lambda |lambda |lambda | | | |Ethernet | | | |Specified in IEEE | | +---------+ | | | | | |OTN | | | |Specified in G.709| +---+---------+---------+------------+---------+ | |BW |X |<=bw |<=bw |<=bw | | +---+---------+---------+------------+---------+------------------+ In the case of an interface with a lambda encoding-type and a transparent to bit-rate and framing, BW X must be equal to or less than bw. (3) Fiber switch capable (FSC) T. Otani et al. Expires October 2006 7 Internet Drafts draft-otani-ccamp-gmpls-cspf-constraints-03.txt April 2006 Table 3: Desired GMPLS attributes in the case of FSC +---+---------+---------+------------+---------+------------------+ |LSP attribute|Ingress |Transit |Egress |Remarks | +---+---------+---------+------------+---------+------------------+ | | |FSC | |FSC | | | | +---------+ +---------+ | | | |LSC | |LSC | | | | +---------+ +---------+ | |SC |FSC |TDM |FSC |TDM | | | | +---------+ +---------+ | | | |L2SC | |L2SC | | | | +---------+ +---------+ | | | |PSC | |PSC | | +---+---------+---------+------------+---------+[GMPLS-Routing] | | |fiber |fiber |fiber |fiber |section 3.8 | | +---------+---------+------------+---------+ | | |lambda |lambda |lambda |lambda |section 3.7, 3.10 | | | |or fiber |or fiber |or fiber | | | +---------+---------+------------+---------+ | |Enc| |SONET/SDH|SONET/SDH |SONET/SDH|section 3.6, 3.9 | | |SONET/SDH|, lambda |, lambda |, lambda |Specified in G.691| | | |or fiber |or fiber |or fiber | | | +---------+---------+------------+---------+ | | | |Ethernet,|Ethernet, |Ethernet,|Specified in IEEE | | |Ethernet |lambda |lambda |lambda | | | | |or fiber |or fiber |or fiber | | | +---------+---------+------------+---------+ | | | |OTN, |OTN, |OTN, |Specified in G.709| | |OTN |lambda |lambda |lambda | | | | |or fiber |or fiber |or fiber | | +---+---------+---------+------------+---------+ | |BW |X |<=bw |<=bw |<=bw | | +---+---------+---------+------------+---------+------------------+ Although the interface with FSC can switch the entire contents to another interface, this interface should be used for only optical wavelength or waveband switching. (4) Layer 2 switch capable (L2SC) The guideline for the calculation must be created after the definition and discussion L2SW are settled down. (5) Packet switch capable (PSC) T. Otani et al. Expires October 2006 8 Internet Drafts draft-otani-ccamp-gmpls-cspf-constraints-03.txt April 2006 Table 4: Desired GMPLS attributes in the case of PSC +-------------+---------+------------+---------+------------------+ |LSP attribute|Ingress |Transit |Egress |Remarks | +---+---------+---------+------------+---------+------------------+ |SC |PSC |PSC |PSC |PSC | | +---+---------+---------+------------+---------+ | |Enc|Packet |Packet |Packet |Packet | | +---+---------+---------+------------+---------+ | |BW |X |<=bw |<=bw |<=bw | | +---+---------+---------+------------+---------+------------------+ Since the interface with PSC supports only packet-by-packet switching, BW X must be equal to or less than bw, and must be larger than the minimum LSP bandwidth. These GMPLS constraints must be considered for computing CSPF and creating GMPLS LSPs. 6. Security consideration GMPLS CSPF consideration will not change the underlying security issues. 7. Intellectual property considerations The IETF takes no position regarding the validity or scope of any intellectual property or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; neither does it represent that it has made any effort to identify any such rights. Information on the IETF's procedures with respect to rights in standards-track and standards-related documentation can be found in BCP-11. Copies of claims of rights made available for publication and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF Secretariat. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights which may cover technology that may be required to practice this standard. Please address the information to the IETF Executive Director. T. Otani et al. Expires October 2006 9 Internet Drafts draft-otani-ccamp-gmpls-cspf-constraints-03.txt April 2006 8. Informative references [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [Arch] E. Mannie, "Generalized Multi-Protocol Label Switching Architecture", RFC3945, October, 2004. [GMPLS-Routing] K. Kompella and Y. Rekhter, "Routing Extensions in Support of Generalized Multi-Protocol Label Switching", RFC4202, October 2005. [GMPLS-OSPF] K. Kompella and Y. Rekhter, "OSPF Extensions in Support of Generalized Multi-Protocol Label Switching", RFC4203, October 2005. [OSPF-TE] Katz, D., et al, "Traffic Engineering (TE) Extensions to OSPF Version 2", RFC3630, September 2003. [RFC3477] K. Kompella and Y. Rekhter, "Signalling Unnumberd Links in Resource ReSerVation Protocol - Traffic Engineering (RSVP-TE)", RFC3477, January 2003. [LSP-HIER] K.Komepella and Y. Rekhter, "Label Switched Paths (LSP) Hierarchy with Generalized Multi-Protocol Label Switching (GMPLS) Traffic Engineering (TE)", RFC4204, October 2005. Author's Addresses Tomohiro Otani KDDI R&D Laboratories, Inc. 2-1-15 Ohara Fujimino-shi Saitama, 356-8502 Japan Phone: +81-49-278-7357 Email: otani@kddilabs.jp Kenichi Ogaki KDDI R&D Laboratories, Inc. 2-1-15 Ohara Fujimino-shi Saitama, 356-8502 Japan Phone: +81-49-278-7897 Email: ogaki@kddilabs.jp Arthi Ayyangar Juniper Networks 1194 N. Mathilda Ave. Sunnyvale, CA 94089 US Email: arthi@juniper.net Rajiv Papneja Isocore 12359 Sunrise Valley Drive Suite 100, Reston, VA 20191 US Email: rpapneja@isocore.com T. Otani et al. Expires October 2006 10 Internet Drafts draft-otani-ccamp-gmpls-cspf-constraints-03.txt April 2006 Kireeti Kompella Juniper Networks 1194 N. Mathilda Ave. Sunnyvale, CA 94089 US Email: kireeti@juniper.net Document expiration This document will be expired in April 2006, unless it is updated. Copyright statement Copyright (C) The Internet Society (2006). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. T. Otani et al. Expires October 2006 11