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Versions: 00 01 draft-ietf-l1vpn-ospf-auto-discovery

Internet Draft                             Igor Bryskin (Movaz Networks)
Category: Standards Track              Lou Berger (LabN Consulting, LLC)
Expiration Date: October 2006

                                                              April 2006


                    OSPF Based L1VPN Auto-Discovery


             draft-bryskin-l1vpn-ospf-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

Abstract

   This document defines an OSPF based layer-1 VPN auto-discovery
   mechanism.  This mechanism enables PEs using the OSPF IGP to
   dynamically learn about existence of each other, and attributes of
   currently configured CE-PE links and their associations with L1VPNs.
   This document builds on [L1VPN-FRMWK] and provides an auto-discovery
   mechanism as discussed in [L1VPN-BM].













Bryskin, Berger                                                 [Page 1]


Internet Draft draft-bryskin-l1vpn-ospf-auto-discovery-01.txt   April 2006


Contents

 1      Terminology  ...............................................   3
 2      Introduction  ..............................................   4
 3      L1VPN LSA and its TLVs  ....................................   5
 3.1    L1VPN LSA  .................................................   5
 3.2    L1VPN INFO TLV  ............................................   6
 4      L1VPN LSA Advertising and Processing  ......................   7
 4.1    Discussion and Example  ....................................   7
 5      Backward compatibility  ....................................   8
 6      Security Considerations  ...................................   9
 7      Intellectual Property Statement  ...........................   9
 8      Acknowledgement  ...........................................  10
 9      References  ................................................  10
 9.1    Normative References  ......................................  10
 9.2    Informative References  ....................................  10
10      Authors' Addresses  ........................................  11
11      Full Copyright Statement  ..................................  11
12      Intellectual Property  .....................................  11



Internet Draft draft-bryskin-l1vpn-ospf-auto-discovery-01.txt   April 2006


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. Terminology

   The reader of this document should be familiar with the terms used in
   [L1VPN-FRMWK] and [L1VPN-BM].  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

   LSDB - Link State Database: a data structure supported by an IGP
          speaker

   PIT - Port Information Table

   CPI - Customer Port Identifier

   PPI - Provider Port Identifier











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2. Introduction

   The framework for Layer 1 VPNs is described in [L1VPN-FRMWK].  Basic
   mode operation is further defined in [L1VPN-BM].  [L1VPN-BM] document
   identifies the information that is necessary to map customer
   information (ports identifiers) to provider information
   (identifiers).  It also states that this mapping information may be
   provided via provisioning or via an auto-discovery mechanism.  This
   document provides such an auto-discovery mechanism using the OSPF
   IGP.  Figure 1 shows the L1VPN basic service being supported using
   OSPF based L1VPN auto-discovery.  See [L1VPN-BGP] for a parallel
   L1VPN auto-discovery that uses BGP.  The IGP approach described in
   this document is particularly useful in networks where BGP is not
   typically used.

                  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 OSPF based L1VPN auto-
   discovery uses an Opaque LSA of a new Opaque Type (referred as a
   L1VPN LSA).

   There is a TLV type defined for use within a L1VPN LSA. The TLV,
   which is referred to as L1VPN Info TLV, is used to propagate <CPI,
   PPI> tuple and VPIN ID mappings.






Bryskin, Berger                                                 [Page 4]


Internet Draft draft-bryskin-l1vpn-ospf-auto-discovery-01.txt   April 2006


3. L1VPN LSA and its TLVs

   This section defines the L1VPN LSA and its TLVs.


3.1. L1VPN LSA

   The format of a 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             |     Options   |  LS Type      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Opaque Type  |               Opaque ID                       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                      Advertising Router                       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                      LS Sequence Number                       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |         LS checksum           |           Length              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                           L1VPN Info TLV                      |
   |                             ...                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                            TE Link TLV                        |
   |                             ...                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   LS age
      As defined in [RFC2328]

   Options
      As defined in [RFC2328].

   LS Type
      This field MUST be set to 11.

   Opaque Type
      The value of this field MUST be set to TBA (by IANA).

   Opaque ID
      As defined in [RFC2370]

   Advertising Router
      As defined in [RFC2328].

   LS Sequence Number



Bryskin, Berger                                                 [Page 5]


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      As defined in [RFC2328].

   LS checksum
      As defined in [RFC2328].

   Length
      As defined in [RFC2328].


   L1VPN Info TLV
      A single TLV, as defined in section 3.2

   TE Link TLV
      A single TE Link TLV (as defined in [RFC3630] and [RFC4203])
      MAY be included in a L1VPN LSA



3.2. L1VPN INFO TLV

   The following TLV is introduced:

   Name: L1VPN IPv4 Info
   Type: 1
   Length: Variable

    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 length      |           L1VPN TLV Type      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                 L1VPN Globally unique identifier              |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        PE TE Address                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                              ...                              |
   |                 L1VPN Auto-Discovery Information              |
   |                              ...                              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   TLV length
      The length of the TLV in bytes, including the 4 bytes of
      the TLV header.

   L1VPN TLV Type
      The type of the TLV.




Bryskin, Berger                                                 [Page 6]


Internet Draft draft-bryskin-l1vpn-ospf-auto-discovery-01.txt   April 2006


   L1VPN Globally unique identifier
      As defined in [L1VPN-BM].


   PE TE Address
      Valid PE TE address: either TE Router ID specified in the
      Router Address TLV or local numbered TE link ID specified in
      the Local interface IP address sub-TLV of the TE Link TLV of the
      TE LSA originated by the PE

   L1VPN Auto-discovery information
      As defined in [L1VPN-BM].


4. L1VPN LSA Advertising and Processing

   PEs advertise local <CPI, PPI> tuples in L1VPN LSAs containing L1VPN
   Info TLVs. Each PE MUST originate a separate L1VPN LSA with AS
   flooding scope for each local CE-PE link. The LSA MUST be originated
   once on the PE restart and every time when 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 as per
   [RFC 3630] and [RFC 4203].

   L1VPN LSAs are flooded to all PEs within the AS according to [RFC
   2370]. Every time a PE receives a new, removed or modified such 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. Thus, in the steady mode all
   PEs associated with a particular L1VPN maintain identical local PITs
   for the L1VPN.


4.1. Discussion and Example

   The L1VPN auto-discovery mechanism described in this document does
   not prevent a PE from applying any local policy with respect to PIT
   management. For example, it should be possible to configure permanent
   (static) PIT entries, blocking information carried in L1VPN LSAs that
   are advertised by some remote PEs from making it to the PITs and so
   forth.

   The reason why it is required that the value specified in the PE TE
   Address field of the L1VPN Info TLV matches a valid PE TE Router ID
   or numbered TE Link ID is to ensure that CEs attached to this PE



Bryskin, Berger                                                 [Page 7]


Internet Draft draft-bryskin-l1vpn-ospf-auto-discovery-01.txt   April 2006


   could be resolved to the PE as it is known to the Traffic Engineering
   Database (TED) and hence TE paths towards the CEs across the Provider
   domain could be computed.

   Let us consider example presented on Figure 2.


                            CE11               CE13
                              |                 |
                      CE22---PE1--------P------PE2
                              |         |
                             CE15      PE3
                              |
                             CE24

                    Figure 2: Single area configuration

   Let us assume that PE1 is connected to CE11 and CE15 in L1VPN1 and to
   CE22 in L1VPN2; PE2 is connected to CE13 in L1VPN1; PE3 is connected
   to CE24 in L1VPN2. In this configuration PE1 manages two PITs: PIT1
   for L1VPN1 and PIT2 for L1VPN2; PE2 manages only PIT1, and PE3
   manages only PIT2. PE1 originates three L1VPN LSAs, each containing a
   L1VPN Info TLV advertising links PE1-CE11, PE1-CE22 and PE1-CE15
   respectively. PE2 originates a single L1VPN LSA for link PE2-CE13 and
   PE3 originates a single L1VPN LSA for link PE3-CE24. In the steady
   mode PIT1 on PE1 and PE3 will contain information on links PE1-CE11,
   PE1-CE15 and PE2-CE13; PIT2 on PE1 and PE2 will contain entries for
   links PE1-CE22 and PE3-CE24. Thus, all PEs will learn about all
   remote PE-CE links for all L1VPNs supported by PEs.

   Note that P in this configuration does not have links connecting it
   to any of L1VPNs. It neither originates L1VPN LSAs nor maintains any
   PITs. However, it does participate in the flooding of all of the
   L1VPN LSA and hence `maintains the LSAs in its LSDB. This is a cause
   for scalability concerns and could prove to be problematic on large
   networks.


5. Backward compatibility

   Neither the TLV nor the LSA introduced in this document present any
   interoperability issues. OSPF speakers that do not support L1VPN
   auto-discovery application (Ps for example) just participate in the
   L1VPN LSAs flooding process but should ignore the LSAs contents.







Bryskin, Berger                                                 [Page 8]


Internet Draft draft-bryskin-l1vpn-ospf-auto-discovery-01.txt   April 2006


6. Security Considerations

   The solution 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, no new security issues are raised in this
   document.


7. Intellectual Property Statement

   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.

   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".










Bryskin, Berger                                                 [Page 9]


Internet Draft draft-bryskin-l1vpn-ospf-auto-discovery-01.txt   April 2006


8. Acknowledgement

   We would like to thank Adrian Farrel for his useful comments.


9. References

9.1. Normative References

   [RFC2119] Bradner, S., "Key words for use in RFCs to indicate
             requirements levels", RFC 2119, March 1997.

   [RFC2328] Moy, J., " OSPF Version 2 ", RFC 2328, April 1998.

   [RFC2370] Coltun, R., " The OSPF Opaque LSA Option ", RFC 2730,
             July 1998.

   [RFC3630] Ktaz, 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.

   [L1VPN-BM] Fedyk, D., Rekhter, Y. (Eds.), "Layer 1 VPN Basic
              Mode", draft-fedyk-l1vpn-basic-mode-01.txt, January
              2006, work in progress.


9.2. Informative References

   [L1VPN-FRMWK] Tomonori Takeda, et al., " Framework and
                 Requirements for Layer 1 Virtual Private Networks",
                 draft-ietf-l1vpn-framework-00.txt, August 2005, work
                 in progress

   [L1VPN-BGP] Ould-Brahim H.,  Fedyk D., Rekhter, Y., "BGP-based Auto-
               Discovery for L1VPNs ",
               draft-ouldbrahim-l1vpn-bgp-auto-discovery- 00.txt
                (work in progress)

   [LEXICOGRAPHY] Bryskin, I., Farrel, A "A Lexicography for the
                  Interpretation of Generalized Multiprotocol Label
                  Switching (GMPLS) Terminology within The Context of
                  the ITU-T's Automatically Switched Optical Network
                  (ASON) Architecture", (work in progress)




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10. Authors' Addresses

   Igor Bryskin
   Movaz Networks, Inc.
   7926 Jones Branch Drive
   Suite 615
   McLean, VA - 22102
   Email: ibryskin@movaz.com

   Lou Berger
   LabN Consulting, LLC
   Email: lberger@labn.net


11. Full 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.


12. 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



Bryskin, Berger                                                [Page 11]


Internet Draft draft-bryskin-l1vpn-ospf-auto-discovery-01.txt   April 2006


   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.















































Bryskin, Berger                                                [Page 12]

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