Internet Draft Lou Berger (LabN Consulting, LLC) Category: Experimental Expiration Date: December 25, 2008 June 25, 2008 OSPFv3 Based Layer 1 VPN Auto-Discovery draft-ietf-l1vpn-ospfv3-auto-discovery-01.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/1id-abstracts.html The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html This Internet-Draft will expire on December 25, 2008. Copyright Notice Copyright (C) The IETF Trust (2008). Abstract This document defines an Open Shortest Path First (OSPF) version 3 based Layer-1 Virtual Private Network (L1VPN) auto-discovery mechanism. This document parallels the existing OSPF version 2 L1VPN auto-discovery mechanism. The notable functional difference is the support of IPv6. Berger Experimental [Page 1] Internet-Draft draft-ietf-l1vpn-ospfv3-auto-discovery-01.txt June 25, 2008 Table of Contents 1 Introduction .............................................. 3 1.1 Terminology ............................................... 3 1.2 Overview .................................................. 4 2 OSPFv3 L1VPN LSA and its TLVs ............................. 5 2.1 OSPFv3 L1VPN LSA .......................................... 5 2.2 L1VPN IPv6 INFO TLV ....................................... 6 3 OSPFv3 L1VPN LSA Advertising and Processing ............... 8 4 Backward Compatibility .................................... 8 5 Security Considerations ................................... 9 6 IANA Considerations ....................................... 9 7 Acknowledgment ............................................ 9 8 References ................................................ 9 8.1 Normative References ...................................... 9 8.2 Informative References .................................... 10 9 Authors' Addresses ........................................ 10 10 Full Copyright Statement .................................. 10 11 Intellectual Property ..................................... 11 Berger Experimental [Page 2] Internet-Draft draft-ietf-l1vpn-ospfv3-auto-discovery-01.txt June 25, 2008 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]. 1. Introduction 1.1. Terminology The reader of this document should be familiar with the terms used in [RFC4847] and [RFC5251]. The reader of this document should also be familiar with [RFC2740], [OSPFv3-TE], and [RFC5252]. In particular the following terms: L1VPN - Layer One Virtual Private Network CE - Customer (edge) network element directly connected to the Provider network (terminates one or more links to one or more PEs); it is also connected to one or more Cs and/or other CEs C - Customer network element that is not connected to the Provider network but is connected to one or more other Cs and/or CEs PE - Provider (edge) network element directly connected to one or more Customer networks (terminates one or more links to one or more CEs associated with the same or different L1VPNs); it is also connected to one or more Ps and/or other PEs P - Provider (core) network element that is not directly connected to any of Customer networks; P is connected to one or more other Ps and/or PEs LSA - OSPF Link State Advertisement LSDB - Link State Database: a data structure supported by an IGP speaker PIT - Port Information Table CPI - Customer Port Identifier PPI - Provider Port Identifier Berger Experimental [Page 3] Internet-Draft draft-ietf-l1vpn-ospfv3-auto-discovery-01.txt June 25, 2008 1.2. Overview The framework for Layer 1 VPNs is described in [RFC4847]. Basic mode operation is further defined in [RFC5251]. [RFC5251] identifies the information that is necessary to map customer information (port identifiers) to provider information (identifiers). It also states that this mapping information may be provided via provisioning or via an auto-discovery mechanism. [RFC5252] provides such an auto- discovery mechanism using Open Shortest Path First (OSPF) version 2. This document provides the same functionality using of OSPF version 3 and adds support for IPv6. Figure 1 shows the L1VPN basic service being supported using OSPF based L1VPN auto-discovery. This figure shows two PE routers interconnected over a GMPLS backbone. Each PE is attached to three CE devices belonging to three different Layer 1 VPNs. In this network, OSPF is used to provide the VPN membership, port mapping and related information required to support basic mode operation. PE PE +---------+ +--------------+ +--------+ | +------+| | +----------+ | +--------+ | VPN-A | | |VPN-A || | | VPN-A | | | VPN-A | | CE1 |--| |PIT || OSPF LSAs | | PIT | |-| CE2 | +--------+ | | ||<----------->| | | | +--------+ | +------+| Distribution| +----------+ | | | | | +--------+ | +------+| | +----------+ | +--------+ | VPN-B | | |VPN-B || ------- | | VPN-B | | | VPN-B | | CE1 |--| |PIT ||--( GMPLS )--| | PIT | |-| CE2 | +--------+ | | || (Backbone) | | | | +--------+ | +------+| -------- | +----------+ | | | | | +--------+ | +-----+ | | +----------+ | +--------+ | VPN-C | | |VPN-C| | | | VPN-C | | | VPN-C | | CE1 |--| |PIT | | | | PIT | |-| CE2 | +--------+ | | | | | | | | +--------+ | +-----+ | | +----------+ | +---------+ +--------------+ Figure 1: OSPF Auto-Discovery for L1VPNs The approach used in this document to provide OSPFv3 based L1VPN auto-discovery uses a new type of Link State Advertisement (LSA) which is referred to as an OSPFv3 L1VPN LSA. The OSPFv3 L1VPN LSA carries information in TLV (type, length, value) structures. An L1VPN specific TLV is defined below to propagate VPN membership and port information. This TLV is is referred to as the L1VPN Info TLV. Berger Experimental [Page 4] Internet-Draft draft-ietf-l1vpn-ospfv3-auto-discovery-01.txt June 25, 2008 The OSPFv3 L1VPN LSA may also carry Traffic Engineering (TE) TLVs, see [RFC3630], [RFC4203], and [OSPFv3-TE]. 2. OSPFv3 L1VPN LSA and its TLVs This section defines the OSPFv3 L1VPN LSA and its TLVs. 2.1. OSPFv3 L1VPN LSA The format of a OSPFv3 L1VPN LSA is as follows: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | LS age | LS type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Link State ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Advertising Router | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | LS sequence number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | LS checksum | length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | L1VPN Info TLV | | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | TE Link TLV | | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ LS age As defined in [RFC2740]. LS type As defined in [RFC2740]. The U-bit MUST be set to 1, and the S1 and S2 bits MUST be set to indicate either area or AS scoping. The LSA Function Code portion of this field MUST be set to TBA (by IANA), i.e., the OSPFv3 L1VPN LSA. Advertising Router As defined in [RFC2740]. LS Sequence Number As defined in [RFC2740]. Berger Experimental [Page 5] Internet-Draft draft-ietf-l1vpn-ospfv3-auto-discovery-01.txt June 25, 2008 LS checksum As defined in [RFC2740]. Length As defined in [RFC2740]. L1VPN Info TLV A single L1VPN Info TLV, as defined in section 2.2 of [RFC5252] or section 2.2 of this document, MUST be present. If more than one L1VPN Info TLV is present, only the first TLV is processed and the others MUST be ignored on receipt. TE Link TLV A single TE Link TLV MAY be included in an OSPFv3 L1VPN LSA. When an L1VPN IPv4 Info TLV is present, a single TE Link TLV as defined in [RFC3630] and [RFC4203] MAY be included. When an L1VPN IPv6 Info TLV is present, a single TE Link TLV as defined in [OSPFv3-TE] MAY be included. 2.2. L1VPN IPv6 INFO TLV The following TLV is introduced: Name: L1VPN IPv6 Info Type: 2 Length: Variable Berger Experimental [Page 6] Internet-Draft draft-ietf-l1vpn-ospfv3-auto-discovery-01.txt June 25, 2008 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | L1VPN TLV Type | L1VPN TLV Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | L1VPN Globally Unique Identifier | | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | PE TE Address | | ... | | ... | | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Link Local Identifier | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | | L1VPN Auto-Discovery Information | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | .| Padding | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ L1VPN TLV Type The type of the TLV (see above). TLV Length The length of the TLV in bytes, excluding the four (4) bytes of the TLV header and, if present, the length of the Padding field. L1VPN Globally Unique Identifier As defined in [RFC5251]. PE TE Address This field MUST carry an address that has been advertised by the LSA originator per [OSPFv3-TE] and is either the Router Address TLV or Local interface IP address link sub-TLV. It will typically carry the TE Router Address. Link Local Identifier This field is used to support unnumbered links. When an unnumbered PE TE link is represented, this field MUST contain a value advertised by the LSA originator per [RFC2740] in a Router LSA. When a numbered link is represented, this field MUST be set to zero (0). L1VPN Auto-discovery information As defined in [RFC5251]. Berger Experimental [Page 7] Internet-Draft draft-ietf-l1vpn-ospfv3-auto-discovery-01.txt June 25, 2008 Padding A field of variable length and of sufficient size to ensure that the TLV is aligned on a four (4) byte boundary. This field is only required when the L1VPN Auto-discovery information field is not four (4) byte aligned. This field MUST be less than four (4) bytes long, and MUST NOT be present when the size of L1VPN Auto-discovery information field is four (4) byte aligned. 3. OSPFv3 L1VPN LSA Advertising and Processing PEs advertise local tuples in OSPFv3 L1VPN LSAs containing L1VPN Info TLVs. Each PE MUST originate a separate OSPFv3 L1VPN LSA with AS flooding scope for each local CE-PE link. The LSA MUST be originated each time a PE restarts and every time there is a change in the PIT entry associated with a local CE-PE link. The LSA MUST include a single L1VPN Info TLV and MAY include a single TE Link TLV. The TE Link TLV carries TE attributes of the associated CE-PE link. Note that because CEs are outside of the provider TE domain, the attributes of CE-PE links are not advertised via normal OSPF-TE procedures as described in [OSPFv3-TE]. If more than one L1VPN Info TLVs and/or TE Link TLVs are found in the LSA, the subsequent TLVs SHOULD be ignored by the receiving PEs. Every time a PE receives a new, removed, or modified OSPFv3 L1VPN LSA, the PE MUST check whether it maintains a PIT associated with the L1VPN specified in the L1VPN Globally unique identifier field. If this is the case (the appropriate PIT will be found if one or more local CE-PE links that belong to the L1VPN are configured), the PE SHOULD add, remove or modify the PIT entry associated with each of the advertised CE-PE links accordingly. (An implementation MAY choose to not remove or modify the PIT according to local policy or management directives.) Thus, in the normal steady-state case, all PEs associated with a particular L1VPN will have identical local PITs for an L1VPN. 4. Backward Compatibility Neither the TLV nor the LSA introduced in this document present any interoperability issues. Per [RFC2740] and due to the U-bit being set, OSPFv3 speakers that do not support the OSPFv3 L1VPN LSA (Ps for example) just participate in the LSAs flooding process but should ignore the LSAs contents. Berger Experimental [Page 8] Internet-Draft draft-ietf-l1vpn-ospfv3-auto-discovery-01.txt June 25, 2008 5. Security Considerations The approach presented in this document describes how PEs dynamically learn L1VPN specific information. Mechanisms to deliver the VPN membership information to CEs are explicitly out of scope of this document. Therefore, the security issues raised in this document are limited to within the OSPF domain. This defined approach reuses mechanisms defined in [RFC2740]. Therefore the same security approaches and considerations apply to this approach. OSPF provides several security mechanisms that can be applied. Specifically, OSPF supports multiple types of authentication, limits the frequency of LSA origination and acceptance, and provides techniques to avoid and limit impact database overflow. In cases were end-to-end authentication is desired, OSPF's neighbor-to-neighbor authentication approach can be augmented with an approach similar to the experimental extension to OSPF, see [RFC2154], which supports the signing and authentication of LSAs. 6. IANA Considerations Section 2.1 of this document requests the assignment of an OSPFv3 LSA Function Code, see http://www.iana.org/assignments/ospfv3-parameters. IANA is requested to make an assignment in the form: Value OSPFv3 LSA type function Type Reference ------- ----------------------------- --------- TBA OSPFv3 L1VPN LSA [this document] A value of 13 is suggested for TBA. 7. Acknowledgment This document was created at the request of Pasi Eronen. Adrian Farrel provided a valuable review of this draft. 8. References 8.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to indicate requirements levels", RFC 2119, March 1997. Berger Experimental [Page 9] Internet-Draft draft-ietf-l1vpn-ospfv3-auto-discovery-01.txt June 25, 2008 [RFC2740] R. Coltun, D. Ferguson, J. Moy, "OSPF for IPv6", RFC 2740. [RFC3630] Katz, D., Kompela, K., Yeung. D.., "Traffic Engineering (TE) Extensions to OSPF Version 2", RFC 3630, September 2003. [RFC4203] Kompela, K., Rekhter, Y. "OSPF Extensions in Support of Generalized Multi-Protocol Label Switching (GMPLS)", RFC 4203, October 2005. [RFC5251] Fedyk, D., Ed., Rekhter, Y., Ed., Papadimitriou, D., Rabbat, R., and L. Berger, "Layer 1 VPN Basic Mode", RFC 5251, June 2008. [RFC5252] Bryskin, I. and L. Berger, "OSPF-Based Layer 1 VPN Auto-Discovery", RFC 5252, June 2008. [OSPFv3-TE] K. Ishiguro, T. Takada, "Traffic Engineering Extensions to OSPF version 3", work in progress, draft-ietf-ospf-ospfv3-traffic 8.2. Informative References [RFC2154] Murphy, S., Badger, M., Wellington, B., "OSPF with Digital Signatures", RFC 2154, June 1997. [RFC4847] Tomonori Takeda, Ed., "Framework and Requirements for Layer 1 Virtual Private Networks", RFC 4847, April 2007. 9. Authors' Addresses Lou Berger LabN Consulting, LLC Email: lberger@labn.net 10. Full Copyright Statement Copyright (C) The IETF Trust (2008). 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 Berger Experimental [Page 10] Internet-Draft draft-ietf-l1vpn-ospfv3-auto-discovery-01.txt June 25, 2008 "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST 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. 11. Intellectual Property The IETF takes no position regarding the validity or scope of any Intellectual Property Rights 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; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat 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 on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Acknowledgement Funding for the RFC Editor function is provided by the IETF Administrative Support Activity (IASA). Berger Experimental [Page 11] Generated on: Wed Jun 25 16:49:04 EDT 2008