Internet Working Group                Don Fedyk(ed.), (Nortel)
   Internet Draft          Yakov Rekhter(ed.), (Juniper Networks)
                                  Dimitri Papadimitriou (Alcatel)
   Expiration Date: January 2008          Richard Rabbat (Google)
                                     Lou Berger (LabN Consulting)
   Intended Status: Standards Track                     July 2007


                         Layer 1 VPN Basic Mode
                    draft-ietf-l1vpn-basic-mode-02.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
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   This Internet-Draft will expire in January 2008.

Copyright Notice

   Copyright (C) The IETF Trust (2007).

Abstract

   This draft describes the basic mode of Layer 1 VPNs (L1VPN BM) that
   is port based VPNs. In L1VPN BM, the basic unit of service is a
   Label Switched Path (LSP) between a pair of customer ports within a
   given VPN port-topology. This draft defines the operational model
   using either provisioning or a VPN auto-discovery mechanism and the
   signaling extensions for the L1VPN BM.


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Internet Draft  draft-ietf-l1vpn-basic-mode-02.txt       July 2007

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].

   In addition, the reader is assumed to be familiar with the
   terminology defined and used in [RFC3945], [RFC3471], [RFC3473],
   [RFC3477], [RFC4201], [RFC4202], [RFC4204], [RFC4208] and
   referenced.

Table of Contents

1. Introduction.......................................................3
2. Layer 1 VPN Services...............................................4
3. Addressing, Ports, Links and Control Channels......................6
3.1 Service Provider Realm............................................6
3.2 Layer 1 Ports and Index...........................................6
3.3 Port and Index Mapping............................................7
4. Port Based L1VPN Basic Mode........................................9
4.1 L1VPN Port Information Tables....................................10
4.1.1. Local Auto-Discovery Information..............................11
4.1.2. PE Remote Auto-Discovery Information..........................11
4.2 CE to CE LSP Establishment.......................................13
4.3 Signaling........................................................13
4.3.1 Signaling Procedures...........................................14
4.3.1.1 Shuffling Sessions...........................................15
4.3.1.2 Stitched or Nested Sessions..................................16
4.3.1.3 Other Signaling..............................................16
4.4 Recovery Procedures..............................................17
5. Security Considerations...........................................17
6. IANA Considerations...............................................18
7. Intellectual Property Considerations..............................18
8. References........................................................18
8.1 Normative References.............................................18
8.2 Informative References...........................................19
9. Author's Addresses................................................19
10. Disclaimer of Validity...........................................20
11. Copyright Statement..............................................20














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1. Introduction


   This draft describes the basic mode of Layer 1 VPNs (L1VPN BM) that
   outlined in [L1VPN-FRAMEWORK]. In this document, we consider a
   service provider network that consists of devices that support GMPLS
   (e.g., Lambda Switch Capable devices, Optical Cross Connects, SDH
   Cross Connects, etc.). We partition these devices into P (provider)
   and PE (provider edge) devices. In the context of this document we
   will refer to the former devices as just "P", and to the latter
   devices as just "PE". The Ps are connected only to the devices
   within the provider's network. The PEs are connected to the other
   devices within the network (either Ps, or PEs), as well as to the
   devices outside of the services provider network. We'll refer to
   such other devices as Client Edge (CE) devices. An example of a CE
   would be a GMPLS-enabled device that is either a router, an SDH
   cross-connect, or an Ethernet switch.

   The [RFC4208] draft is the basis for signaling from the CE to the
   PE. In the [RFC4208] draft the terms Core Node (CN) and Edge Node
   (EN) correspond to PE and CE respectively.



                           +---+    +---+
                           | P |    | P |
                           +---+    +---+
                     PE   /              \  PE
                  +-----+               +-----+    +--+
                  |     |               |     |----|  |
          +--+    |     |               |     |    |CE|
          |CE|----+-----+               |     |----|  |
          +--+\      |                  |     |    +--+
               \  +-----+               |     |
                \ |     |               |     |    +--+
                 \|     |               |     |----|CE|
                  +-----+               +-----+    +--+
                         \              /
                         +---+    +---+
                         | P |....| P |
                         +---+    +---+

   Figure 1: Generalized Layer 1 VPN Reference Model

   This draft specifies how the L1VPN Basic Mode (BM) service can be
   realized using provisioning or VPN auto-discovery, Generalized
   Multi-Protocol Label Switching (GMPLS) Signaling
   [RFC3471],[RFC3473], Routing [RFC4202] and LMP [RFC4204] mechanisms.

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   The L1VPN auto-discovery has similar requirements [L1VPN-FRAMEWORK]
   to the L3VPNs auto-discovery. As with L3VPNs there are protocol
   options to be made with auto-discovery. Section 4.1.1 deals with the
   information need to be discovered. GMPLS routing and signaling are
   used without extensions within the services provider network to
   establish and maintain Lambda Switch Capable (LSC) or SONET/SDH
   (TDM) connections between service provider nodes. This follows the
   model in [RFC4208].

   In L1VPN BM, the use of LMP facilitates the population of the
   services provider port information tables. Indeed, LMP MAY be used
   as an option to automate local CE-PE link discovery. LMP also MAY
   augment routing in extended mode as well as failure handling
   capabilities.

2. Layer 1 VPN Services

   Layer 1 services on the interfaces of customer and services provider
   ports could be any of the L1 interfaces supported by GMPLS. Since
   the mechanisms specified here use GMPLS as the signaling mechanism,
   and since GMPLS applies to both SONET/SDH (TDM) and Lambda Switch
   Capable (LSC) interfaces, it results that L1VPN services includes
   but is not restricted to Lambda Switch Capable or TDM based
   equipment. Note that this document describes Basic Mode L1 VPNs and
   as such assumes that
   (1) GMPLS RSVP-TE is used for signaling both within the service
   provider (between PEs), as well as between the customer and the
   service provider (between CE and PE);
   (2) GMPLS Routing on the CE-PE link is outside the scope of the
   basic mode of operation of L1VPN see [L1VPN-FRAMEWORK].

   A CE is connected to a PE via one or more links. In the context of
   this document a link is a GMPLS Traffic Engineering (TE) link
   construct, as defined in [RFC4202]. In the context of this document,
   a TE link is a logical construct that is a member of a VPN hence
   introducing the notion of membership to a set of CEs forming the
   VPN. Interfaces at the end of each link are limited to type LSC or
   TDM interfaces that are supported by GMPLS. More specifically a
   [CE,PE] link MUST be of the type [X,LSC] or [Y,TDM] where X = PSC,
   L2SC, or TDM and Y = PSC or L2SC, in case the LSP is not terminated
   by the CE, X MAY also = LSC and Y = TDM (the latter case is outside
   the scope of this document). Likewise, PEs could be any L1 devices
   that are supported by GMPLS (e.g., optical cross connects, SDH
   cross-connects), while CEs MAY be devices at layers 1, 2 and 3 such
   as an SDH cross-connect, an Ethernet switch, and a router
   respectively).

   Each TE link MAY consist of one or more channels or sub-channels
   (e.g., wavelength or wavelength and timeslot respectively). For the
   purpose of this discussion we assume that all the channels within a
   given link have similar shared characteristics (e.g., switching
   capability, encoding, type, etc_), and can be selected independently

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   from the CE's point of view. Channels on different links of a CE
   need not have the same characteristics.

   There MAY be more than one TE link between a given CE-PE pair. A CE
   MAY be connected to more than one PE (with at least one port per
   each PE). And, conversely, a PE MAY have more than one CE from
   different VPNs connected to it.

   If a CE is connected to a PE via multiple TE links and all the links
   belong to the same VPN, for the purpose of this document,  these
   links (referred to as component links) MAY  be treated as a single
   TE link using the link bundling constructs [RFC4201].

   A link MAY have only data bearing channels, or only control bearing
   channels, or both.  For the purpose of this discussion it is
   REQUIRED that for a given CE-PE pair at least one of the links
   between them has at least one data bearing channel, and at least one
   control bearing channel, or there is IP reachability between the CE
   and the PE that could be used to exchange control information.

   A point-to-point link has two end-points - one on the CE and one on
   the PE. In the context of this document we'll refer to the former as
   "CE port", and to the latter as "PE port". From the above it follows
   that a CE is connected to a PE via one or more ports, where each
   port MAY consist of one or more channels or sub-channels (e.g.,
   wavelength or wavelength and timeslot respectively), and all the
   channels within a given port have shared similar characteristics and
   can be interchanged from the CE's point of view. Similar to the
   definition of a TE link, in the context of this document, ports are
   logical constructs that are used to represent a grouping of physical
   resources that are used to connect a CE to a PE on a per L1VPN
   basis.

   At any point in time, a given port on a PE is associated with at
   most one L1VPN, or to be more precise with at most one Port
   Information Table maintained by the PE (although different ports on
   a given PE could be associated with different L1VPNs, or to be more
   precise with different Port Information Tables). The association of
   a port with a VPN MAY be defined by provisioning the relationship on
   the services provider devices. In other words the context of a VPN
   membership in Basic mode is enforced through service provider
   control.

   This document assumes that the interface between the CE and PE used
   for the purpose of signaling is capable of initiating/processing
   GMPLS protocol messages [RFC3473] and follows the procedures
   described in [RFC4208].

   An important goal of L1VPN services is the ability to support what
   is known as "single ended provisioning", where the addition of a new
   port to a given L1VPN  involves configuration changes only on the PE


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   that has this port.  The extension of this model to the CE is
   outside the scope of the L1VPN BM.

   Another important goal in the L1VPN service is the ability to
   establish/terminate an LSP between a pair of (existing) ports within
   a L1VPN from the CE devices without involving configuration changes
   in any of the services provider's devices. In other words, the VPN
   topology is under the CE device control (provided that the
   underlying PE-PE connectivity is provided and allowed by the
   network).

   The mechanisms outlined in this document aim at achieving these
   above goals. Specifically, as part of the L1VPN service offering,
   these mechanisms (1) enable the service provider to restrict the set
   of ports to which a given port could be connected, (2) enable a CE to
   establish the actual LSP to a subset of ports. Finally, the
   mechanisms allow arbitrary L1VPN topologies to be supported ranging
   from hub-and-spoke to full mesh point to point connections. Other
   more advanced service and topology support such as point to multi
   point (P2MP) services etc. is for further study.

   The L1VPN BM mode does not specify the exchange of CE routing or
   topology information to the services provider.

3. Addressing, Ports, Links and Control Channels

   GMPLS established conventions for Addressing and link numbering are
   discussed in the [RFC3945] documents.  This section builds on those
   definitions for the L1VPN case where we now have Customer and
   services provider addresses in a Layer 1 Context.

3.1 Service Provider Realm

   This document assumes that a service provider, or a group of service
   providers that collectively offer L1VPN service, have a single
   addressing realm that spans all PE devices involved in providing the
   L1VPN service. This is necessary to enable GMPLS mechanisms for path
   establishment and maintenance. We will refer to this realm as the
   service provider addressing realm. This document further assumes
   that each L1VPN customer has its own addressing realm. We will refer
   to such realms as the customer addressing realms. Customer
   addressing realms MAY overlap with each other, and MAY also overlap
   with the service provider addressing realm.

3.2 Layer 1 Ports and Index

   Within a given L1VPN, each port on a CE that connects the CE to a PE
   has an identifier that is unique within that L1VPN (but need not be
   unique across several L1VPNs). One way to construct such an
   identifier is to assign each port an address that is unique within a
   given L1VPN, and use this address as a port identifier. Another way
   to construct such an identifier is to assign each port on a CE an
   index that is unique within that CE, assign each CE an address that
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   is unique within a given L1VPN, and then use a tuple <port index, CE
   address> as a port identifier. Note that both the port and the CE
   address MAY be an address in several formats.  This includes, but is
   not limited to IPv4, and IPv6. This identifier is part of the
   Customer Addressing Realm and is used by the CE device to identify
   the CE port and the CE remote port for signaling.  CEs do not know
   or understand the services provider Realm addresses.

   Within a service provider network, each port on a PE that connects
   that PE to a CE has an identifier that is unique within that
   network. One way to construct such an identifier is to assign each
   port on a PE an index that is unique within that PE, assign each PE
   an IP address that is unique within the service provider addressing
   realm, and then use a tuple <port index, PE IPv4 address> or <port
   index, PE IPv6 address> as a port identifier within the services
   provider network. Another way to construct such an identifier is to
   assign an IPv4 or IPv6 address that is unique within the service
   provider addressing realm to each such port. Either way, this IPv4
   or IPv6 address is internal to the service provider network and is
   used for GMPLS signaling within the service provider network.

   As a result, each link connecting the CE to the PE is associated
   with a CE port that has a unique identifier within a given L1VPN,
   and with a PE port that has a unique identifier within the service
   provider network. We'll refer to the former as the Customer Port
   Identifier (CPI), and to the latter as the Provider Port Identifier
   (PPI).

3.3 Port and Index Mapping

   This document assumes that each PE port that has a PPI also has an
   identifier that is unique within the L1VPN customer addressing realm
   of the L1VPN associated with that port.  One way to construct such
   an identifier is to assign each port an address that is unique
   within a given L1VPN customer addressing realm, and use this address
   as a port identifier. Another way to construct such an identifier is
   to assign each port an index that is unique within a given PE,
   assign each PE an IP address that is unique within a given L1VPN
   customer addressing realm (but need not be unique within the service
   provider network), and then use a tuple <port index, PE IP address>
   that acts as a port identifier.  We'll refer to such port identifier
   as the VPN-PPI.

   For L1VPNs it is a requirement that services provider operations are
   independent of the VPN customer's addressing realm and the services
   provider addressing realm is hidden from the customer. To achieve
   this we have created two identifiers at the PE, one customer facing
   and the other services provider facing. The PE IP address used for
   the VPN-PPI is independent of the PE IP address used for the PPI (as
   the two are taken from different address realms, the former from the
   services provider's addressing realm and the latter from a VPN
   customer's addressing realm). If for a given port on a PE, the PPI
   and the VPN-PPI port identifiers are unnumbered, then they both
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   could use exactly the same port index. This is a mere convenience
   since the PPI and VPN_PPI can be in any combination of valid
   formats.


                           (Client realm)
               +----+                             +----+
               |    |<Port Index>    <Port Index> |    |
               |    |CPI              VPN-PPI     |    |
            ---| CE |-----------------------------| PE |---
               |    |                <Port Index> |    |
               |    |                 PPI         |    |
               +----+                             +----+
                                     (Provider realm)


             Figure 2: Customer/Provider Port/Index Mapping

   Note, as stated earlier, that IP addresses used for the CPIs, PPIs
   and VPN-PPIs could be either IPv4, or IPv6 format addresses.

   For a given link connecting a CE to a PE, if the CPI is an IPv4/IPv6
   address, then the VPN-PPI has to be an IPv4/IPv6 address as well.
   And if the CPI is a <port index, CPI IPv4/IPv6 address>, then the
   VPN-PPI MUST be a <port index, PE IPv4/IPv6 address>. However, for a
   given port on PE, whether the VPN-PPI of that port is an IP address
   or a <port index, PE IPv4/IPv6 address> is independent of whether
   the PPI of that port is an IP address or a <port index, PE IPv4/IPv6
   address>.

   This document assumes that assignment of the PPIs is controlled
   solely by the service provider (without any coordination with the
   L1VPN customers), while assignment of addresses used by the CPIs and
   VPN-PPIs is controlled solely by the administrators of L1VPN. The
   L1VPN administrator is the entity that controls the L1VPN service
   specifics for the L1VPN customers. This function may be owned by the
   service provider but may also be performed by a third party who has
   agreements with the service provider. And, of course, each L1VPN
   could assign such addresses on its own, without any coordination
   with other L1VPNs.

   This document also assumes that there is an IP control channel
   between the CE and the PE. This channel could be either a single IP
   hop, or a tunnel (GRE or IP-in-IP) or an IP private network, or even
   an IP VPN for example. We'll refer to the CE's address of this
   channel as the CE Control Channel Address (CE-CC-Addr), and to the
   PE's address of this channel as the PE Control Channel Address (PE-
   CC-Addr). Both CE-CC-Addr and PE-CC-Addr are REQUIRED to be unique
   within the L1VPN they belong to, but are not REQUIRED to be unique
   across multiple L1VPNs. Control channel addresses are not shared
   amongst multiple VPNs. Assignment of CE-CC-Addr and PE-CC-Addr is
   controlled by the administrators of the L1VPN.

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   Multiple ports on a CE could share the same control channel only as
   long as all these ports belong to the same L1VPN. Likewise, multiple
   ports on a PE could share the same control channel only as long as
   all these ports belong to the same L1VPN.

4. Port Based L1VPN Basic Mode

   An L1VPN is a port-based VPN service where a pair of CEs could be
   connected through the service provider network via a GMPLS-based LSP
   within a given VPN port topology. It is precisely this LSP that
   forms the basic unit of the L1VPN service that the service provider
   network offers. If a port by which a CE is connected to a PE
   consists of multiple channels (e.g., multiple wavelengths), the CE
   could establish LSPs to multiple other CEs in the same VPN over this
   single port.

   In the L1VPN, the service provider does not initiate the creation of
   an LSP between a pair of PE ports. This is done rather by the CEs,
   which attach to the ports. However, the SP, by using the
   mechanisms/toolkit outlined in this document, restricts the set of
   other PE ports, which may be the remote endpoints of LSPs that have
   the given port as the local endpoint. Subject to these restrictions,
   the CE-to-CE connectivity is under the control of the CEs
   themselves. In other words, the SP allows a L1VPN to have a certain
   set of topologies (expressed as a port-to-port connectivity matrix;
   CE-initiated signaling is used to choose a particular topology from
   that set.

   For each L1VPN that has at least one port on a given PE, the PE
   maintains a Port Information Table (PIT) associated with that L1VPN.
   A PIT contains a list of <CPI, PPI> tuples for all the ports within
   its L1VPN. In addition, for local PE ports of a given L1VPN the
   tuples also include the VPN-PPIs of these ports.




















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                  PE                        PE
               +---------+             +--------------+
   +--------+  | +------+|             | +----------+ | +--------+
   |  VPN-A |  | |VPN-A ||             | |  VPN-A   | | |  VPN-A |
   |   CE1  |--| |PIT   ||    Route    | |  PIT     | |-|   CE2  |
   +--------+  | |      ||<----------->| |          | | +--------+
               | +------+|Dissemination| +----------+ |
               |         |             |              |
   +--------+  | +------+|             | +----------+ | +--------+
   | 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 3 Basic Mode L1VPN Service

4.1 L1VPN Port Information Tables


   A PIT consists of local information as well as remote information.
   It follows that PIT on a given PE is populated from two information
   sources:

     1. The information related to the CEs' ports attached to the ports
        local to that PE.
     2. The information about the CEs connected to the remote PEs

   A PIT MAY be populated via provisioning or by auto-discovery
   procedures. When provisioning is used the entire table MAY be
   populated by provisioning commands either at a console or by a
   management system which may have some automation capability.
   As the network grows some form of automation is desirable.

   For local information between a CE and a PE, a PE MAY leverage LMP
   to populate the <CPI, VPN-PPI> link information. This local
   information also needs to be propagated to other PEs that share the
   same VPN. The mechanisms for this are out of scope for this document
   but the information needed to be exchanged is described in section
   4.1.1.

   The PIT is by nature VPN-specific in that entries for a L1VPN are
   only REQUIRED on a PE if that PE locally supports that L1VPN by
   having CEs belonging to that VPN attached to the PE. However, the
   full set of PITs with all L1VPN entries for multiple VPNs MAY also
   be available to all PEs.

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   The remote information in the context of a VPN identifier ie the
   remote CEs of this VPN could also be sent to the local CE belonging
   to the same VPN. Exchange of this information is outside the scope
   of this document.

4.1.1. Local Auto-Discovery Information

   The information that needs to be discovered on a PE local port is
   the remote CPI and the VPN-PPI.  In many cases if LMP is used
   between the CE and PE, LMP can exchange this information. Other
   mechanism MAY also be used but discussion of these mechanisms is
   outside the scope of this document.

   Once a CPI has been discovered, the corresponding VPN-PPI maps in a
   local context to a VPN Identifier and a corresponding PPI.
   One way to enforce a provider controlled VPN context is to pre-
   provision VPN-PPI's with a VPN identifier. Other policy mechanisms
   to achieve this are outside the scope of this document.  In this
   manner, a relationship of a CPI to a VPN and PPI port can be
   established when the port is provisioned as belonging to the VPN.



4.1.2. PE Remote Auto-Discovery Information


   This section provides the information that is carried by any auto-
   discovery mechanism, and is used to dynamically populate a PIT. The
   information provides a single <CPI, PPI> mapping.  Each auto-
   discovery mechanism will define the method(s) by which multiple
   <CPI, PPI> mappings are communicated, as well as invalidated.

   The encoding of the auto-discovery information uses BGP address
   family identifiers (AFIs), and defines a new AFI for L1VPN (to be
   assigned by the IANA). This information should be consistent
   regardless of the mechanism use to distribute the information.
   [L1VPN-BGP-AD], [L1VPN-OSPF-AD].

   The format of encoding a single <PPI, CPI> tuple is:

        +---------------------------------------+
        |     Length (1 octet)                  |
        +---------------------------------------+
        |     PPI Length (1 octet)              |
        +---------------------------------------+
        |     PPI (variable)                    |
        +---------------------------------------+
        |     CPI AFI (2 octets)                |
        +---------------------------------------+
        |     CPI (length)                      |
        +---------------------------------------+
        |     CPI (variable)                    |
        +---------------------------------------+
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        Figure 4: Auto-Discovery Information

   The use and meaning of these fields are as follows:

   Length:

      A one octet field whose value indicates the length of the  <PPI,
      CPI> Information tuple in octets.

   PPI Length:

      A one octet field whose value indicates the length of the PPI
      field

   PPI field:

      A variable length field that contains the value of the PPI
      (either an address or <port index, address> tuple


   CPI AFI field:

      A two octets field whose value indicates address family of the
      CPI.

   CPI Length:

      A once octet field whose value indicates the length of the CPI
      field.

   CPI (variable):

      A variable length field that contains the CPI value (either an
      address or <port index, address> tuple.


   <PPI, CPI> tuples MUST also be associated with one or more globally
   unique identifiers associated with a particular VPN.  A globally
   unique identifier can encode a VPN-ID, a route target, or any other
   globally unique identifier. In this document we specify a generic
   encoding format for the globally unique identifier common to all the
   auto-discovery mechanisms. However, each auto-discovery mechanism
   will define the specific method(s) by which the encoding is
   distributed and the association with a <PPI, CPI> tuple is made.
   The encoding of the globally unique identifier associated with the
   VPN is:

            +------------------------------------------------+
            |  L1vpn Globally unique identifier  (8 octets)  |
            +------------------------------------------------+

       Figure 5: Auto-Discovery Globally unique identifier Format
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4.2 CE to CE LSP Establishment

   In order to establish an LSP, a CE needs to identify all other CEs
   in the CE's L1VPN it wants to connect to. A CE may already have
   obtained this information through provisioning or through some other
   schemes (such schemes are outside the scope of this document).

   Ports associated with a given CE-PE link, in addition to their CPI
   and PPI MAY also have other information associated with them that
   describes characteristics and constraints of the channels within
   these ports, such as encoding supported by the channels, bandwidth
   of a channel, total unreserved bandwidth within the port, etc. This
   information could be further augmented with the information about
   certain capabilities of the services provider network (e.g., support
   RSOH DCC transparency, arbitrary concatenation, etc.). This
   information is used to ensure that ports at each end of an LSP have
   compatible characteristics, and that there are sufficient
   unallocated resources to establish an LSP between these ports.

   It may happen that for a given pair of ports within an L1VPN, each
   of the CEs connected to these ports would concurrently try to
   establish an LSP to the other CE. If having a pair of LSPs between a
   pair of ports is viewed as undesirable, the way to resolve this is
   to require the CE with the lower value of the CPI to terminate the
   LSP originated by the CE. This option could be controlled by
   configuration on the CE devices.

4.3 Signaling

   In L1VPN BM a CE needs to be configured with the CPIs of other
   ports. Once a CE is configured with the CPIs of the other ports
   within the same L1VPN, which we'll refer to as "target ports", the
   CE uses a (subset of) GMPLS signaling, to request the provider
   network to establish an LSP to a target port.

   For inter-CE connectivity, the request originated by the CE contains
   the CPI of the port on the CE that CE wants to use for the LSP, and
   the CPI of the target port. When the PE attached to the CE that
   originated the request receives the request, the PE identifies the
   appropriate PIT, and then uses the information in that PIT to find
   out the PPI associated with the CPI of the target port carried in
   the request. The PPI should be sufficient for the PE to establish an
   LSP. Ultimately the request reaches the CE associated with the
   target CPI (note that the request still carries the CPI of the CE
   that originated the request). If the CE associated with the target
   CPI accepts the request, the LSP is established.

   Note that a CE need not establish an LSP to every target port that
   CE knows about - it is a local CE matter to select a subset of
   target ports to which the CE will try to establish LSPs.

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   The procedures for establishing an individual connection between two
   corresponding CEs is the same as the procedure specified for GMPLS
   overlay [RFC4208].

4.3.1 Signaling Procedures

   When an ingress CE sends an RSVP Path message to an ingress PE, the
   source IP address in the IP packet that carries the message is set
   to the appropriate CE-CC-Addr, and the destination IP address in the
   packet is set to the appropriate PE-CC-Addr. When the ingress PE
   sends back to the ingress CE the corresponding Resv message, the
   source IP address in the IP packet that carries the message is set
   to the PE-CC-Addr, and the destination IP address is set to the CE-
   CC-Addr.

   Likewise, when an egress PE sends an RSVP Path message to an egress
   CE, the source IP address in the IP packet that carries the message
   is set to the appropriate PE-CC-Addr, and the destination IP address
   in the packet is set to the appropriate CE-CC-Addr. When the egress
   CE sends back to the egress PE the corresponding Resv message, the
   source IP address in the IP packet that carries the message is set
   to the CE-CC-Addr, and the destination IP address is set to the PE-
   CC-Addr.

   In addition to being used for IP addresses in the IP packet that
   carries RSVP messages between CE and PE, CE-CC-Addr and PE-CC-Addr
   are also used in the Next/Previous Hop Address field of the IF_ID
   RSVP_HOP object that is carried between CEs and PEs.

   In the case where a link between CE and PE is a numbered non-bundled
   link, the CPI and VPN-PPI of that link are used for the Type 1 or 2
   TLVs of the IF_ID RSVP HOP object that is carried between the CE and
   PE. In the case where a link between CE and PE is an unnumbered non-
   bundled link, the CPI and VPN-PPI of that link are used for the IP
   Address field of the Type 3 TLV. In the case where a link between CE
   and PE is a bundled link, the CPI and VPN-PPI of that link are used
   for the IP Address field of the Type 3 TLVs.

   Additional processing related to unnumbered links is described in
   the"Processing the IF_ID RSVP_HOP object"/"Processing the IF_ID
   TLV",and "Unnumbered Forwarding Adjacencies" sections of RFC 3477
   [RFC3477].

   When an ingress CE originates a Path message to establish an LSP
   from a particular port on that CE to a particular target port, the
   CE uses the CPI of its port in the Sender Template object. If the
   CPI of the target port is an IP address, then the CE uses it in the
   Session object. And if the CPI of the target port is a <port index,
   IP address> tuple, then the CE uses the IP address part of the tuple
   in the Session object, and the whole tuple as the Unnumbered
   Interface ID subobject in the ERO.


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   There are two options for RSVP-TE sessions. One option is to have a
   single RSVP-TE session end to end where the addresses of the
   customer and the provider are swapped at the PE, termed shuffling.
   The other options is when stitching or hierarchy is used to create
   two LSP sessions, one between the provider PE(s) and another end to
   end session between the CEs.

4.3.1.1 Shuffling Sessions

   Shuffling sessions are used when the desire is to have a single LSP
   originating at the CE and terminating at the far end CE. The
   customer addresses are shuffled to provider addresses at the ingress
   PE and back to customer addresses at the egress PE by using the
   mapping provided by the PIT.

   When the Path message arrives at the ingress PE, the PE selects the
   PIT associated with the L1VPN, and then uses this PIT to map CPIs
   carried in the Session and the Sender Template objects to the
   appropriate PPIs. Once the mapping is done, the ingress PE replaces
   CPIs with these PPIs. As a result, the Session and the Sender
   Template objects that are carried in the GMPLS signaling within the
   service provider network carry PPIs, and not CPIs. The egress PE
   performs the reverse mapping - it maps PPIs carried in the Session
   and the Sender Template object into the appropriate CPIs, and then
   sends the Path message to the egress CE that has the target port.
   This translation of addresses and session ids is termed shuffling
   and driven by the L1VPN Port information tables. This MUST be
   performed for all RSVP-TE Messages at the PE edges.  In this case
   there is one CE to CE session.

   At the egress PE, the reverse mapping operation is performed. The PE
   extracts the ingress/egress PPI values carried in the
   SENDER_TEMPLATE and SESSION objects (respectively). The egress PE
   identifies the appropriate PIT to find out the appropriate CPI
   associated with the PPI of the egress CE. Once the mapping is
   retrieved, the egress PE replaces the ingress/egress PPI values with
   the corresponding CPI values. As a result, the SESSION and the
   SENDER_TEMPLATE objects included in the GMPLS RSVP-TE Path message
   sent from the egress PE to the egress CE carry CPIs, and not PPIs.
   Here also, for the GMPLS RSVP-TE Path messages sent from the egress
   PE to CE, the source IP address (of the IP packet carrying this
   message) is set to the appropriate PE-CC-Addr, and the destination
   IP address (of the IP packet carrying this message) is set to the
   appropriate CE-CC-Addr.

   At this point the CE's view is a single LSP point to point between
   the two CEs with a virtual link between the PE nodes.  CE-PE(-)PE-
   CE.  The L1VPN PE nodes have a view of the PE-PE LSP in all its
   detail.  The PEs MAY filter the RSVP-TE signaling removing
   information about the provider topology and replacing it with a view
   of a virtual link.


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4.3.1.2 Stitched or Nested Sessions

   Stitching or Nesting options are dependent on the LSP switching
   types. If the CE to CE and PE to PE LSPs are identical in switching
   type and capacity the LSP MAY be stitched together and the
   procedures in [GMPLS-STITCHING] apply. If the CE to CE LSPs and the
   PE to PE LSPs are of not the same switching type or of different but
   compatible capacity the LSPs MAY be Nested and the procedures for
   [RFC4206] apply.  The Stitched and Nested LSP signaling are
   analogous procedures and can be discussed together.

   When the Path Message arrives at the ingress PE, the PE selects the
   PIT associated with the L1VPN, and then uses this PIT to map CPIs
   carried in the Session and the Sender Template objects to the
   appropriate PPIs. Once the mapping is done, a new PE to PE session
   is established with the parameters compatible with the CE session.
   Upon successful establishment of the PE to PE session, the CE
   signaling request is sent to the egress PE.

   At the ingress PE when stitching and nesting are used a PE to PE
   session is established. This could be achieved by several means:
     - Associating an already established PE-PE FA-LSP to the
      destination that meets the requested parameters.
     - Establishing a compliant PE-PE LSP.

   At this point the CE's view is a single LSP point to point between
   the two CEs with a virtual node the PE nodes.  CE-PE(-)PE-CE.  The
   L1VPN PE nodes have a view of the PE-PE LSP in all its detail.  The
   PEs do not have filter the RSVP-TE signaling removing information
   about the provider topology because the PE-PE signaling is not
   visible to the CE nodes.

4.3.1.3 Other Signaling

   An ingress PE may receive and potentially reject a Path message that
   contains an Explicit Route Object and so cause the switched
   connection setup to fail. However, the ingress PE may accept EROs,
   which include a sequence of [<ingress PE (strict), egress CE CPI
   (loose)>].

   - Path message without ERO: when an ingress PE receives a Path
   message from an ingress CE that contains no ERO, it MUST calculate a
   route to the destination for the PE-to-PE LSP and include that route
   in an ERO, before forwarding the Path message. One exception would
   be if the egress core node were also adjacent to this core node.

   - Path message with ERO: when an ingress PE receives a Path message
   from an ingress CE that contains an ERO (of the form detailed
   above), the former computes a path to reach the egress PE. It then
   inserts this path as part of the ERO before forwarding the Path
   message.


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   In the case of Shuffling the overlay rules for Notification and RRO
   Processing are identical to the UNI or Overlay Model[RFC4208] which
   state that Edge PE MAY remove/edit Provider Notification and RRO
   objects when passing the messages to the CEs.


4.4 Recovery Procedures

   Signaling:

   A CE requests network protected (from PE-to-PE) LSP by using
   [RFC4873] technique. Dynamic identification of merge nodes is
   supported via the LSP Segment Recovery Flags carried in the
   Protection object (see Section 6.2 of [RFC4873]).

   Notification:

   A Notify Request object MAY be inserted in Path or Resv messages to
   indicate the address of a CE that should be notified of an LSP
   failure.  Notifications MAY be requested in both the upstream and
   downstream directions:

   o) Upstream notification is indicated via the inclusion of a Notify
   Request Object in the corresponding Path message.

   o) Downstream notification is indicated via the inclusion of a
   Notify Request Object in the corresponding Resv message.

   A PE receiving a message containing a Notify Request object SHOULD
   store the Notify Node Address in the corresponding state block. The
   PE SHOULD also include a Notify Request object in the outgoing Path
   or Resv message.  The outgoing Notify Node Address MAY be updated
   based on local policy.  This means that a PE upon reception of this
   object from the CE MAY update its value.

   If the ingress CE includes a NOTIFY_REQUEST object into the Path
   message, the ingress PE MAY replace the received 'IPv4 Notify Node
   Address' by its own selected 'IPv4 Notify Node Address', and in
   particular the local TE Router_ID. The Notify Request Object MAY be
   carried in Path or Resv messages (Section 7 of [RFC3473]). The
   format of the NOTIFY_REQUEST object is defined in [RFC3473].

   Inclusion of a NOTIFY_REQUEST object is used to request the
   generation of notifications upon failure occurrence but does not
   guarantee that a Notify message will be generated.



5. Security Considerations

   Since association of a particular port with a particular L1VPN (or
   to be more precise with a particular PIT) is done by the service
   provider as part of the service provisioning process (and thus can't
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   be altered via signaling between CE and PE), and since signaling
   between CE and PE is assumed to be over a private network (and thus
   can't be spoofed by entities outside the private network), the
   solution described in this document doesn't require authentication
   in signaling.


6. IANA Considerations

   This document makes no requests for IANA action.

7. Intellectual Property Considerations

   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.


8. References

8.1 Normative References

   [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
      Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC4208] Swallow, G., et al., "Generalized Multiprotocol Label
      Switching(GMPLS)User-Network Interface (UNI): Resource
      ReserVation Protocol-Traffic Engineering (RSVP-TE) Support
      for the Overlay Model", RFC 4208, October 2005.

   [GMPLS-STITCHING] A. Ayyangar, Ed., J.P. Vasseur, A. Farrel, "Label
      Switched Path Stitching with Generalized MPLS Traffic
      Engineering", work in progress.


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   [RFC4206] Kompella, K. and Y. Rekhter, "Label Switched Paths (LSP)
      Hierarchy with Generalized Multi-Protocol Label Switching
      (GMPLS)Traffic Engineering (TE)", RFC 4206, October 2005.

   [L1VPN-FRAMEWORK] Takeda, T (editor), "Framework and Requirements
      for Layer 1 Virtual Private Networks", work in progress.

   [RFC4873] Berger, L., Bryskin, I., Papadimitriou, D. Farrel, A.,
      "GMPLS Based Segment Recovery", RFC 4873, May 2007.

   [RFC3477] Kompella, K. and Y. Rekhter, "Signalling Unnumbered
      Links in Resource ReSerVation Protocol - Traffic Engineering
      (RSVP-TE)", RFC 3477, January 2003.


8.2 Informative References

   [RFC3471] Berger, L. (editor), "Generalized MPLS -Signaling
      Functional Description", January 2003, RFC3471.

   [RFC3473] Berger, L. (editor), "Generalized MPLS Signaling - RSVP-TE
      Extensions", RFC3473, January 2003.

   [RFC4202] Kompella, K., Rekhter, Y., "Routing Extensions in Support
      of Generalized Multi-Protocol Label Switching (GMPLS)", RFC 4202,
      October 2005.


   [RFC3945] E. Mannie (editor), "Generalized Multi-Protocol Label
      Switching (GMPLS) Architecture" RFC3945, October 2004

   [RFC4201] Kompella, K., Rekhter, Y., Berger, L., "Link Bundling in
      MPLS Traffic Engineering (TE)", RFC 4201, October 2005.

   [RFC4204] J. Lang (editor), "Link Management Protocol (LMP)," RFC
      4204, October 2005.

   [L1VPN-BGP-AD] Ould-Brahim, H., Fedyk, D., Rekhter, Y., "BGP-based
      Auto-Discovery for L1VPNs", work in progress.

   [L1VPN-OSPF-AD] Bryskin, I., Berger, Lou "OSPF Based L1VPN Auto-
      Discovery", work in progress.


9. Acknowledgments

   The authors would like to thank Adrian Farrel, Hamid Ould-Brahim and
   Tomonori Takeda for their valuable comments.

9. Author's Addresses


   Don Fedyk
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Internet Draft  draft-ietf-l1vpn-basic-mode-02.txt       July 2007

   Nortel Networks
   600 Technology Park
   Billerica, Massachusetts
   01821 U.S.A
   Phone: +1 (978) 288 3041
   Email: dwfedyk@nortel.com

   Yakov Rekhter
   Juniper Networks
   1194 N. Mathilda Avenue
   Sunnyvale, CA 94089
   Email: yakov@juniper.net

   Dimitri Papadimitriou (Alcatel)
   Fr. Wellesplein 1,
   B-2018 Antwerpen, Belgium
   Phone: +32 3 240-8491
   Email: dimitri.papadimitriou@alcatel.be

   Richard Rabbat
   Google, Inc
   1600 Amphitheater Pkwy
   Mountain View, CA 95054
   Email: rabbat@alum.mit.edu

   Lou Berger
   LabN Consulting, LLC
   Phone:  +1 301-468-9228
   EMail:  lberger@labn.net


10. Disclaimer of Validity

   "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, 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. Copyright Statement

   Copyright (C) The IETF Trust (2007).

   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.

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