Network Working Group Z. Li Internet-Draft Q. Zhao Intended status: Standards Track Huawei Technologies Expires: April 24, 2014 October 21, 2013 IS-IS Extensions for MPLS Multi-Topology draft-li-isis-mpls-multi-topology-00 Abstract MPLS plays a key role in the process of implementing network virtualization. [I-D.li-mpls-network-virtualization-framework] proposes the framework to implement MPLS virtual network basedn on the architecture of central controller IGP. This document defines the corresponding IS-IS protocol extension and procedures to support MPLS Multi-Topology. 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]. 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 April 24, 2014. 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 Li & Zhao Expires April 24, 2014 [Page 1] Internet-Draft IS-IS Extensions for MPLS MT October 2013 (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 . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2 3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3.1. Application for MRT FRR . . . . . . . . . . . . . . . . . 3 4. IS-IS Extensions . . . . . . . . . . . . . . . . . . . . . . 4 4.1. IS-IS Label Mapping TLV . . . . . . . . . . . . . . . . . 4 4.2. Label Sub-TLV . . . . . . . . . . . . . . . . . . . . . . 5 4.3. MPLS Multi-Topology Sub-TLV . . . . . . . . . . . . . . . 6 4.4. Procedures . . . . . . . . . . . . . . . . . . . . . . . 6 5. Compatibility . . . . . . . . . . . . . . . . . . . . . . . . 6 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 7. Security Considerations . . . . . . . . . . . . . . . . . . . 7 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 7 8.1. Normative References . . . . . . . . . . . . . . . . . . 7 8.2. Informative References . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8 1. Introduction As the virtual network operators develop, it is desirable to provide better network virtualization solutions to facilitate the service provision. [I-D.li-mpls-network-virtualization-framework] proposes a new framework to implement MPLS virtual network based on the architecture of central controlled IGP. It is to allocate MPLS global label for the virtual network topologies, network nodes and links by an IGP controller to IGP clients. Thus MPLS global labels becomes the unique identifications in the underlying networks to compose the virtual networks. This document defines the corresponding IS-IS protocol extensions and procedures to support MPLS virtual network topology. The other document will define the corresponding IS-IS protocol extensions and procedures to support MPLS virtualized network nodes and links. 2. Terminology Li & Zhao Expires April 24, 2014 [Page 2] Internet-Draft IS-IS Extensions for MPLS MT October 2013 Underlying Network: It is the network which the virtual network is built based on. The underlying network can be the physical network or the virtual network. MPLS Virtual Network: The virtual network is built based on the underlying network. It is composed by virtual nodes and virtual links which are identified by MPLS global label. In this document, the concept of virtual network is the same as that of MPLS virtual network. MPLS Virtual Network Topology: It is the topology of the MPLS virtual network. It can be identified multi-topology ID of corresponding virtual network. MPLS global label is allocated to represent the virtual network topology. 3. Overview [I-D.li-rtgwg-cc-igp-arch] defines the central controlled architecture for IGP. In [I-D.li-mpls-network-virtualization-framework], a new framework is defined to implement MPLS virtual network based on central controlled IGP. In the MPLS virtual network, the virtual network topology can be identified by the Multi-Topology ID. The global label for the virtual network topology is allocated by the IGP controller and the label binding between the Multi-Topology ID and the Global Label are flooded from the IGP controller to IGP clients. When IGP clients receives the label binding, it can install the MPLS forwarding entry to map the incoming label to the forwarding instance corresponding to the Multi-Topology. 3.1. Application for MRT FRR MRT FRR [I-D.ietf-rtgwg-mrt-frr-architecture] has been proposed to provide 100% coverage of FRR deployment in the network. There are two forwarding mechanisms defined in : IP tunnel forwarding mechanism and LDP Multi-Topology mechanism. IP tunnel forwarding mechanism need to set up IP tunnels which must introduce extra IP addresses. It is difficult to satisfy the scalability requirement for deployment. LDP Multi-Topology is a scalable way to implement the MRT FRR forwarding. But for the pure IP network it has to introduce the new MPLS protocol. Moreover, it may use more labels which are allocated for prefixes in three topologies: the default topology, the blue topology and the red topology. When the MPLS virtual network mechanism is introduced, the MRT FRR forwarding in the IP network can be simplified greatly. Two MPLS global label can be allocated to identify the blue topology and the red topology. According to MRT calculation, the forwarding instances Li & Zhao Expires April 24, 2014 [Page 3] Internet-Draft IS-IS Extensions for MPLS MT October 2013 for the default topology, the red topology and the blue topology can be installed. For a specific IP prefix, the forwarding entry will consist of the primary path in the default topology and the secondary path in the red topology or the blue topology. IP packets will forward hop by hop according to the FIB of the default topology. When failure happens, they will be forwarded in the blue topology or the red topology which contains the secondary path. When forwarding, the global label for the Multi-Topology is encapsulated for the IP packets. When the next hop node receives the packets, it will decapsulate the label and map to the corresponding forwarding instance of the red topology or the blue topology according to the MPLS forwarding entry. When determine the outgoing interface and the next hop after looking up the Multi-Topology FIB according to the destination IP address, the packet will encapsulate the global label again which represent the red topology or the blue topology and will be forwarded to the next hop. This forwarding process will be done by each node until it reaches the destination. In the MRT FRR process, there are only two MPLS forwarding entries to map the label to the red topology and the blue topology. Moreover, it is done by IGP extensions instead of introducing LDP, which can also simplify the network operation and management. 4. IS-IS Extensions 4.1. IS-IS Label Mapping TLV A new IS-IS TLV, call as Label Mapping TLV, is introduced to allocate MPLS label. The IS-IS Label Mapping TLV format is shown in the following figure. The type of IS-IS Label Mapping TLV is to be defined by IANA. The flags in the TLV are to be defined. There are a series of sub-TLV in the TLV which length can be up to 252 octets. There MUST be at least one Label Sub-TLV and one FEC sub-TLV in the TLV. The Label sub-TLV contains the label value allocated. The FEC sub-TLV contains the Forwarding Equivalent Class for which the label is allocated. In this document, one FEC sub-TLV is defined, called as MPLS Multi-Topology sub-TLV. 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 | Flags | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Label Sub-TLV | . . . . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Li & Zhao Expires April 24, 2014 [Page 4] Internet-Draft IS-IS Extensions for MPLS MT October 2013 | FEC Sub-TLV | . . . . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: IS-IS Label Mapping TLV format 4.2. Label Sub-TLV As defined in [I-D.li-mpls-global-label-framework], there are two types of methods to allocated global label: the first one is to use the existing MPLS label range, that is, from 16 to 2^20; the second one is to use the expanded MPLS label range which can be more than 2^20. Taking into account the future expansion, the Label Sub-TLV has following format: 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Label (24 bits) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ...... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Label (24 bits) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2: Label Sub-TLV Format o Type: 1 octet of sub-TLV type. It is to be allocated by IANA. o Length: 1 octet of length of the value field of the sub-TLV. It can be up to 252 octets. o MPLS Label Field: variable length. It consists of one or more labels. Each label is encoded as 3 octets, where the high-order 20 bits contain the label value, and the low order bit contains "Bottom of Stack". The label stack in the Label sub-TLV can construct a big label range which can exceed 2^20. If there is only one label field, it is consistent with the existing MPLS label range from 16 to 2^20. Li & Zhao Expires April 24, 2014 [Page 5] Internet-Draft IS-IS Extensions for MPLS MT October 2013 4.3. MPLS Multi-Topology Sub-TLV When implement virtual topology, the global label is allocated for the Multi-topology ID. MPLS Multi-Topology ID can be seen as the FEC for the label mapping. The MPLS Multi-Topology sub-TLV format has following format: 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Multi-Topology ID (32 bits) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3: Multi-Topology Sub- TLV format o Type: 1 octet of sub-TLV type. It is to be allocated by IANA. o Length: 1 octet of length of the value field of the sub-TLV. It is 4. o Multi-Topology ID: 4 octets. It contains the MPLS Multi-Topology ID for which the global label is allocated to implement virtual topology. 4.4. Procedures When the IGP controller needs to implement the MPLS virtual network topology, the IGP controller MUST originate a new LSP comprising the Label Mapping TLV for the MPLS virtual network topology. The Label Mapping TLV MUST contain one or more pairs of the Label sub-TLV and the Multi-Topology ID sub-TLV. If the length of these sub-TLVs can exceeds 252 octets, there SHOULD be multiple Label Mapping TLVs in IS-IS LSP. When receiving the Label Mapping to implement the virtual network topology, the IGP clients SHOULD get the global label and the corresponding multi-topology from the sub-TLVs in the label mapping TLV and install MPLS fowarding entry accordingly. 5. Compatibility Routers that do not support these MPLS Virtualization extensions SHOULD silently ignore the TLV and the sub-TLVs defined in this document. Li & Zhao Expires April 24, 2014 [Page 6] Internet-Draft IS-IS Extensions for MPLS MT October 2013 6. IANA Considerations This document request to allocate a type value for the Label Mapping TLV, a type value for the Label sub-TLV and a type value for the MPLS Multi-Topology sub-TLV. 7. Security Considerations TBD. 8. References 8.1. Normative References [I-D.li-mpls-global-label-framework] Li, Z., Zhao, Q., and T. Yang, "A Framework of MPLS Global Label", draft-li-mpls-global-label-framework-00 (work in progress), July 2013. [I-D.li-mpls-network-virtualization-framework] Li, Z. and M. Li, "Framework of Network Virtualization Based on MPLS Global Label", draft-li-mpls-network- virtualization-framework-00 (work in progress), October 2013. [I-D.li-rtgwg-cc-igp-arch] Li, Z., Chen, H., and G. Yan, "An Architecture of Central Controlled Interior Gateway Protocol (IGP)", draft-li- rtgwg-cc-igp-arch-00 (work in progress), October 2013. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. 8.2. Informative References [I-D.gredler-isis-label-advertisement] Gredler, H., Amante, S., Scholl, T., and L. Jalil, "Advertising MPLS labels in IS-IS", draft-gredler-isis- label-advertisement-03 (work in progress), May 2013. [I-D.ietf-rtgwg-mrt-frr-architecture] Atlas, A., Kebler, R., Envedi, G., Csaszar, A., Tantsura, J., Konstantynowicz, M., and R. White, "An Architecture for IP/LDP Fast-Reroute Using Maximally Redundant Trees", draft-ietf-rtgwg-mrt-frr-architecture-03 (work in progress), July 2013. [I-D.previdi-isis-segment-routing-extensions] Li & Zhao Expires April 24, 2014 [Page 7] Internet-Draft IS-IS Extensions for MPLS MT October 2013 Previdi, S., Filsfils, C., Bashandy, A., Gredler, H., and S. Litkowski, "IS-IS Extensions for Segment Routing", draft-previdi-isis-segment-routing-extensions-02 (work in progress), July 2013. Authors' Addresses Zhenbin Li Huawei Technologies Huawei Bld., No.156 Beiqing Rd. Beijing 100095 China Email: lizhenbin@huawei.com Quintin Zhao Huawei Technologies Boston, MA USA Email: quintin.zhao@huawei.com Li & Zhao Expires April 24, 2014 [Page 8]