Network Working Group Wataru Imajuku Internet Draft NTT draft-imajuku-ml-routing-00.txt Eiji Oki Expiration Date: August 2002 NTT Kohei Shiomoto NTT Satoru Okamoto NTT February 2002 Multi-layer routing using multiple-layer switch capable LSRs draft-imajuku-ml-routing-00.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 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 (2002). All Rights Reserved. Abstract The integration of multi-layer switching capabilities within one box, such as the packet-switch capability (PSC) and the lambda- switch capability (LSC) under MPLS/Generalized-MPLS control mecanism, paves the way for realizing the network resouce optimization with multi-layer routing consideration. This document clarifies the model of the GMPLS-controlled integrated PSC/LSC label switch router (LSR) and discuss the requirement of routing extensions which enable to realize the optimized multi-layer traffic engineering. Imajuku [Page 1] Internet Draft draft-imajuku-ml-routing-00.txt 22 February 2002 1. Introduction Generalized-MPLS makes easier to realize seamless integration of IP network and legacy SDH/SONET or Photonic networks. Especially, integration of the packet switching capability and the photonic switching technology under unified GMPLS control plane brings major impact on enhancing forwarding capacity of IP network [Shimano01]. One of the other driving force to construct unified GMPLS control plane is the desire to implement multi-layer routing capability which enables effective network resource utilization of both IP- layer and SDH/SONET or Photonic-layer in the next generation large capacity IP+Photonic network [Oki02]. In such network, each LSR would contain multiple-type switching capabilities such as PSC and Time-Division-Multiplexing capable (or SDH/SONET XC) (TDM), PSC and Lambda switch capable (LSC), LSC and Fiber switch capable (FSC), etc. These LSRs with the integrated switch capabilities shall be required to have resource information of not only each LSR's link states or network topology but also other LSR's, since circuit switch capable such as TDMs, LSCs, FSCs require rigid resource reservation rather than PSCs. The implementation of such functionality enables seamless multi-layer optimized route calculation such that the conventional label switched path (LSP) call setup automatically triggers new optical label switched path (OLSP) setup with the consideration of unused resources of inner interfaces between PSC functional block and LSC functional block in the OLSP destination node. If the resouce of inner interface between PSC and LSC in the OLSP destination node is not able to reserve, second-new OLSP setup can be triggered which bounds for an intermediate LSR and the LSP-call can be alternatively accomodated to the second OLSP and hops to other existing OLSP bounds for the destination node of the LSP-call. This draft proposes several extension to link state information of OSPF/ISIS disseminated to all LSRs in the routing area to realize multi-layer routing. The extension of link state information includes the basic concept of the interface switching capability descriptor as discussed in [GMPLS-ROURING] and [GMPLS-OSPF]. The content of this document comprises as follows. First, modelize the GMPLS based LSR with multi-layer switching capabilities. Second, discuss the aspect of multi-layer routing and specification of the link state advertisements (LSAs). Last, discuss the interaction with FA-LSP and it's LSAs which shall be disseminated to other LSRs in response to the creation of LSPs. Imajuku [Page 2] Internet Draft draft-imajuku-ml-routing-00.txt 22 February 2002 2. The node model of GMPLS based LSRs with lambda switching capability This section clarifies the model of switching capable of GMPLS based LSRs to make clear the requirements for multi-layer routing under the unified GMPLS-control plane. 2.1 LSC-LSR The first model is LSR with LSC only. The LSC handles just single OLSP to switch over from fiber to fiber. This type of LSR does not have packet-level switching capability. Therefore, other LSRs in the same routing area (or domain) shall recognize that the LSR does not have functionality of IP packet routing and LSP switching. Requirement: When there is no unused input and output port in the LSR, the LSR shall be identified as the LSC router which has no OLSP forwarding capability. _______ | | __\ /|___| |___|\ / | |___| |___| | Fiber #1 ========| |___| LSC |___| |======== | |___| |___| | \| | | |/ | | . . . . __\ /|___| |___|\ / | |___| |___| | Fiber #N ========| |___| |___| |======== | |___| |___| | \| | | |/ |_______| If the LSC-LSR does not have wavelength conversion capability (in the most case of the all-optical networks), the information that which wavelength channel can be reserved in a fiber link plays the Imajuku [Page 3] Internet Draft draft-imajuku-ml-routing-00.txt 22 February 2002 important role for the route selection of the OLSP setup. Thus, LSC- LSR shall also recognize and advertise the status of the unused wavelength channel number as described in the document [OKI-OLI]. In the process of the network topology construction from fiber link state data, each fiber link connected to LSRs may be identified as a TE-link between neighbor LSRs. Component links, which may correspond to wavelength channels or LSC switch ports, in one or multiple fibers are bundled into a TE-link, where every wavelength information is aggregated [LINK-BUNDLE]. 2.2 LSR with PSC+LSC The second model is LSR with PSC+LSC. The PSC is connected to the LSC with internal interfaces between the PSC function block and the LSC function block. The LSC handles just single OLSP to switch over from fiber to fiber. This type of LSR has the switching capability of both conventional LSPs and OLSPs. Therefore, other LSRs in the same routing area (or domain) shall recognize that the LSR has the forwarding capability both IP packets and OLSPs. Requirements: If all switch ports of the LSC function block are occupied, an OLSP setup call transferring or terminating at the LSR shall be rejected. In such case, other LSRs in the same routing area (or domain) shall recognize that the PSC+LSC router which has no reservable LSC capability. If all inner interfaces between the LSC function block and the PSC function block are reserved, the LSR shall be identified as the PSC+LSC router which has no OLSP ternination capability. If the PSC function block is in failure, the LSR shall be identified as the PSC+LSC router which has no usable PSC. _______ | | __| PSC |__ | |_______| | | /|\ \|/ _______ | |__| |__| __\ /|___| |___|\ Imajuku [Page 4] Internet Draft draft-imajuku-ml-routing-00.txt 22 February 2002 / | |___| |___| | Fiber #1 ========| |___| LSC |___| |======== | |___| |___| | \| | | |/ | | . . . . __\ /|___| |___|\ / | |___| |___| | Fiber #N ========| |___| |___| |======== | |___| |___| | \| | | |/ |_______| 3. Multi-layer routing aspects In this section, we explain routing aspects in generic LSP+OLSP multi-layer network comprising LSRs with only LSC and PSC+LSC. In such multi-layer network, an LSP layer has LSP switching capability comprises PSC-LSRs and PSC+LSC-LSRs. On the other hand, an OLSP layer has OLSP switching capability comprises LSC-LSRs and PSC+LSC-LSRs. Therefore, the LSR with PSC+LSC should have both layers link states and network topology data to realize both LSP and OLSP route selection. To provide the route selection functionality, the LSR should discriminate link state data to which layer these belong. Path route selection of LSPs and OLSPs should be done in reference to link state data corresponding with each layer. The link state of existing OLSP within the multi-layer GMPLS network can be advertised as point to point link by using conventional Router LSA in the case of OSPF. This enables the conventional IP routers which are connected to the multi-layer GMPLS network can realize IP network plane topology within the network. Alternatively, the link state of existing OLSP can be advertised by conforming to the concept of FA-LSPs [LSP-HIER]. The OLSP can be identified as the links forming "forwarding adjacency" (FA) between LSRs connected by the OLSP. The corresponding LSA of the FA-OLSP should contain the interface switching capability descriptor which indicates the OLSP being terminated by PSCs and configure IP network Imajuku [Page 5] Internet Draft draft-imajuku-ml-routing-00.txt 22 February 2002 layer topology. The forwarding of IP packet or LSPs shall be done by using the next-hop database created from this network topology data. The link state of existing fiber-link can be advertised by conforming to the concept of TE extension to routing protocols [TE-OSPF] -[TE-ISIS]. The fiber links connected to LSRs are identified as TE-links which forms "routing adjacency" between LSRs. The corresponding LSA of the TE-Fiber Link shall contain the interface switching capability descriptor which indicates the fiber link being terminated by LSCs and configure OLSP network layer topology. The routing of OLSPs shall be done by using the next-hop database created from this network topology data. Also, these LSRs with the integrated PSC+LSC switching capabilities should be required to advertise resource information of the switching capability. The surficial capability of the integrated switching node capability should be varied as the state of the resource utilization as discussed in previous section. The route of OLSPs can be calculated with the selection of LSCs which has OLSP forwarding or termination capability and fiber links which has unreserved wavelength channel. Thus, the LSR can have multi-layer routing capability which enables IP packet forwarding route considering both existing OLSP and fiber-link state. If unused bandwidth of each OLSP is not enough, new OLSP can be automatically set-up triggered by IP-traffic surge or LSP setup calls. This means the LSR can realize IP-centric flexible Photonic network essential to next generation of large capacity back-bone network. 4. Enhancements to interface switching capabilities descriptor The draft of [GMPLS-OSPF] defines the Interface Switching Capability Descriptor with a sub-TLV of the Link TLV with type 15. The length is the length of value field in octets. The Switching Capability (Switching Cap) field contains one of the following values: Imajuku [Page 6] Internet Draft draft-imajuku-ml-routing-00.txt 22 February 2002 1 Packet-Switch Capable-1 (PSC-1) 2 Packet-Switch Capable-2 (PSC-2) 3 Packet-Switch Capable-3 (PSC-3) 4 Packet-Switch Capable-4 (PSC-4) 51 Layer-2 Switch Capable (L2SC) 100 Time-Division-Multiplex Capable (TDM) 150 Lambda-Switch Capable (LSC) 200 Fiber-Switch Capable (FSC) If there is no Interface Switching Capability Descriptor for an interface, the interface is assumed to be packet-switch capable (PSC-1). Interface Switching Capability Descriptors present a new constraint for LSP path computation. The detail extentions to Interface Switching Capability Descriptor for integrated PSC/LSC LSR will be discussed in next version of this document. 5. Security Considerations Security issues are not discussed in this draft. 6. References [SHIMANO01] K. Shimano, F. Kano, Y. Takigawa, and K. -I. Sato, "MPLambdaS Demonstration Employing Photonic Routers (256X256 OLSPS) To Integrate Optical and IP Networks," National Fiber Optic Engineers Conf. 2001 Tech.Proc. p. 5. [OKI02] E. Oki, K. Shiomoto, S. Okamoto, W. Imajuku, and N. Yamanaka, A heuristic-based multi-layer optimum topology design scheme based on traffic measurement for IP+Photonic networks," In Proc. of OFC 2002, 3/2002. [GMPLS-ROUT] "Routing extensions in support of generalized MPLS, " draft-many-ccamp-gmpls-routing-01.txt (work in progress), 6/01. Imajuku [Page 7] Internet Draft draft-imajuku-ml-routing-00.txt 22 February 2002 [GMPLS-OSPF] "OSPF extensions in support of generalized MPLS, " draft-ietf-ccamp-ospf-gmpls-extensions-03.txt (work in progress), 9/01. [OKI-OLI] "Requirements of optical link-state information for traffic engineering," draft-oki-ipo-optlink-req-00.txt, 02/02. [LSP-HIER] "LSP hierarchy with MPLS TE," draft-ietf-mpls- lsp-hierarchy-02.txt (work in progress), 02/01. [TE-OSPF] "Traffic engineering extensions to OSPF," draft-katz-yeung -ospf-traffic-06.txt, 10/01. [TE-ISIS] "IS-IS extensions for Traffic Engineering," draft-ietf-isis -traffic-04.txt, 08/01. [GMPLS-SIG] "Generalized MPLS-signaling functional description, " draft-ietf-mpls-generalized-signaling-07.txt (work in progress), 11/01. 7. Author information Wataru Imajuku NTT Network Innovation Laboratories 1-1 Hikari-no-oka, Yokosuka, Kanagawa, 239-0847 Japan Email: imajyuku@exa.onlab.ntt.co.jp Eiji Oki NTT Network Innovation Laboratories 3-9-11 Midori-cho, Musashino-shi, Tokyo 180-8585, Japan Phone: +81 422 59 3441 Fax: +81 422 59 6387 Email: oki.eiji@lab.ntt.co.jp Imajuku [Page 8] Internet Draft draft-imajuku-ml-routing-00.txt 22 February 2002 Kohei Shiomoto NTT Network Innovation Laboratories 3-9-11 Midori-cho, Musashino-shi, Tokyo 180-8585, Japan Phone: +81 422 59 4402 Fax: +81 422 59 6387 Email: shiomoto.kohei@lab.ntt.co.jp Satoru Okamoto NTT Network Innovation Laboratories 1-1 Hikari-no-oka, Yokosuka, Kanagawa, 239-0847 Japan Email: okamoto@exa.onlab.ntt.co.jp Imajuku [Page 9]