Network Working Group Tomohiro Otani Internet Draft KDDI Intended status: Informational Kenichi Ogaki KDDI R&D Labs Diego Caviglia Ericsson Fatai Zhang Huawei Expires: January 2011 July 6, 2010 Requirements for GMPLS applications of PCE Document: draft-ietf-pce-gmpls-aps-req-02.txt Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and 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. This Internet-Draft will expire on January 5, 2011. Abstract The initial effort of PCE WG is specifically focused on MPLS (Multi- protocol label switching). As a next step, this draft describes functional requirements for GMPLS (Generalized MPLS) application of PCE (Path computation element). T. Otani et al. Expires January 2011 [Page 1] Internet Draft Reqs for GMPLS apps of PCE July 2010 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 [RFC2119]. Table of Contents 1. Introduction.................................................2 2. Terminology..................................................3 3. GMPLS applications of PCE....................................3 3.1. GMPLS network model.....................................3 3.2. Path computation in GMPLS network.......................3 3.3. Unnumbered Interface....................................5 3.4. Asymmetric Bandwidth Path Computation...................6 4. Requirement for GMPLS application of PCE.....................6 4.1. PCE requirements........................................6 4.2. PCC requirements........................................7 4.3. GMPLS PCE Management....................................7 5. Security consideration.......................................7 6. IANA Considerations..........................................7 7. Acknowledgement..............................................7 8. References...................................................7 9. Authors' Addresses...........................................9 1. Introduction The initial effort of PCE WG is focused on solving the path computation problem over different domains in MPLS networks. As the same case with MPLS, service providers (SPs) have also come up with requirements for path computation in GMPLS networks such as photonics, TDM-based or Ethernet-based networks as well. [PCE-ARCH] and [PCECP-REQ] discuss the framework and requirements for PCE on both packet MPLS networks and (non-packet switch capable) GMPLS networks. This document complements these documents by providing some consideration of GMPLS applications in the intra- domain and inter-domain networking environments and indicating a set of requirements for the extended definition of series of PCE related protocols. Constraint based shortest path first (CSPF) computation within a domain or over domains for signaling GMPLS Label Switched Paths (LSPs) is more stringent than that of MPLS LSPs [MPLS-AS], because the additional constraints, e.g., interface switching capability, link encoding, link protection capability and so forth need to be considered to establish GMPLS LSPs [CSPF]. GMPLS signaling protocol [RFC3471, RFC3473] is designed taking into account bi-directionality, switching type, encoding type, SRLG, and protection attributes of the T. Otani et al. Expires January 2011 [Page 2] Internet Draft Reqs for GMPLS apps of PCE July 2010 TE links spanned by the path, as well as LSP encoding and switching type for the end points, appropriately. This document provides the investigated results of GMPLS applications of PCE for the support of GMPLS path computation. This document also provides requirements for GMPLS applications of PCE in the GMPLS intra-domain and inter-domain environments. 2. Terminology 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]. 3. GMPLS applications of PCE 3.1. GMPLS network model Figure 1 depicts a typical network, consisting of several GMPLS domains, assumed in this document. D1, D2, D3 and D4 have multiple GMPLS inter-domain connections, and D5 has only one GMPLS inter- domain connection. These domains follow the definition in [RFC4726]. +---------+ +---------|GMPLS D2|----------+ | +----+----+ | +----+----+ | +----+----+ +---------+ |GMPLS D1| | |GMPLS D4|---|GMPLS D5| +----+----+ | +----+----+ +---------+ | +----+----+ | +---------|GMPLS D3|----------+ +---------+ Figure 1: GMPLS Inter-domain network model. Each domain is configured using various switching and link technologies defined in [Arch] and an end-to-end route needs to respect TE link attributes like switching capability, encoding type, etc., making the problem a bit different from the case of classical (packet) MPLS. In order to route from one GMPLS domain to another GMPLS domain appropriately, each domain manages traffic engineering database (TED) by PCE, and exchanges or provides route information of paths, while concealing its internal topology information. 3.2. Path computation in GMPLS network [CSPF] describes consideration of GMPLS TE attributes during path computation. T. Otani et al. Expires January 2011 [Page 3] Internet Draft Reqs for GMPLS apps of PCE July 2010 Ingress Transit Egress +-----+ link1-2 +-----+ link2-3 +-----+ link3-4 +-----+ |Node1|------------>|Node2|------------>|Node3|------------>|Node4| | |<------------| |<------------| |<------------| | +-----+ link2-1 +-----+ link3-2 +-----+ link4-3 +-----+ Figure 2: Path computation in GMPLS networks. For the simplicity in consideration, the below basic assumptions are made when the LSP is created. (1) Switching capabilities of outgoing links from the ingress and egress nodes (link1-2 and link4-3 in Figure 2) must be consistent with each other. (2) Switching capabilities 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. [CSPF] indicates the possible table of switching capability, encoding type and bandwidth at the ingress link, transiting links and the egress link which need to be satisfied with the created LSP. The non-packet GMPLS networks (e.g., TDM networks) are usually responsible for transmitting data for the client layer. These GMPLS networks can provide different types of connections for customer services based on different service bandwidth requests. The applications and the corresponding additional requirements for applying PCE in non-packet networks, for example, GMPLS-based TDM networks, are described in Figure 3. In order to simplify the description, this document just discusses the scenario in SDH networks as an example. The scenarios in SONET or G.709 ODUk layer networks are similar. T. Otani et al. Expires January 2011 [Page 4] Internet Draft Reqs for GMPLS apps of PCE July 2010 N1 N2 +-----+ +------+ +------+ | |-------| |--------------| | +-------+ +-----+ | |---| | | | | A1 +------+ | +------+ | | | | | +-------+ | | | PCE | | | | +------+ | | | | | | | |-----| | | +------+ | | | N5 | | | | | +------+ +------+ | | | | +-----+ | |--------------| |--------| | +------+ +------+ +-----+ N3 N4 A2 Figure 3: A simple SDH network Figure 3 shows a simple network topology, where N1, N2, N3, N4, and N5 are all SDH switches. Assume that one Ethernet service with 100M bandwidth is required from A1 to A2 over this network. The client Ethernet service could be provided by a VC4 connection from N1 to N4, and it could also be provided by three concatenated VC3 connections (Contiguous or Virtual concatenation) from N1 to N4. The type of connection(s) (one VC4 or three concatenated VC3) that is required needs to be specified by PCC (e.g., N1 or NMS), but could also be determined by PCE automatically based on policy [RFC5394]. Therefore, the signal type, the type of the concatenation and the number of the concatenation should also be considered during path computation for PCE. 3.3. Unnumbered Interface GMPLS support unnumbered interface ID that is defined in [RFC 3477], which means that the endpoints of the path may be unnumbered. It should also be possible to request a Path between a numbered link and an unnumbered link, or a P2MP path between different types of endpoints. Therefore, the PCC should be capable of indicating the unnumbered interface ID of the endpoints in the PCReq message. T. Otani et al. Expires January 2011 [Page 5] Internet Draft Reqs for GMPLS apps of PCE July 2010 3.4. Asymmetric Bandwidth Path Computation As per [RFC 5467], GMPLS signaling can be used for setting up an asymmetric bandwidth bidirectional LSP. If a PCE is responsible for the path computation, the PCE should be capable of computing a path for the bidirectional LSP with asymmetric bandwidth. It means that the PCC should be able to indicate the asymmetric bandwidth requirements in forward and reverse directions in the PCReq message. 4. Requirement for GMPLS application of PCE In this section, we describe requirements for GMPLS applications of PCE in order to establish GMPLS LSP. 4.1. PCE requirements As for path computation in GMPLS networks as discussed in section 3, the PCE needs to consider the GMPLS TE attributes appropriately according to tables in [CSPF] once a PCC or another PCE requests a path computation. Indeed, the path calculation request message from the PCC or the PCE needs to contain the information specifying appropriate attributes. Additional attributes to those already defined in [PCECP] are as follows. (1) Switching capability: PSC1-4, L2SC, DCSC [DCSC-Ext], 802_1 PBB-TE [GMPLS-PBB-TE], TDM, LSC, FSC (2) Encoding type: as defined in [RFC4202], [RFC4203], e.g., Ethernet, SONET/SDH, Lambda, etc. (3) Signal Type: Indicates the type of elementary signal that constitutes the requested LSP. A lot of signal types with different granularity have been defined in SONET/SDH and G.709 ODUk, such as VC11, VC12, VC2, VC3 and VC4 in SDH, and ODU1, ODU2 and ODU3 in G.709 ODUk. See [RFC4606] and [RFC4328]. (4) Concatenation Type: In SDH/SONET and G.709 ODUk networks, two kinds of concatenation modes are defined: contiguous concatenation which requires co-route for each member signal and requires all the interfaces along the path to support this capability, and virtual concatenation which allows diverse routes for the member signals and only requires the ingress and egress interfaces to support this capability. Note that for the virtual concatenation, it also may specify co-routed or separated-routed. See [RFC4606] and [RFC4328] about Concatenation information. (5) Concatenation Number: Indicates the number of signals that are requested to be contiguously or virtually concatenated. Also see [RFC4606] and [RFC4328]. T. Otani et al. Expires January 2011 [Page 6] Internet Draft Reqs for GMPLS apps of PCE July 2010 (6) Wavelength Label: as defined in [Lambda-label]. (7) e2e Path protection type: as defined in [RFC4872], e.g., 1+1 protection, 1:1 protection, (pre-planned) rerouting, etc. (8) Administrative group: as defined in [RFC3630]. (9) Link Protection type: as defined in [RFC4203]. (10)Support for unnumbered interfaces: as defined in [RFC3477]. (11)Support for asymmetric bandwidth request: as defined in [RFC 5467]. 4.2. PCC requirements As described above, a PCC needs to support to initiate path computation request specifying abovementioned attributes. Afterwards, GMPLS signaling will be invoked according to the responded messages from the PCE. 4.3. GMPLS PCE Management PCE related Management Information Bases need to consider extensions to be satisfied with requirements for GMPLS applications. For extensions, [GMPLS-TEMIB] are defined to manage TE database and may be referred to accommodate GMPLS TE attributes in the PCE. 5. Security consideration PCE extensions to support GMPLS should be considered under the same security as current work. This extension will not change the underlying security issues. 6. IANA Considerations This document has no actions for IANA. 7. Acknowledgement The author would like to express the thanks to Shuichi Okamoto for his comments. 8. References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. T. Otani et al. Expires January 2011 [Page 7] Internet Draft Reqs for GMPLS apps of PCE July 2010 [PCE-ARCH] A. Farrel, et al, "A Path Computation Element (PCE)-Based Architecture", RFC4655, Aug., 2006. [PCECP-REQ] J. Ash, et al, "Path computation element (PCE) communication protocol generic requirements", RFC4657, Sept., 2007. [MPLS-AS] R. Zhan, et al, "MPLS Inter-Autonomous System (AS) Traffic Engineering (TE) Requirements", RFC4216, November 2005. [CSPF] T. Otani, et al, "Considering Generalized Multiprotocol Label Switching Traffic Engineering Attributes During Path Computation", draft-otani-ccamp-gmpls-cspf-constraints- 07.txt, Feb., 2008. [RFC3471] Berger, L., "Generalized Multi-Protocol Label Switching (MPLS) Signaling Functional Description", RFC 3471, January 2003. [RFC3473] Berger, L., "Generalized Multi-Protocol Label Switching (MPLS) Signaling - Resource ReserVation Protocol Traffic Engineering (RSVP-TE) Extensions", RFC 3473, January 2003. [RFC4726] A. Farrel, et al, "A framework for inter-domain MPLS traffic engineering", RFC4726, November 2006. [Arch] E. Mannie, et al, "Generalized Multi-Protocol Label Switching Architecture", RFC3945, October, 2004. [PCECP] J.P. Vasseur, et al, "Path Computation Element (PCE) Communication Protocol (PCEP)", RFC5440, March 2009. [RFC4202] K. Kompella, and Y. Rekhter, "Routing Extensions in Support of Generalized Multi-Protocol Label Switching", RFC4202, Oct. 2005. [RFC4203] K. Kompella, and Y. Rekhter, "OSPF Extensions in Support of Generalized Multi-Protocol Label Switching", RFC4203, Oct. 2005. [RFC4872] J.P. Lang, Ed., "RSVP-TE Extensions in Support of End-to-End Generalized Multi-Protocol Label Switching (GMPLS) Recovery", RFC4872, May 2007. [GMPLS-TEMIB] T. Nadeau and A. Farrel, Ed., "Generalized Multiprotocol Label Switching (GMPLS) Traffic Engineering Management Information Base", RFC4802, Feb. 2007. [RFC3630] D. Katz et al., "Traffic Engineering (TE) Extensions to OSPF Version 2", RFC3630, September 2003. T. Otani et al. Expires January 2011 [Page 8] Internet Draft Reqs for GMPLS apps of PCE July 2010 [Lambda-label] T. Otani, Ed., "Generalized Labels for G.694 Lambda- Switching Capable Label Switching Routers", draft-ietf- ccamp-gmpls-g-694-lambda-labels, in progress. [RFC5394] I. Bryskin et al., " Policy-Enabled Path Computation Framework", RFC5394, December 2008. [RFC4606] E. Mannie and D. Papadimitriou, "Generalized Multi-Protocol Label Switching (GMPLS) Extensions for Synchronous Optical Network (SONET) and Synchronous Digital Hierarchy (SDH) Control", RFC4606, August 2006. [RFC4328] D. Papadimitriou, Ed., "Generalized Multi-Protocol Label Switching (GMPLS) Signaling Extensions for G.709 Optical Transport Networks Control", RFC4328, January 2006. [DCSC-Ext] Lou Berger, et al.,"Generalized MPLS (GMPLS) Data Channel Switching Capable (DCSC) and Channel Set Label Extensions", in progress. [GMPLS-PBB-TE] Don Fedyk, et al., "Generalized Multiprotocol Label Switching (GMPLS) control of Ethernet PBB-TE", in progress. 9. Authors' Addresses Tomohiro Otani KDDI Corporation 2-3-2 Nishi-shinjuku Shinjuku-ku, Tokyo 163-8003 Japan Phone: +81-3-3347-6006 Email: tm-otani@kddi.com 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 Diego Caviglia Ericsson 16153 Genova Cornigliano, ITALY Phone: +390106003736 Email: diego.caviglia@ericsson.com Fatai Zhang Huawei Technologies Co., Ltd. F3-5-B R&D Center, Huawei Base, T. Otani et al. 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