draft-ietf-l2vpn-signaling-02.txt   draft-ietf-l2vpn-signaling-03.txt 
Network Working Group Eric C. Rosen Network Working Group E. Rosen
Internet Draft Wei Luo Internet-Draft W. Luo
Expiration Date: March 2005 Cisco Systems, Inc. Expires: August 23, 2005 B. Davie
Cisco Systems, Inc.
Vasile Radoaca V. Radoaca
Nortel Networks Nortel Networks
February 19, 2005
September 2004
Provisioning Models and Endpoint Identifiers in L2VPN Signaling Provisioning Models and Endpoint Identifiers in L2VPN Signaling
draft-ietf-l2vpn-signaling-03.txt
draft-ietf-l2vpn-signaling-02.txt
Status of this Memo Status of this Memo
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Copyright (C) The Internet Society (2005).
Abstract Abstract
There are a number of different kinds of "Provider Provisioned Layer There are a number of different kinds of "Provider Provisioned Layer
2 VPNs" (L2VPNs). The different kinds of L2VPN may have different 2 VPNs" (L2VPNs). The different kinds of L2VPN may have different
"provisioning models", i.e., different models for what information "provisioning models", i.e., different models for what information
needs to be configured in what entities. Once configured, the needs to be configured in what entities. Once configured, the
provisioning information is distributed by a "discovery process". provisioning information is distributed by a "discovery process".
When the discovery process is complete, a signaling protocol is When the discovery process is complete, a signaling protocol is
automatically invoked. The signaling protocol sets up the mesh of automatically invoked. The signaling protocol sets up the mesh of
Pseudowires (PWs) that form the (virtual) backbone of the L2VPN. Any Pseudowires (PWs) that form the (virtual) backbone of the L2VPN. Any
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This document specifies a number of L2VPN provisioning models, and This document specifies a number of L2VPN provisioning models, and
further specifies the semantic structure of the endpoint identifiers further specifies the semantic structure of the endpoint identifiers
required by each provisioning model. It discusses the way in which required by each provisioning model. It discusses the way in which
the endpoint identifiers are distributed by the discovery process, the endpoint identifiers are distributed by the discovery process,
especially when the discovery process is based upon the Border especially when the discovery process is based upon the Border
Gateway Protocol (BGP). It then specifies how the endpoint Gateway Protocol (BGP). It then specifies how the endpoint
identifiers are carried in the two signaling protocols that are used identifiers are carried in the two signaling protocols that are used
to set up PWs, the Label Distribution Protocol (LDP) and the Layer 2 to set up PWs, the Label Distribution Protocol (LDP) and the Layer 2
Tunneling Protocol (L2TPv3). Tunneling Protocol (L2TPv3).
Contents Table of Contents
1 Introduction ......................................... 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2 Signaling Protocol Framework ......................... 5
2.1 Endpoint Identification .............................. 5 2. Signaling Protocol Framework . . . . . . . . . . . . . . . . . 6
2.2 Creating a Single Bidirectional Pseudowire ........... 6 2.1 Endpoint Identification . . . . . . . . . . . . . . . . . 6
2.3 Attachment Identifiers and Forwarders ................ 7 2.2 Creating a Single Bidirectional Pseudowire . . . . . . . . 7
3 Applications ......................................... 8 2.3 Attachment Identifiers and Forwarders . . . . . . . . . . 8
3.1 Individual Point-to-Point VCs ........................ 9
3.1.1 Provisioning Models .................................. 9 3. Applications . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.1.1.1 Double Sided Provisioning ............................ 9 3.1 Individual Point-to-Point VCs . . . . . . . . . . . . . . 10
3.1.1.2 Single Sided Provisioning with Discovery ............. 9 3.1.1 Provisioning Models . . . . . . . . . . . . . . . . . 10
3.1.2 Signaling ............................................ 10 3.1.1.1 Double Sided Provisioning . . . . . . . . . . . . 10
3.2 Virtual Private LAN Service .......................... 11 3.1.1.2 Single Sided Provisioning with Discovery . . . . . 10
3.2.1 Provisioning ......................................... 11 3.1.2 Signaling . . . . . . . . . . . . . . . . . . . . . . 11
3.2.2 Auto-Discovery ....................................... 11 3.2 Virtual Private LAN Service . . . . . . . . . . . . . . . 12
3.2.2.1 BGP-based auto-discovery ............................. 11 3.2.1 Provisioning . . . . . . . . . . . . . . . . . . . . . 12
3.2.3 Signaling ............................................ 13 3.2.2 Auto-Discovery . . . . . . . . . . . . . . . . . . . . 12
3.2.4 Pseudowires as VPLS Attachment Circuits .............. 13 3.2.2.1 BGP-based auto-discovery . . . . . . . . . . . . . 12
3.3 Colored Pools: Full Mesh of Point-to-Point VCs ....... 13 3.2.3 Signaling . . . . . . . . . . . . . . . . . . . . . . 14
3.3.1 Provisioning ......................................... 13 3.2.4 Pseudowires as VPLS Attachment Circuits . . . . . . . 14
3.3.2 Auto-Discovery ....................................... 14 3.3 Colored Pools: Full Mesh of Point-to-Point VCs . . . . . . 14
3.3.2.1 BGP-based auto-discovery ............................. 14 3.3.1 Provisioning . . . . . . . . . . . . . . . . . . . . . 15
3.3.3 Signaling ............................................ 15 3.3.2 Auto-Discovery . . . . . . . . . . . . . . . . . . . . 15
3.4 Colored Pools: Partial Mesh .......................... 16 3.3.2.1 BGP-based auto-discovery . . . . . . . . . . . . . 15
3.5 Distributed VPLS ..................................... 16 3.3.3 Signaling . . . . . . . . . . . . . . . . . . . . . . 16
3.5.1 Signaling ............................................ 18 3.4 Colored Pools: Partial Mesh . . . . . . . . . . . . . . . 17
3.5.2 Provisioning and Discovery ........................... 19 3.5 Distributed VPLS . . . . . . . . . . . . . . . . . . . . . 17
3.5.3 Non-distributed VPLS as a sub-case ................... 20 3.5.1 Signaling . . . . . . . . . . . . . . . . . . . . . . 18
3.5.4 Inter-Provider Application of Dist. VPLS Signaling ... 20 3.5.2 Provisioning and Discovery . . . . . . . . . . . . . . 20
3.5.5 Splicing and the Data Plane .......................... 21 3.5.3 Non-distributed VPLS as a sub-case . . . . . . . . . . 20
4 Security Considerations .............................. 22 3.5.4 Splicing and the Data Plane . . . . . . . . . . . . . 21
5 Acknowledgments ...................................... 22
6 References ........................................... 22 4. Inter-AS Operation . . . . . . . . . . . . . . . . . . . . . . 22
7 Author's Information ................................. 23 4.1 Multihop EBGP redistribution of L2VPN NLRIs . . . . . . . 22
8 Intellectual Property Statement ...................... 24 4.2 EBGP redistribution of L2VPN NLRIs with Pseudowire
9 Full Copyright Statement ............................. 24 Switching . . . . . . . . . . . . . . . . . . . . . . . . 22
4.3 Inter-Provider Application of Dist. VPLS Signaling . . . . 23
5. Security Considerations . . . . . . . . . . . . . . . . . . . 25
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 26
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 28
Intellectual Property and Copyright Statements . . . . . . . . 29
1. Introduction 1. Introduction
[L2VPN-FW] describes a number of different ways in which sets of [L2VPN-FW] describes a number of different ways in which sets of
pseudowires may be combined together into "Provider Provisioned Layer pseudowires may be combined together into "Provider Provisioned Layer
2 VPNs" (L2 PPVPNs, or L2VPNs), resulting in a number of different 2 VPNs" (L2 PPVPNs, or L2VPNs), resulting in a number of different
kinds of L2VPN. Different kinds of L2VPN may have different kinds of L2VPN. Different kinds of L2VPN may have different
"provisioning models", i.e., different models for what information "provisioning models", i.e., different models for what information
needs to be configured in what entities. Once configured, the needs to be configured in what entities. Once configured, the
provisioning information is distributed by a "discovery process", and provisioning information is distributed by a "discovery process", and
once the information is discovered, the signaling protocol is once the information is discovered, the signaling protocol is
automatically invoked to set up the required pseudowires. The automatically invoked to set up the required pseudowires. The
semantics of the endpoint identifiers which the signaling protocol semantics of the endpoint identifiers which the signaling protocol
uses for a particular type of L2VPN are determined by the uses for a particular type of L2VPN are determined by the
provisioning model. That is, different kinds of L2VPN, with different provisioning model. That is, different kinds of L2VPN, with
provisioning models, require different kinds of endpoint identifiers. different provisioning models, require different kinds of endpoint
This document specifies a number of PPVPN provisioning models, and identifiers. This document specifies a number of PPVPN provisioning
specifies the semantic structure of the endpoint identifiers required models, and specifies the semantic structure of the endpoint
for each provisioning model. identifiers required for each provisioning model.
Either LDP (as specified in [LDP] and extended in [PWE3-CONTROL]) or Either LDP (as specified in [LDP] and extended in [PWE3-CONTROL]) or
L2TP version 3 (as specified in [L2TP-BASE] and extended in [L2TP- L2TP version 3 (as specified in [L2TP-BASE] and extended in
L2VPN] can be used as signaling protocols to set up and maintain [L2TP-L2VPN]) can be used as signaling protocols to set up and
pseudowires (PWs) [PWE3-ARCH]. Any protocol which sets up connections maintain pseudowires (PWs) [PWE3-ARCH]. Any protocol which sets up
must provide a way for each endpoint of the connection to identify connections must provide a way for each endpoint of the connection to
the other; each PW signaling protocol thus provides a way to identify identify the other; each PW signaling protocol thus provides a way to
the PW endpoints. Since each signaling protocol needs to support identify the PW endpoints. Since each signaling protocol needs to
all the different kinds of L2VPN and provisioning models, the support all the different kinds of L2VPN and provisioning models, the
signaling protocol must have a very general way of representing signaling protocol must have a very general way of representing
endpoint identifiers, and it is necessary to specify rules for endpoint identifiers, and it is necessary to specify rules for
encoding each particular kind of endpoint identifier into the encoding each particular kind of endpoint identifier into the
relevant fields of each signaling protocol. This document specifies relevant fields of each signaling protocol. This document specifies
how to encode the endpoint identifiers of each provisioning model how to encode the endpoint identifiers of each provisioning model
into the LDP and L2TPv3 signaling protocols. into the LDP and L2TPv3 signaling protocols.
We make free use of terminology from [L2VPN-FW], [L2VPN-TERM], and We make free use of terminology from [L2VPN-FW], [L2VPN-TERM], and
[PWE3-ARCH], in particular the terms "Attachment Circuit", [PWE3-ARCH], in particular the terms "Attachment Circuit",
"pseudowire", "PE", "CE". "pseudowire", "PE", "CE".
Section 2 provides an overview of the relevant aspects of [PWE3- Section 2 provides an overview of the relevant aspects of
CONTROL] and [L2TP-L2VPN]. [PWE3-CONTROL] and [L2TP-L2VPN].
Section 3 details various provisioning models and relates them to the Section 3 details various provisioning models and relates them to the
signaling process and to the discovery process. signaling process and to the discovery process.
Section 4 explains how the procedures for discovery and signaling can
be applied in a multi-AS environment and outlines several options for
the establishment of multi-AS L2VPNs.
We do not specify an auto-discovery procedure in this draft, but we We do not specify an auto-discovery procedure in this draft, but we
do specify the information which needs to be obtained via auto- do specify the information which needs to be obtained via
discovery in order for the signaling procedures to begin. The way in auto-discovery in order for the signaling procedures to begin. The
which the signaling mechanisms can be integrated with BGP-based way in which the signaling mechanisms can be integrated with
auto-discovery is covered in some detail. BGP-based auto-discovery is covered in some detail.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 document are to be interpreted as described in RFC 2119
2. Signaling Protocol Framework 2. Signaling Protocol Framework
2.1. Endpoint Identification 2.1 Endpoint Identification
Per [L2VPN-FW], a pseudowire can be thought of as a relationship Per [L2VPN-FW], a pseudowire can be thought of as a relationship
between a pair of "Forwarders". In simple instances of VPWS, a between a pair of "Forwarders". In simple instances of VPWS, a
Forwarder binds a pseudowire to a single Attachment Circuit, such Forwarder binds a pseudowire to a single Attachment Circuit, such
that frames received on the one are sent on the other, and vice that frames received on the one are sent on the other, and vice
versa. In VPLS, a Forwarder binds a set of pseudowires to a set of versa. In VPLS, a Forwarder binds a set of pseudowires to a set of
Attachment Circuits; when a frame is received from any member of that Attachment Circuits; when a frame is received from any member of that
set, a MAC address table is consulted (and various 802.1d procedures set, a MAC address table is consulted (and various 802.1d procedures
executed) to determine the member or members of that set on which the executed) to determine the member or members of that set on which the
frame is to be transmitted. In more complex scenarios, Forwarders frame is to be transmitted. In more complex scenarios, Forwarders
may bind PWs to PWs, thereby "splicing" two PWs together; this is may bind PWs to PWs, thereby "splicing" two PWs together; this is
needed, e.g., to support distributed VPLS. needed, e.g., to support distributed VPLS and some inter-AS
scenarios.
In simple VPWS, where a Forwarder binds exactly one PW to exactly one In simple VPWS, where a Forwarder binds exactly one PW to exactly one
Attachment Circuit, a Forwarder can be identified by identifying its Attachment Circuit, a Forwarder can be identified by identifying its
Attachment Circuit. In simple VPLS, a Forwarder can be identified by Attachment Circuit. In simple VPLS, a Forwarder can be identified by
identifying its PE device and its VPN. identifying its PE device and its VPN.
To set up a PW between a pair of Forwarders, the signaling protocol To set up a PW between a pair of Forwarders, the signaling protocol
must allow the Forwarder at one endpoint to identify the Forwarder at must allow the Forwarder at one endpoint to identify the Forwarder at
the other. In [PWE3-CONTROL], the term "Attachment Identifier", or the other. In [PWE3-CONTROL], the term "Attachment Identifier", or
"AI", to refer to a quantity whose purpose is to identify a "AI", to refer to a quantity whose purpose is to identify a
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The Generalized ID FEC element also provides some additional The Generalized ID FEC element also provides some additional
structuring of the identifiers. It is assumed that the SAI and TAI structuring of the identifiers. It is assumed that the SAI and TAI
will sometimes have a common part, called the "Attachment Group will sometimes have a common part, called the "Attachment Group
Identifier" (AGI), such that the SAI and TAI can each be thought of Identifier" (AGI), such that the SAI and TAI can each be thought of
as the concatenation of the AGI with an "Attachment Individual as the concatenation of the AGI with an "Attachment Individual
Identifier" (AII). So the pair of identifiers is encoded into three Identifier" (AII). So the pair of identifiers is encoded into three
fields: AGI, Source AII (SAII), and Target AII (TAII). The SAI is fields: AGI, Source AII (SAII), and Target AII (TAII). The SAI is
the concatenation of the AGI and the SAII, while the TAI is the the concatenation of the AGI and the SAII, while the TAI is the
concatenation of the AGI and the TAII. concatenation of the AGI and the TAII.
Similiarly, [L2TP-L2VPN] allows using one or two Forwarder Similarly, [L2TP-L2VPN] allows using one or two Forwarder Identifiers
Identifiers to set up pseudowires. If only the target Forwarder to set up pseudowires. If only the target Forwarder Identifier is
Identifier is used in L2TP signaling messages, both the source and used in L2TP signaling messages, both the source and target
target Forwarders are assumed to have the same value. If both the Forwarders are assumed to have the same value. If both the source
source and target Forwarder Identifers are carried in L2TP siganling and target Forwarder Identifiers are carried in L2TP signaling
messages, each Forwarder uses a locally significant identifier value. messages, each Forwarder uses a locally significant identifier value.
The Forwarder Identifier in [L2TP-L2VPN] is an equivalent term as The Forwarder Identifier in [L2TP-L2VPN] is an equivalent term as
Attachment Identifer in [PWE3-CONTROL]. A Forwarder Identifier also Attachment Identifier in [PWE3-CONTROL]. A Forwarder Identifier also
consists of an Attachment Group Identifier and an Attachment consists of an Attachment Group Identifier and an Attachment
Individual Identifier. Unlike the Generalized ID FEC element, the Individual Identifier. Unlike the Generalized ID FEC element, the
AGI and AII are carried in distinct L2TP Attribute-Value-Pairs AGI and AII are carried in distinct L2TP Attribute-Value-Pairs
(AVPs). The AGI is encoded in the AGI AVP, and the SAII and TAII are (AVPs). The AGI is encoded in the AGI AVP, and the SAII and TAII are
encoded in the Local End ID AVP and the Remote End ID AVP encoded in the Local End ID AVP and the Remote End ID AVP
respectively. The source Forwarder Identifier is the concatenation respectively. The source Forwarder Identifier is the concatenation
of the AGI and SAII, while the target Forwarder Identifier is the of the AGI and SAII, while the target Forwarder Identifier is the
concatenation of the AGI and TAII. concatenation of the AGI and TAII.
In applications that group sets of PWs into "Layer 2 Virtual Private In applications that group sets of PWs into "Layer 2 Virtual Private
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It should be noted that while different forwarders support different It should be noted that while different forwarders support different
applications, the type of application (e.g., VPLS vs. VPWS) cannot applications, the type of application (e.g., VPLS vs. VPWS) cannot
necessarily be inferred from the forwarders' identifiers. A router necessarily be inferred from the forwarders' identifiers. A router
receiving a signaling message with a particular TAI will have to be receiving a signaling message with a particular TAI will have to be
able to determine which of its local forwarders is identified by that able to determine which of its local forwarders is identified by that
TAI, and to determine the application provided by that forwarder. TAI, and to determine the application provided by that forwarder.
But other nodes may not be able to infer the application simply by But other nodes may not be able to infer the application simply by
inspection of the signaling messages. inspection of the signaling messages.
2.2. Creating a Single Bidirectional Pseudowire 2.2 Creating a Single Bidirectional Pseudowire
In any form of LDP-based signaling, each PW endpoint must initiate In any form of LDP-based signaling, each PW endpoint must initiate
the creation of a unidirectional LSP. A PW is a pair of such LSPs. the creation of a unidirectional LSP. A PW is a pair of such LSPs.
In most of the PPVPN provisioning models, the two endpoints of a In most of the PPVPN provisioning models, the two endpoints of a
given PW can simultaneously initiate the signaling for it. They must given PW can simultaneously initiate the signaling for it. They must
therefore have some way of determining when a given pair of LSPs are therefore have some way of determining when a given pair of LSPs are
intended to be associated together as a single PW. intended to be associated together as a single PW.
The way in which this association is done is different for the The way in which this association is done is different for the
various different L2VPN services and provisioning models. The various different L2VPN services and provisioning models. The
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L2TP signaling inherently establishes a bidirectional session that L2TP signaling inherently establishes a bidirectional session that
carries a PW between two PW endpoints. The two endpoints can also carries a PW between two PW endpoints. The two endpoints can also
simultaneously initiate the signaling for a given PW. It is possible simultaneously initiate the signaling for a given PW. It is possible
that two PWs can be established for a pair of Forwarders. that two PWs can be established for a pair of Forwarders.
In order to avoid setting up duplicated pseudowires between two In order to avoid setting up duplicated pseudowires between two
Forwarders, each PE must be able to independently detect such a Forwarders, each PE must be able to independently detect such a
pseudowire tie. The procedures of detecting a pseudowire tie is pseudowire tie. The procedures of detecting a pseudowire tie is
described in [L2TP-L2VPN] described in [L2TP-L2VPN]
2.3. Attachment Identifiers and Forwarders 2.3 Attachment Identifiers and Forwarders
Every Forwarder in a PE must be associated with an Attachment Every Forwarder in a PE must be associated with an Attachment
Identifier (AI), either through configuration or through some Identifier (AI), either through configuration or through some
algorithm. The Attachment Identifier must be unique in the context algorithm. The Attachment Identifier must be unique in the context
of the PE router in which the Forwarder resides. The combination <PE of the PE router in which the Forwarder resides. The combination <PE
router, AI> must be globally unique. router, AI> must be globally unique.
It is frequently convenient to a set of Forwarders as being members It is frequently convenient to a set of Forwarders as being members
of a particular "group", where PWs may only be set up among members of a particular "group", where PWs may only be set up among members
of a group. In such cases, it is convenient to identify the of a group. In such cases, it is convenient to identify the
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An Attachment Group Identifier may be thought of as a VPN-id, or An Attachment Group Identifier may be thought of as a VPN-id, or
a VLAN identifier, some attribute which is shared by all the a VLAN identifier, some attribute which is shared by all the
Attachment VCs (or pools thereof) which are allowed to be connected. Attachment VCs (or pools thereof) which are allowed to be connected.
The details for how to construct the AGI and AII fields identifying The details for how to construct the AGI and AII fields identifying
the pseudowire endpoints in particular provisioning models are the pseudowire endpoints in particular provisioning models are
discussed later in this paper. discussed later in this paper.
We can now consider an LSP to be identified by: We can now consider an LSP to be identified by:
<PE1, <AGI, AII1>, PE2, <AGI, AII2>>, o <PE1, <AGI, AII1>, PE2, <AGI, AII2>>
and the LSP in the opposite direction will be identified by: and the LSP in the opposite direction will be identified by:
<PE2, <AGI, AII2>, PE1, <AGI, AII1>>; o <PE2, <AGI, AII2>, PE1, <AGI, AII1>>;
a pseudowire is a pair of such LSPs. In the case of using L2TP A pseudowire is a pair of such LSPs. In the case of using L2TP
signaling, these refer to the two directions of an L2TP session. signaling, these refer to the two directions of an L2TP session.
When a signaling message is sent from PE1 to PE2, and PE1 needs to When a signaling message is sent from PE1 to PE2, and PE1 needs to
refer to an Attachment Identifier which has been configured on refer to an Attachment Identifier which has been configured on
one of its own Attachment VCs (or pools), the Attachment one of its own Attachment VCs (or pools), the Attachment
Identifier is called a "Source Attachment Identifier". If PE1 Identifier is called a "Source Attachment Identifier". If PE1
needs to refer to an Attachment Identifier which has been needs to refer to an Attachment Identifier which has been
configured on one of PE2's Attachment VCs (or pools), the configured on one of PE2's Attachment VCs (or pools), the
Attachment Identifier is called a "Target Attachment Identifier". Attachment Identifier is called a "Target Attachment Identifier".
(So an SAI at one endpoint is a TAI at the remote endpoint, and vice (So an SAI at one endpoint is a TAI at the remote endpoint, and vice
versa.) versa.)
In the signaling protocol, we define encodings for the following In the signaling protocol, we define encodings for the following
three fields: three fields:
- Attachment Group Identifier (AGI) o Attachment Group Identifier (AGI)
- Source Attachment Individual Identifier (SAII) o Source Attachment Individual Identifier (SAII)
- Target Attachment Individual Identifier (TAII) o Target Attachment Individual Identifier (TAII)
If the AGI is non-null, then the SAI consists of the AGI together If the AGI is non-null, then the SAI consists of the AGI together
with the SAII, and the TAI consists of the TAII together with the with the SAII, and the TAI consists of the TAII together with the
AGI. If the AGI is null, then the SAII and TAII are the SAI and TAI AGI. If the AGI is null, then the SAII and TAII are the SAI and TAI
respectively. respectively.
The intention is that the PE which receives an LDP Label Mapping The intention is that the PE which receives an LDP Label Mapping
message or an L2TP Incoming Call Request (ICRQ) message containing a message or an L2TP Incoming Call Request (ICRQ) message containing a
TAI will be able to map that TAI uniquely to one of its Attachment TAI will be able to map that TAI uniquely to one of its Attachment
VCs (or pools). The way in which a PE maps a TAI to an Attachment VCs (or pools). The way in which a PE maps a TAI to an Attachment
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3. Applications 3. Applications
In this section, we specify the way in which the pseudowire signaling In this section, we specify the way in which the pseudowire signaling
using the notion of source and target Forwarder is applied for a using the notion of source and target Forwarder is applied for a
number of different applications. For some of the applications, we number of different applications. For some of the applications, we
specify the way in which different provisioning models can be used. specify the way in which different provisioning models can be used.
However, this is not meant to be an exhaustive list of the However, this is not meant to be an exhaustive list of the
applications, or an exhaustive list of the provisioning models that applications, or an exhaustive list of the provisioning models that
can be applied to each application. can be applied to each application.
3.1. Individual Point-to-Point VCs 3.1 Individual Point-to-Point VCs
The signaling specified in this document can be used to set up The signaling specified in this document can be used to set up
individually provisioned point-to-point pseudowires. In this individually provisioned point-to-point pseudowires. In this
application, each Forwarder binds a single PW to a single Attachment application, each Forwarder binds a single PW to a single Attachment
Circuit. Each PE must be provisioned with the necessary set of Circuit. Each PE must be provisioned with the necessary set of
Attachment Circuits, and then certain parameters must be provisioned Attachment Circuits, and then certain parameters must be provisioned
for each Attachment Circuit. for each Attachment Circuit.
3.1.1. Provisioning Models 3.1.1 Provisioning Models
3.1.1.1. Double Sided Provisioning 3.1.1.1 Double Sided Provisioning
In this model, the Attachment Circuit must be provisioned with a In this model, the Attachment Circuit must be provisioned with a
local name, a remote PE address, and a remote name. During local name, a remote PE address, and a remote name. During
signaling, the local name is sent as the SAII, the remote name as the signaling, the local name is sent as the SAII, the remote name as the
TAII, and the AGI is null. If two Attachment Circuits are to be TAII, and the AGI is null. If two Attachment Circuits are to be
connected by a PW, the local name of each must be the remote name of connected by a PW, the local name of each must be the remote name of
the other. the other.
Note that if the local name and the remote name are the same, the Note that if the local name and the remote name are the same, the
PWid FEC element can be used instead of the Generalized ID FEC PWid FEC element can be used instead of the Generalized ID FEC
element in the LDP based signaling. element in the LDP based signaling.
With L2TP signaling, the local name is sent in Local End ID AVP, the With L2TP signaling, the local name is sent in Local End ID AVP, the
remote name in Remote End ID AVP. The AGI AVP is optional. If remote name in Remote End ID AVP. The AGI AVP is optional. If
present, it contains a zero-length AGI value. If the local name and present, it contains a zero-length AGI value. If the local name and
the remote name are the same, Local End ID AVP can be omitted from the remote name are the same, Local End ID AVP can be omitted from
L2TP signaling messages. L2TP signaling messages.
3.1.1.2. Single Sided Provisioning with Discovery 3.1.1.2 Single Sided Provisioning with Discovery
In this model, each Attachment Circuit must be provisioned with a In this model, each Attachment Circuit must be provisioned with a
local name. The local name consists of a VPN-id (signaled as the local name. The local name consists of a VPN-id (signaled as the
AGI) and an Attachment Individual Identifier which is unique relative AGI) and an Attachment Individual Identifier which is unique relative
to the AGI. If two Attachment circuits are to be connected by a PW, to the AGI. If two Attachment circuits are to be connected by a PW,
only one of them needs to be provisioned with a remote name (which of only one of them needs to be provisioned with a remote name (which of
course is the local name of the other Attachment Circuit). Neither course is the local name of the other Attachment Circuit). Neither
needs to be provisioned with the address of the remote PE, but both needs to be provisioned with the address of the remote PE, but both
must have the same VPN-id. must have the same VPN-id.
As part of an auto-discovery procedure, each PE advertises its <VPN- As part of an auto-discovery procedure, each PE advertises its
id, local AII> pairs. Each PE compares its local <VPN-id, remote <VPN-id, local AII> pairs. Each PE compares its local <VPN-id,
AII> pairs with the <VPN-id, local AII> pairs advertised by the other remote AII> pairs with the <VPN-id, local AII> pairs advertised by
PEs. If PE1 has a local <VPN-id, remote AII> pair with value <V, the other PEs. If PE1 has a local <VPN-id, remote AII> pair with
fred>, and PE2 has a local <VPN-id, local AII> pair with value <V, value <V, fred>, and PE2 has a local <VPN-id, local AII> pair with
fred>, PE1 will thus be able to discover that it needs to connect to value <V, fred>, PE1 will thus be able to discover that it needs to
PE2. When signaling, it will use "fred" as the TAII, and will use V connect to PE2. When signaling, it will use "fred" as the TAII, and
as he AGI. PE1's local name for the Attachment Circuit is sent as will use V as he AGI. PE1's local name for the Attachment Circuit is
the SAII. sent as the SAII.
The primary benefit of this provisioning model when compared to The primary benefit of this provisioning model when compared to
Double Sided Provisioning is that it enables one to move an Double Sided Provisioning is that it enables one to move an
Attachment Circuit from one PE to another without having to Attachment Circuit from one PE to another without having to
reconfigure the remote endpoint. reconfigure the remote endpoint.
3.1.2. Signaling 3.1.2 Signaling
The LDP-based signaling is as specified in [PWE3-CONTROL], with the The LDP-based signaling is as specified in [PWE3-CONTROL], with the
addition of the following: addition of the following:
When a PE receives a Label Mapping Message, and the TAI identifies a When a PE receives a Label Mapping Message, and the TAI identifies a
particular Attachment Circuit which is configured to be bound to a particular Attachment Circuit which is configured to be bound to a
point-to-point PW, then the following checks must be made. point-to-point PW, then the following checks must be made.
If the Attachment Circuit is already bound to a pseudowire (including If the Attachment Circuit is already bound to a pseudowire (including
the case where only one of the two LSPs currently exists), and the the case where only one of the two LSPs currently exists), and the
skipping to change at page 11, line 10 skipping to change at page 12, line 17
If the Attachment Circuit is already bound to a pseudowire, but the If the Attachment Circuit is already bound to a pseudowire, but the
pseudowire is bound to a Forwarder on PE1 with the AI different than pseudowire is bound to a Forwarder on PE1 with the AI different than
that specified in the SAI fields of the ICRQ message, then PE2 sends that specified in the SAI fields of the ICRQ message, then PE2 sends
a CDN message to PE1, with a Status Code meaning "Attachment Circuit a CDN message to PE1, with a Status Code meaning "Attachment Circuit
bound to different remote Attachment Circuit", and the processing of bound to different remote Attachment Circuit", and the processing of
the ICRQ message is complete. the ICRQ message is complete.
These errors could occur as the result of misconfigurations. These errors could occur as the result of misconfigurations.
3.2. Virtual Private LAN Service 3.2 Virtual Private LAN Service
In the VPLS application [L2VPN-REQ, VPLS], the Attachment Circuits In the VPLS application [L2VPN-REQ, VPLS], the Attachment Circuits
can be though of as LAN interfaces which attach to "virtual LAN can be though of as LAN interfaces which attach to "virtual LAN
switches", or, in the terminology of [L2VPN-FW], "Virtual Switching switches", or, in the terminology of [L2VPN-FW], "Virtual Switching
Instances" (VSIs). Each Forwarder is a VSI that attaches to a number Instances" (VSIs). Each Forwarder is a VSI that attaches to a number
of PWs and a number of Attachment Circuits. The VPLS service of PWs and a number of Attachment Circuits. The VPLS service
[L2VPN-REQ, VPLS] requires that a single pseudowire be created [L2VPN-REQ, VPLS] requires that a single pseudowire be created
between each pair of VSIs that are in the same VPLS. Each PE device between each pair of VSIs that are in the same VPLS. Each PE device
may have a multiple VSIs, where each VSI belongs to a different VPLS. may have a multiple VSIs, where each VSI belongs to a different VPLS.
3.2.1. Provisioning 3.2.1 Provisioning
Each VPLS must have a globally unique identifier, which we call a Each VPLS must have a globally unique identifier, which we call a
VPN-id. Every VSI must be configured with the VPN-id of the VPLS to VPN-id. Every VSI must be configured with the VPN-id of the VPLS to
which it belongs. which it belongs.
Each VSI must also have a unique identifier, but this can be formed Each VSI must also have a unique identifier, but this can be formed
automatically by concatenating its VPN-id with the IP address of its automatically by concatenating its VPN-id with the IP address of its
PE router. PE router.
3.2.2. Auto-Discovery 3.2.2 Auto-Discovery
3.2.2.1. BGP-based auto-discovery 3.2.2.1 BGP-based auto-discovery
The framework for BGP-based auto-discovery for a VPLS service is as The framework for BGP-based auto-discovery for a VPLS service is as
specified in [BGP-AUTO], section 3.2. specified in [BGP-AUTO], section 3.2.
The AFI/SAFI used would be: The AFI/SAFI used would be:
- An AFI specified by IANA for L2VPN. (This is the same for all o An AFI specified by IANA for L2VPN. (This is the same for all
L2VPN schemes.) L2VPN schemes.)
- An SAFI specified by IANA specifically for an L2VPN (VPLS or o An SAFI specified by IANA specifically for an L2VPN (VPLS or VPWS)
VPWS) service whose pseudowires are set up using the procedures service whose pseudowires are set up using the procedures
described in the current document. described in the current document.
In order to use BGP-based auto-discovery as specified in [BGP-AUTO], In order to use BGP-based auto-discovery as specified in [BGP-AUTO],
the globally unique identifier associated with a VPLS must be the globally unique identifier associated with a VPLS must be
encodable as an 8-byte Route Distinguisher (RD). If the globally encodable as an 8-byte Route Distinguisher (RD). If the globally
unique identifier for a VPLS is an RFC2685 VPN-id, it can be encoded unique identifier for a VPLS is an RFC2685 VPN-id, it can be encoded
as an RD as specified in [BGP-AUTO]. However, any other method of as an RD as specified in [BGP-AUTO]. However, any other method of
assigning a unique identifier to a VPLS and encoding it as an RD assigning a unique identifier to a VPLS and encoding it as an RD
(using the encoding techniques of [RFC2547bis]) will do. (using the encoding techniques of [RFC2547bis]) will do.
Each VSI needs to have a unique identifier, which can be encoded as a Each VSI needs to have a unique identifier, which can be encoded as a
BGP NLRI. This is formed by prepending the RD (from the previous BGP NLRI. This is formed by prepending the RD (from the previous
paragraph) to an IP address of the PE containing the virtual LAN paragraph) to an IP address of the PE containing the virtual LAN
switch. switch. Note that the role of this address is simply a unique
identifier within the VPN; it does not need to be globally routable.
(Note that it is not strictly necessary for all the VSIs in the same (Note also that it is not strictly necessary for all the VSIs in the
VPLS to have the same RD, all that is really necessary is that the same VPLS to have the same RD, all that is really necessary is that
NLRI uniquely identify a virtual LAN switch.) the NLRI uniquely identify a virtual LAN switch.)
Each VSI needs to be associated with one or more Route Target (RT) Each VSI needs to be associated with one or more Route Target (RT)
Extended Communities, as discussed in [BGP-AUTO}. These control the Extended Communities, as discussed in [BGP-AUTO}. These control the
distribution of the NLRI, and hence will control the formation of the distribution of the NLRI, and hence will control the formation of the
overlay topology of pseudowires that constitutes a particular VPLS. overlay topology of pseudowires that constitutes a particular VPLS.
Auto-discovery proceeds by having each PE distribute, via BGP, the Auto-discovery proceeds by having each PE distribute, via BGP, the
NLRI for each of its VSIs, with itself as the BGP next hop, and with NLRI for each of its VSIs, with itself as the BGP next hop, and with
the appropriate RT for each such NLRI. Typically, each PE would be a the appropriate RT for each such NLRI. Typically, each PE would be a
client of a small set of BGP route reflectors, which would client of a small set of BGP route reflectors, which would
skipping to change at page 13, line 5 skipping to change at page 14, line 5
it need not be) an encoding of the VPN-id. If a particular VPLS it need not be) an encoding of the VPN-id. If a particular VPLS
consists of multiple VLANs, each VLAN must have its own unique RT. A consists of multiple VLANs, each VLAN must have its own unique RT. A
VSI can be placed in multiple VLANS (or even in multiple VPLSes) by VSI can be placed in multiple VLANS (or even in multiple VPLSes) by
assigning it multiple RTs. assigning it multiple RTs.
Note that hierarchical VPLS can be set up by assigning multiple RTs Note that hierarchical VPLS can be set up by assigning multiple RTs
to some of the virtual LAN switches; the RT mechanism allows one to to some of the virtual LAN switches; the RT mechanism allows one to
have complete control over the pseudowire overlay which constitutes have complete control over the pseudowire overlay which constitutes
the VPLS topology. the VPLS topology.
3.2.3. Signaling In summary, the BGP advertisement for a particular VSI at a given PE
will contain:
o an NLRI of AFI = L2VPN, SAFI = TBD, encoded as RD:PE_addr
o a BGP next hop equal to the loopback address of the PE
o an extended community attribute containing one or more RTs
3.2.3 Signaling
It is necessary to create Attachment Identifiers which identify the It is necessary to create Attachment Identifiers which identify the
VSIs. Given that each VPLS has at most one VSI per PE, and that only VSIs. In the preceding section, a VSI-ID was encoded as RD:PE_addr
one PW is permitted between any pair of VSIs, a VSI can be uniquely for the purposes of autodiscovery. For signaling purposes, the same
identified (relative to its PE) by the VPN-id of its VPLS. Therefore information is carried but is encoded slightly differently. Noting
the signaling messages can encode the VPN-id in the AGI field, and that the RD is effectively a VPN identifier, we therefore encode the
use the null values of the SAII and TAII fields. RD in the AGI field, and place the PE_addr in the TAII field. The
SAII can be null.
The VPN-id may be encoded as an [RFC2547bis] RD, in which case the The AGI field therefore consists of a length field of value 8,
AGI field consist of a length field of value 8, followed by the 8 followed by the 8 bytes of the RD. The TAII consists of a length
bytes of the RD. If the VPN-id is an RFC2685 VPN-id, it should be field of value 4 followed by the 4-byte PE address.
encoded as an RD (as specified in [BGP-AUTO]), and then the RD should
be carried in the AGI field.
Note that it is not possible using this technique to set up more than Note that it is not possible using this technique to set up more than
one PW per pair of VSIs. one PW per pair of VSIs.
3.2.4. Pseudowires as VPLS Attachment Circuits 3.2.4 Pseudowires as VPLS Attachment Circuits
It is also possible using this technique to set up a PW which It is also possible using this technique to set up a PW which
attaches at one endpoint to a VSI, but at the other endpoint only to attaches at one endpoint to a VSI, but at the other endpoint only to
an Attachment Circuit. However, in this case there may be more than an Attachment Circuit. However, in this case there may be more than
one PW between a pair of PEs, so that AIIs cannot be null. Rather, one PW between a pair of PEs, so that AIIs cannot be null. Rather,
each such PW must have AII which is unique relative to the VPN-id. each such PW must have AII which is unique relative to the VPN-id.
This value would be carried in both the SAII and the TAII field of This value would be carried in both the SAII and the TAII field of
the signaling messages. the signaling messages.
3.3. Colored Pools: Full Mesh of Point-to-Point VCs 3.3 Colored Pools: Full Mesh of Point-to-Point VCs
In the "Colored Pools" model of operation, each PE may contain In the "Colored Pools" model of operation, each PE may contain
several pools of Attachment Circuits, each pool associated with a several pools of Attachment Circuits, each pool associated with a
particular VPN. A PE may contain multiple pools per VPN, as each particular VPN. A PE may contain multiple pools per VPN, as each
pool may correspond to a particular CE device. It may be desired to pool may correspond to a particular CE device. It may be desired to
create one pseudowire between each pair of pools that are in the same create one pseudowire between each pair of pools that are in the same
VPN; the result would be to create a full mesh of CE-CE VCs for each VPN; the result would be to create a full mesh of CE-CE VCs for each
VPN. VPN.
3.3.1. Provisioning 3.3.1 Provisioning
Each pool is configured, and associated with: Each pool is configured, and associated with:
- a set of Attachment Circuits; whether these Attachment Circuits o a set of Attachment Circuits; whether these Attachment Circuits
must themselves be provisioned, or whether they can be auto- must themselves be provisioned, or whether they can be
allocated as needed, is independent of and orthogonal to the auto-allocated as needed, is independent of and orthogonal to the
procedures described in this document; procedures described in this document;
- a "color", which can be thought of as a VPN-id of some sort; o a "color", which can be thought of as a VPN-id of some sort;
- a relative pool identifier, which is unique relative to the o a relative pool identifier, which is unique relative to the color.
color.
The pool identifier, and color, taken together, constitute a globally The pool identifier, and color, taken together, constitute a globally
unique identifier for the pool. Thus if there are n pools of a given unique identifier for the pool. Thus if there are n pools of a given
color, their pool identifiers can be (though they do not need to be) color, their pool identifiers can be (though they do not need to be)
the numbers 1-n. the numbers 1-n.
The semantics are that a pseudowire will be created between every The semantics are that a pseudowire will be created between every
pair of pools that have the same color, where each such pseudowire pair of pools that have the same color, where each such pseudowire
will be bound to one Attachment Circuit from each of the two pools. will be bound to one Attachment Circuit from each of the two pools.
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the way the colors are assigned to the pools. To create a full mesh, the way the colors are assigned to the pools. To create a full mesh,
the "color" would just be a VPN-id. the "color" would just be a VPN-id.
Optionally, a particular Attachment Circuit may be configured with Optionally, a particular Attachment Circuit may be configured with
the relative pool identifier of a remote pool. Then that Attachment the relative pool identifier of a remote pool. Then that Attachment
Circuit would be bound to a particular pseudowire only if that Circuit would be bound to a particular pseudowire only if that
pseudowire's remote endpoint is the pool with that relative pool pseudowire's remote endpoint is the pool with that relative pool
identifier. With this option, the same pairs of Attachment Circuits identifier. With this option, the same pairs of Attachment Circuits
will always be bound via pseudowires. will always be bound via pseudowires.
3.3.2. Auto-Discovery 3.3.2 Auto-Discovery
3.3.2.1. BGP-based auto-discovery 3.3.2.1 BGP-based auto-discovery
The framework for BGP-based auto-discovery for a colored pool service The framework for BGP-based auto-discovery for a colored pool service
is as specified in [BGP-AUTO], section 3.2. is as specified in [BGP-AUTO], section 3.2.
The AFI/SAFI used would be: The AFI/SAFI used would be:
- An AFI specified by IANA for L2VPN. (This is the same for all o An AFI specified by IANA for L2VPN. (This is the same for all
L2VPN schemes.) L2VPN schemes.)
- An SAFI specified by IANA specifically for an L2VPN (VPLS or
VPWS) service whose pseudowires are set up using the procedures o An SAFI specified by IANA specifically for an L2VPN (VPLS or VPWS)
service whose pseudowires are set up using the procedures
described in the current document. described in the current document.
In order to use BGP-based auto-discovery, the color associated with a In order to use BGP-based auto-discovery, the color associated with a
colored pool must be encodable as both an RT (Route Target) and an RD colored pool must be encodable as both an RT (Route Target) and an RD
(Route Distinguisher). The globally unique identifier of a pool must (Route Distinguisher). The globally unique identifier of a pool must
be encodable as NLRI; the color would be encoded as the RD and the be encodable as NLRI; the color would be encoded as the RD and the
pool identifier as a four-byte quantity which is appended to the RD pool identifier as a four-byte quantity which is appended to the RD
to create the NLRI. to create the NLRI.
Auto-discovery procedures by having each PE distribute, via BGP, the Auto-discovery procedures by having each PE distribute, via BGP, the
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If a PE has a pool with a particular color, it can then receive all If a PE has a pool with a particular color, it can then receive all
the NLRI which have that same color, and from the BGP next hop the NLRI which have that same color, and from the BGP next hop
attribute of these NLRI will learn the IP addresses of the other PE attribute of these NLRI will learn the IP addresses of the other PE
routers which have pools switches with the same color. It also routers which have pools switches with the same color. It also
learns the unique identifier of each such remote pool, as this is learns the unique identifier of each such remote pool, as this is
encoded in the NLRI. The remote pool's relative identifier can be encoded in the NLRI. The remote pool's relative identifier can be
extracted from the NLRI and used in the signaling, as specified extracted from the NLRI and used in the signaling, as specified
below. below.
3.3.3. Signaling In summary, the BGP advertisement for a particular pool of attachment
circuits at a given PE will contain:
o an NLRI of AFI = L2VPN, SAFI = TBD, encoded as RD:pool_num;
o a BGP next hop equal to the loopback address of the PE;
o an extended community attribute containing one or more RTs.
3.3.3 Signaling
When a PE sends a Label Mapping message or an ICRQ message to set up When a PE sends a Label Mapping message or an ICRQ message to set up
a PW between two pools, it encodes the color as the AGI, the local a PW between two pools, it encodes the color as the AGI, the local
pool's relative identifier as the SAII, and the remote pool's pool's relative identifier as the SAII, and the remote pool's
relative identifier as the TAII. relative identifier as the TAII.
When PE2 receives a Label Mapping message or an ICRQ message from When PE2 receives a Label Mapping message or an ICRQ message from
PE1, and the TAI identifies to a pool, and there is already an PE1, and the TAI identifies to a pool, and there is already an
pseudowire connecting an Attachment Circuit in that pool to an pseudowire connecting an Attachment Circuit in that pool to an
Attachment Circuit at PE1, and the AI at PE1 of that pseudowire is Attachment Circuit at PE1, and the AI at PE1 of that pseudowire is
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meaning "Attachment Circuit already bound to remote Attachment meaning "Attachment Circuit already bound to remote Attachment
Circuit". This prevents the creation of multiple pseudowires between Circuit". This prevents the creation of multiple pseudowires between
a given pair of pools. a given pair of pools.
Note that the signaling itself only identifies the remote pool to Note that the signaling itself only identifies the remote pool to
which the pseudowire is to lead, not the remote Attachment Circuit which the pseudowire is to lead, not the remote Attachment Circuit
which is to be bound to the the pseudowire. However, the remote PE which is to be bound to the the pseudowire. However, the remote PE
may examine the SAII field to determine which Attachment Circuit may examine the SAII field to determine which Attachment Circuit
should be bound to the pseudowire. should be bound to the pseudowire.
3.4. Colored Pools: Partial Mesh 3.4 Colored Pools: Partial Mesh
The procedures for creating a partial mesh of pseudowires among a set The procedures for creating a partial mesh of pseudowires among a set
of colored pools are substantially the same as those for creating a of colored pools are substantially the same as those for creating a
full mesh, with the following exceptions: full mesh, with the following exceptions:
- Each pool is optionally configured with a set of "import RTs" and o Each pool is optionally configured with a set of "import RTs" and
"export RTs"; "export RTs";
- During BGP-based auto-discovery, the pool color is still encoded o During BGP-based auto-discovery, the pool color is still encoded
in the RD, but if the pool is configured with a set of "export in the RD, but if the pool is configured with a set of "export
RTs", these are are encoded in the RTs of the BGP Update RTs", these are are encoded in the RTs of the BGP Update messages,
messages, INSTEAD the color. INSTEAD the color;
- If a pool has a particular "import RT" value X, it will create a o If a pool has a particular "import RT" value X, it will create a
PW to every other pool which has X as one of its "export RTs". PW to every other pool which has X as one of its "export RTs".
The signaling messages and procedures themselves are as in The signaling messages and procedures themselves are as in section
section 3.3.3. 3.3.3.
3.5. Distributed VPLS 3.5 Distributed VPLS
In Distributed VPLS ([L2VPN-FW], [DTLS], [LPE]), the VPLS In Distributed VPLS ([L2VPN-FW], [DTLS], [LPE]), the VPLS
functionality of a PE router is divided among two systems: a U-PE and functionality of a PE router is divided among two systems: a U-PE and
an N-PE. The U-PE sits between the user and the N-PE. VSI an N-PE. The U-PE sits between the user and the N-PE. VSI
functionality (e.g., MAC address learning and bridging) is performed functionality (e.g., MAC address learning and bridging) is performed
on the U-PE. A number of U-PEs attach to an N-PE. For each VPLS on the U-PE. A number of U-PEs attach to an N-PE. For each VPLS
supported by a U-PE, the U-PE maintains a pseudowire to each other supported by a U-PE, the U-PE maintains a pseudowire to each other
U-PE in the same VPLS. However, the U-PEs do not maintain signaling U-PE in the same VPLS. However, the U-PEs do not maintain signaling
control connections with each other. Rather, each U-PE has only a control connections with each other. Rather, each U-PE has only a
single signaling connection, to its N-PE. In essence, each U-PE-to- single signaling connection, to its N-PE. In essence, each
U-PE pseudowire is composed of three pseudowires spliced together: U-PE-to-U-PE pseudowire is composed of three pseudowires spliced
one from U-PE to N-PE, one from N-PE to N-PE, and one from N-PE to together: one from U-PE to N-PE, one from N-PE to N-PE, and one from
U-PE. N-PE to U-PE.
Consider for example the following topology: Consider for example the following topology:
U-PE A-----| |----U-PE C U-PE A-----| |----U-PE C
| | | |
| | | |
N-PE E--------N-PE F N-PE E--------N-PE F
| | | |
| | | |
U-PE B-----| |-----U-PE D U-PE B-----| |-----U-PE D
where the four U-PEs are in a common VPLS. We now illustrate how PWs where the four U-PEs are in a common VPLS. We now illustrate how PWs
get spliced together in the above topology in order to establish the get spliced together in the above topology in order to establish the
necessary PWs from U-PE A to the other U-PEs. necessary PWs from U-PE A to the other U-PEs.
There are three PWs from A to E. Call these A-E/1, A-E/2, and A-E/3. There are three PWs from A to E. Call these A-E/1, A-E/2, and A-E/3.
In order to connect A properly to the other U-PEs, there must be two In order to connect A properly to the other U-PEs, there must be two
PWs from E to F (call these E-F/1 and E-F/2), one PW from E to B (E- PWs from E to F (call these E-F/1 and E-F/2), one PW from E to B
B/1), one from F to C (F-C/1), and one from F to D (F-D/1). (E-B/1), one from F to C (F-C/1), and one from F to D (F-D/1).
The N-PEs must then splice these pseudowires together to get the The N-PEs must then splice these pseudowires together to get the
equivalent of what the non-distributed VPLS signaling mechanism would equivalent of what the non-distributed VPLS signaling mechanism would
provide: provide:
- PW from A to B: A-E/1 gets spliced to E-B/1. o PW from A to B: A-E/1 gets spliced to E-B/1.
- PW from A to C: A-E/2 gets spliced to E-F/1 gets spliced to F- o PW from A to C: A-E/2 gets spliced to E-F/1 gets spliced to F-C/1.
C/1.
- PW from A to D: A-E/3 gets spliced to E-F/2 gets spliced to F- o PW from A to D: A-E/3 gets spliced to E-F/2 gets spliced to F-D/1.
D/1.
It doesn't matter which PWs get spliced together, as long as the It doesn't matter which PWs get spliced together, as long as the
result is one from A to each of B, C, and D. result is one from A to each of B, C, and D.
Similarly, there are additional PWs which must get spliced together Similarly, there are additional PWs which must get spliced together
to properly interconnect U-PE B with U-PEs C and D, and to to properly interconnect U-PE B with U-PEs C and D, and to
interconnect U-PE C with U-PE D. interconnect U-PE C with U-PE D.
One can see that distributed VPLS does not reduce the number of One can see that distributed VPLS does not reduce the number of
pseudowires per U-PE, but it does reduce the number of control pseudowires per U-PE, but it does reduce the number of control
connections per U-PE. Whether this is worthwhile depends, of course, connections per U-PE. Whether this is worthwhile depends, of course,
on what the bottleneck is. on what the bottleneck is.
3.5.1. Signaling 3.5.1 Signaling
The signaling to support Distributed VPLS can be done with the The signaling to support Distributed VPLS can be done with the
mechanisms described in this paper. However, the procedures for VPLS mechanisms described in this paper. However, the procedures for VPLS
(section 3.2.3) presuppose that, between a pair of PEs, there is only (section 3.2.3) need some additional machinery to ensure that the
one PW per VPLS. In distributed VPLS, this isn't so. In the appropriate number of PWs are established between the various N-PEs
topology above, for example, there are two PWs between A and E for and U-PEs, and among the N-PEs.
the same VPLS. For distributed VPLS therefore, one cannot identify
the Forwarders merely by using the VPN-id as the AGI, while using
null values of the SAII and TAII. Rather, the SAII and TAII must be
used to identify particular U-PE devices.
At a given N-PE, the directly attached U-PEs in a given VPLS can be At a given N-PE, the directly attached U-PEs in a given VPLS can be
numbered from 1 to n. This number identifies the U-PE relative to a numbered from 1 to n. This number identifies the U-PE relative to a
particular VPN-id and a particular PE. (That is, to uniquely particular VPN-id and a particular N-PE. (That is, to uniquely
identify the U-PE, the N-PE, the VPN-id, and the U-PE number must be identify the U-PE, the N-PE, the VPN-id, and the U-PE number must be
known.) known.)
As a result of configuration/discovery, each U-PE must be given a As a result of configuration/discovery, each U-PE must be given a
list of <j, IP address> pairs. Each element in this list tells the list of <j, IP address> pairs. Each element in this list tells the
U-PE to set up j PWs to the specified IP address. When the U-PE U-PE to set up j PWs to the specified IP address. When the U-PE
signals to the N-PE, it sets the AGI to the proper-VPN-id, and sets signals to the N-PE, it sets the AGI to the proper-VPN-id, and sets
the SAII to the PW number, and sets the TAII to null. the SAII to the PW number, and sets the TAII to null.
In the above example, U-PE A would be told <3, E>, telling it to set In the above example, U-PE A would be told <3, E>, telling it to set
up 3 PWs to E. When signaling, A would set the AGI to the proper up 3 PWs to E. When signaling, A would set the AGI to the proper
VPN-id, and would set the SAII to 1, 2, or 3, depending on which of VPN-id, and would set the SAII to 1, 2, or 3, depending on which of
the three PWs it is signaling. the three PWs it is signaling.
As a result of configuration/discovery, each N-PE must be given the As a result of configuration/discovery, each N-PE must be given the
following information for each VPLS: following information for each VPLS:
- A "Local" list: {<j, IP address>}, where each element tells it to o A "Local" list: {<j, IP address>}, where each element tells it to
set up j PWs to the locally attached U-PE at the specified set up j PWs to the locally attached U-PE at the specified
address. The number of elements in this list will be n, the address. The number of elements in this list will be n, the
number of locally attached U-PEs in this VPLS. In the above number of locally attached U-PEs in this VPLS. In the above
example, E would be given the local list: {<3, A>, <3, B>}, example, E would be given the local list: {<3, A>, <3, B>},
telling it to set up 3 PWs to A and 3 to B. telling it to set up 3 PWs to A and 3 to B.
- A local numbering, relative to the particular VPLS and the o A local numbering, relative to the particular VPLS and the
particular N-PE, of its U-PEs. In the above example, E could be particular N-PE, of its U-PEs. In the above example, E could be
told that U-PE A is 1, and U-PE B is 2. told that U-PE A is 1, and U-PE B is 2.
- A "Remote" list: {<IP address, k>}, telling it to set up k PWs, o A "Remote" list: {<IP address, k>}, telling it to set up k PWs,
for each U-PE, to the specified IP address. Each of these IP for each U-PE, to the specified IP address. Each of these IP
addresses identifies a N-PE, and k specifies the number of U-PEs addresses identifies a N-PE, and k specifies the number of U-PEs
at that N-PE which are in the VPLS. In the above example, E at that N-PE which are in the VPLS. In the above example, E would
would be given the remote list: {<2, F>}. Since N-PE E has two be given the remote list: {<2, F>}. Since N-PE E has two U-PEs,
U-PEs, this tells it to set up 4 PWs to N-PE F, 2 for each of its this tells it to set up 4 PWs to N-PE F, 2 for each of its E's
E's U-PEs. U-PEs.
The signaling of a PW from N-PE to U-PE is based on the local list The signaling of a PW from N-PE to U-PE is based on the local list
and the local numbering of U-PEs. When signaling a particular PW and the local numbering of U-PEs. When signaling a particular PW
from an N-PE to a U-PE, the AGI is set to the proper VPN-id, and SAII from an N-PE to a U-PE, the AGI is set to the proper VPN-id, and SAII
is set to null, and the TAII is set to the PW number (relative to is set to null, and the TAII is set to the PW number (relative to
that particular VPLS and U-PE). In the above example, when E signals that particular VPLS and U-PE). In the above example, when E signals
to A, it would set the TAII to be 1, 2, or 3, respectively, for the to A, it would set the TAII to be 1, 2, or 3, respectively, for the
three PWs it must set up to A. It would similarly signal three PWs three PWs it must set up to A. It would similarly signal three PWs
to B. to B.
The LSP signaled from U-PE to N-PE is associated with an LSP from N- The LSP signaled from U-PE to N-PE is associated with an LSP from
PE to U-PE in the usual manner. A PW between a U-PE and an N-PE is N-PE to U-PE in the usual manner. A PW between a U-PE and an N-PE is
known as a "U-PW". known as a "U-PW".
The signaling of a PW from N-PE to N-PE is based on the remote list. The signaling of the appropriate set of PWs from N-PE to N-PE is
based on the remote list. The PWs between the N-PEs can all be
considered equivalent. As long as the correct total number of PWs
are established, the N-PEs can splice these PWs to appropriate U-PWs.
The signaling of the correct number of PWs from N-PE to N-PE is based
on the remote list. The remote list specifies the number of PWs to
set up, per local U-PE, to a particular remote N-PE.
When signaling a particular PW from an N-PE to an N-PE, the AGI is When signaling a particular PW from an N-PE to an N-PE, the AGI is
set to the appropriate VPN-id. The remote list specifies the number set to the appropriate VPN-id. The TAII identifies the remote N-PE,
of PWs to set up, per local U-PE, to a particular remote N-PE. If as in the non-distributed case, i.e. it contains an IP address of
there are n such PWs, they are distinguished by the setting of the the remote N-PE. If there are n such PWs, they are distinguished by
TAII, which will be a number from 1 to n inclusive. The SAII is set the setting of the SAII, which will be a number from 1 to n
to the local number of the U-PE. In the above example, E would set inclusive. A PW between two N-PEs is known as an "N-PW".
up 4 PWs to F. The SAII/TAII fields would be set to 1/1, 1/2, 2/1,
and 2/2 respectively. A PW between two N-PEs is known as an "N-PW".
Each U-PW must be "spliced" to an N-PW. This is based on the remote Each U-PW must be "spliced" to an N-PW. This is based on the remote
list. If the remote list contains an element <i, F>, then i U-PWs list. If the remote list contains an element <i, F>, then i U-PWs
from each local U-PE must be spliced to i N-PWs from the remote N-PE from each local U-PE must be spliced to i N-PWs from the remote N-PE
F. It does not matter which U-PWs are spliced to which N-PWs, as F. It does not matter which U-PWs are spliced to which N-PWs, as
long as this constraint is met. long as this constraint is met.
If an N-PE has more than one local U-PE for a given VPLS, it must If an N-PE has more than one local U-PE for a given VPLS, it must
also ensure that a U-PW from each such U-PE is spliced to a U-PW also ensure that a U-PW from each such U-PE is spliced to a U-PW
from each of the other U-PEs. from each of the other U-PEs.
3.5.2. Provisioning and Discovery 3.5.2 Provisioning and Discovery
Every N-PE must be provisioned with the set of VPLS instances it Every N-PE must be provisioned with the set of VPLS instances it
supports, a VPN-id for each one, and a list of local U-PEs for each supports, a VPN-id for each one, and a list of local U-PEs for each
such VPLS. As part of the discovery procedure, the N-PE advertises such VPLS. As part of the discovery procedure, the N-PE advertises
the number of U-PEs for each VPLS. the number of U-PEs for each VPLS.
Auto-discovery (e.g., BGP-based) can be used to discover all the Auto-discovery (e.g., BGP-based) can be used to discover all the
other N-PEs in the VPLS, and for each, the number of U-PEs local to other N-PEs in the VPLS, and for each, the number of U-PEs local to
that N-PE. From this, one can compute the total number of U-PEs in that N-PE. From this, one can compute the total number of U-PEs in
the VPLS. This information is sufficient to enable one to compute the VPLS. This information is sufficient to enable one to compute
the local list and the remote list for each N-PE. the local list and the remote list for each N-PE.
3.5.3. Non-distributed VPLS as a sub-case 3.5.3 Non-distributed VPLS as a sub-case
A PE which is providing "non-distributed VPLS" (i.e., a PE which A PE which is providing "non-distributed VPLS" (i.e., a PE which
performs both the U-PE and N-PE functions) can interoperate with N- performs both the U-PE and N-PE functions) can interoperate with
PE/U-PE pairs that are providing distributed VPLS. The "non- N-PE/U-PE pairs that are providing distributed VPLS. The
distributed PE" simply advertises, in the discovery procedure, that "non-distributed PE" simply advertises, in the discovery procedure,
it has one local U-PE per VPLS. And of course, the non-distributed that it has one local U-PE per VPLS. And of course, the
PE does no splicing. non-distributed PE does no splicing.
If every PE in a VPLS is providing non-distributed VPLS, and thus If every PE in a VPLS is providing non-distributed VPLS, and thus
every PE advertises itself as an N-PE with one local U-PE, the every PE advertises itself as an N-PE with one local U-PE, the
resultant signaling is exactly the same as that specified in section resultant signaling is exactly the same as that specified in section
3.2.3 above, except that SAII and TAII values of 1 are used instead 3.2.3 above, except that an SAII value of 1 is used instead of null.
of SAII and TAII values of null. (A PE providing non-distributed (A PE providing non-distributed VPLS should therefore treat SAII
VPLS should therefore treat AII values of 1 the same as it treats AII values of 1 the same as it treats SAII values of null.)
values of null.)
3.5.4. Inter-Provider Application of Dist. VPLS Signaling 3.5.4 Splicing and the Data Plane
Consider the following topology: Splicing two PWs together is quite straightforward in the MPLS data
plane, as moving a packet from one PW directly to another is just a
label replace operation on the PW label. When a PW consists of two
PWs spliced together, it is assumed that the data will go to the node
where the splicing is being done, i.e., that the data path will
include the control points.
In some cases, it may be desired to have the data go on a more direct
route from one "true endpoint" to another, without necessarily
passing through the splice points. This could be done by means of a
new LDP TLV carried in the LDP mapping message; call it the "direct
route" TLV. A direct route TLV would be placed in an LDP Label
Mapping message by the LSP's "true endpoint". The TLV would specify
the IP address of the true endpoint, and would also specify a label,
representing the pseudowire, which is assigned by that endpoint.
When PWs are spliced together at intermediate control points, this
TLV would simply be passed upstream. Then when a frame is first put
on the pseudowire, it can be given this pseudowire label, and routed
to the true endpoint, thereby possibly bypassing the intermediate
control points.
Further details on splicing are discussed in [PW-SWITCH].
4. Inter-AS Operation
The provisioning, autodiscovery and signaling mechanisms described
above can all be applied in an inter-AS environment. As in [2547bis]
there are a number of options for inter-AS operation.
4.1 Multihop EBGP redistribution of L2VPN NLRIs
This option is most like option (c) in [2547bis]. That is, we use
multihop EBGP redistribution of L2VPN NLRIs between source and
destination ASes, with EBGP redistribution of labeled IPv4 routes
from AS to neighboring AS.
An ASBR must maintain labeled IPv4 /32 routes to the PE routers
within its AS. It uses EBGP to distribute these routes to other
ASes. ASBRs in any transit ASes will also have to use EBGP to pass
along the labeled /32 routes. This results in the creation of a
label switched path from the ingress PE router to the egress PE
router. Now PE routers in different ASes can establish multi-hop
EBGP connections to each other, and can exchange L2VPN NLRIs over
those connections. Following such exchanges a pair of PEs in
different ASs could establish an LDP session to signal PWs between
each other.
For VPLS, the BGP advertisement and PW signaling are exactly as
described in Section 3.2. As a result of the multihop EBGP session
that exists between source and destination AS, the PEs in one AS that
have VSIs of a certain VPLS will discover the PEs in another AS that
have VSIs of the same VPLS. These PEs will then be able to establish
the appropriate PW signaling protocol session and establish the full
mesh of VSI-VSI pseudowires to build the VPLS as described in Section
3.2.3.
For VPWS, the BGP advertisement and PW signaling are exactly as
described in Section 3.3. As a result of the multihop EBGP session
that exists between source and destination AS, the PEs in one AS that
have pools of a certain color (VPN) will discover PEs in another AS
that have pools of the same color. These PEs will then be able to
establish the appropriate PW signaling protocol session and establish
the full mesh of pseudowires as described in Section 3.2.3. A
partial mesh can similarly be established using the procedures of
Section 3.4.
4.2 EBGP redistribution of L2VPN NLRIs with Pseudowire Switching
A possible drawback of the approach of the previous section is that
it creates PW signaling sessions among all the PEs of a given L2VPN
(VPLS or VPWS). This means a potentially large number of LDP or
L2TPv3 sessions will cross the AS boundary and that these session
connect to many devices within an AS. In the case were the ASes
belong to different providers, one might imagine that providers would
like to have fewer signaling sessions crossing the AS boundary and
that the entities that terminate the sessions could be restricted to
a smaller set of devices. These concerns motivate the approach
described here.
[PW-SWITCH] describes an approach to "switching" packets from one
pseudowire to another at a particular node. This approach allows an
end-to-end pseudowire to be constructed out of several pseudowire
segments, without maintaining an end-to-end control connection. We
can use this approach to produce an inter-AS solution that more
closely resembles option (b) in [2547bis].
In this model, we use EBGP redistribution of L2VPN NLRI from AS to
neighboring AS. First, the PE routers use IBGP to redistribute L2VPN
NLRI either to an Autonomous System Border Router (ASBR), or to a
route reflector of which an ASBR is a client. The ASBR then uses
EBGP to redistribute those L2VPN NLRI to an ASBR in another AS, which
in turn distributes them to the PE routers in that AS, or perhaps to
another ASBR which in turn distributes them, and so on.
In this case, a PE can learn the address of an ASBR through which it
could reach another PE to which it wishes to establish a PW. That
is, a local PE will receive a BGP advertisement containing L2VPN NLRI
corresponding to an L2VPN instance in which the local PE has some
attached members. The BGP next-hop for that L2VPN NLRI will be an
ASBR of the local AS. Then, rather than building a control
connection all the way to the remote PE, it builds one only to the
ASBR. A pseudowire segment can now be established from the PE to the
ASBR. The ASBR in turn can establish a PW to the ASBR of the next
AS, and use "PW switching" to splice that PW to the PW from the PE.
Repeating the process at each ASBR leads to a sequence of PW segments
that, when spliced together, connect the two PEs.
When this approach is used for VPLS, or for full-mesh VPWS, it leads
to a full mesh of pseudowires among the PEs, just as in the previous
section, but it does not produce a full mesh of control connections
(LDP or L2TPv3 sessions). Instead the control connections within a
single AS run among all the PEs of that AS and the ASBRs of the AS.
A single control connection between the ASBRs of adjacent ASes can be
used to support however many AS-to-AS pseudowire segments are needed.
4.3 Inter-Provider Application of Dist. VPLS Signaling
An alternative approach to inter-provider VPLS can be derived from
the Distributed VPLS approach described above. Consider the
following topology:
PE A ---- Network 1 ----- Border ----- Border ----- Network 2 ---- PE B PE A ---- Network 1 ----- Border ----- Border ----- Network 2 ---- PE B
Router 12 Router 21 | Router 12 Router 21 |
| |
PE C PE C
where A, B, and C are PEs in a common VPLS, but Networks 1 and 2 are where A, B, and C are PEs in a common VPLS, but Networks 1 and 2 are
networks of different Service Providers. Border Router 12 is networks of different Service Providers. Border Router 12 is
Network 1's border router to network 2, and Border Router 21 is Network 1's border router to network 2, and Border Router 21 is
Network 2's border router to Network 1. We suppose further that the Network 2's border router to Network 1. We suppose further that the
skipping to change at page 21, line 11 skipping to change at page 24, line 32
not want each of its PEs to have a control connection to any PEs in not want each of its PEs to have a control connection to any PEs in
the other network. Rather, it wants the inter-provider control the other network. Rather, it wants the inter-provider control
connections to run only between the two border routers. connections to run only between the two border routers.
This can be achieved using the techniques of section 3.5, where the This can be achieved using the techniques of section 3.5, where the
PEs behave like U-PEs, and the BRs behave like N-PEs. In the example PEs behave like U-PEs, and the BRs behave like N-PEs. In the example
topology, PE A would behave like a U-PE which is locally attached to topology, PE A would behave like a U-PE which is locally attached to
BR12; PEs B and C would be have like U-PEs which are locally attached BR12; PEs B and C would be have like U-PEs which are locally attached
to BR21; and the two BRs would behave like N-PEs. to BR21; and the two BRs would behave like N-PEs.
As a result, the PW from A to B would consist of three segments: A- As a result, the PW from A to B would consist of three segments:
BR12, BR12-BR21, and BR21-B. The border routers would have to splice A-BR12, BR12-BR21, and BR21-B. The border routers would have to
the corresponding segments together. splice the corresponding segments together.
This requires the PEs within a VPLS to be numbered from 1-n (relative This requires the PEs within a VPLS to be numbered from 1-n (relative
to that VPLS) within a given network. to that VPLS) within a given network.
3.5.5. Splicing and the Data Plane 5. Security Considerations
Splicing two PWs together is quite straightforward in the MPLS data
plane, as moving a packet from one PW directly to another is just a
label replace operation on the PW label. When a PW consists of two
PWs spliced together, it is assumed that the data will go to the node
where the splicing is being done, i.e., that the data path will
include the control points.
In some cases, it may be desired to have the data go on a more direct
route from one "true endpoint" to another, without necessarily
passing through the splice points. This could be done by means of a
new LDP TLV carried in the LDP mapping message; call it the "direct
route" TLV. A direct route TLV would be placed in an LDP Label
Mapping message by the LSP's "true endpoint". The TLV would specify
the IP address of the true endpoint, and would also specify a label,
representing the pseudowire, which is assigned by that endpoint.
When PWs are spliced together at intermediate control points, this
TLV would simply be passed upstream. Then when a frame is first put
on the pseudowire, it can be given this pseudowire label, and routed
to the true endpoint, thereby possibly bypassing the intermediate
control points.
4. Security Considerations
This document describes a number of different L2VPN provisioning This document describes a number of different L2VPN provisioning
models, and specifies the endpoint identifiers that are required to models, and specifies the endpoint identifiers that are required to
support each of the provisioning models. It also specifies how those support each of the provisioning models. It also specifies how those
endpoint identifiers are mapped into fields of auto-discovery endpoint identifiers are mapped into fields of auto-discovery
protocols and signaling protocols. protocols and signaling protocols.
The security considerations related to the signaling and auto- The security considerations related to the signaling and
discovery protocols are discussed in the relevant protocol auto-discovery protocols are discussed in the relevant protocol
specifications ([BGP-AUTO], [L2TP-BASE], [L2TP-L2VPN], [LDP], [PWE3- specifications ([BGP-AUTO], [L2TP-BASE], [L2TP-L2VPN], [LDP],
CONTROL]). [PWE3-CONTROL]).
The security considerations related to the particular kind of L2VPN The security considerations related to the particular kind of L2VPN
service being supported are discussed in [L2VPN-REQS], [L2VPN-FW], service being supported are discussed in [L2VPN-REQS], [L2VPN-FW],
and [VPLS]. and [VPLS].
The security consideration of inter-AS operation are similar to those
for inter-AS L3VPNs [2547bis].
The way in which endpoint identifiers are mapped into protocol fields The way in which endpoint identifiers are mapped into protocol fields
does not create any additional security issues. does not create any additional security issues.
5. Acknowledgments 6. Acknowledgments
Thanks to Dan Tappan, Ted Qian, Bruce Davie, Ali Sajassi, Skip Booth, Thanks to Dan Tappan, Ted Qian, Ali Sajassi, Skip Booth, Luca Martini
and Francois LeFaucheur for their comments, criticisms, and helpful and Francois LeFaucheur for their comments, criticisms, and helpful
suggestions. suggestions.
Thanks to Tissa Senevirathne, Hamid Ould-Brahim and Yakov Rekhter for Thanks to Tissa Senevirathne, Hamid Ould-Brahim and Yakov Rekhter for
discussing the auto-discovery issues. discussing the auto-discovery issues.
Thanks to Vach Kompella for a continuing discussion of the proper Thanks to Vach Kompella for a continuing discussion of the proper
semantics of the generalized identifiers. semantics of the generalized identifiers.
6. References 7. References
[BGP-AUTO] "Using BGP as an Auto-Discovery Mechanism for Network- [BGP-AUTO] "Using BGP as an Auto-Discovery Mechanism for
based VPNs", Ould-Brahim et. al., draft-ietf-l3vpn-bgpvpn-auto- Network-based VPNs", Ould-Brahim et. al.,
04.txt, May 2004 draft-ietf-l3vpn-bgpvpn-auto-05.txt, February 2005
[L2TP-BASE] "Layer Two Tunneling Protocol (Version 3)", Lau et. al., [L2TP-BASE] "Layer Two Tunneling Protocol (Version 3)", Lau et. al.,
draft-ietf-l2tpext-l2tp-base-14.txt, June 2004 draft-ietf-l2tpext-l2tp-base-14.txt, June 2004
[L2TP-L2VPN] "L2VPN Extensions for L2TP", Luo, draft-ietf-l2tpext- [L2TP-L2VPN] "L2VPN Extensions for L2TP", Luo,
l2vpn-01.txt, Jul 2004 draft-ietf-l2tpext-l2vpn-01.txt, Jul 2004
[L2VPN-FW] "L2VPN Framework", Andersson et. al.,
draft-ietf-l2vpn-l2-framework-05.txt, June 2004
[L2VPN-FW] "L2VPN Framework", Andersson et. al., draft-ietf-l2vpn-
l2-framework-05.txt, June 2004
[L2VPN-REQ] "Service Requirements for Layer 2 Provider Provisioned [L2VPN-REQ] "Service Requirements for Layer 2 Provider Provisioned
Virtual Private Network Services", Augustyn, Serbest, et. al., Virtual Private Network Services", Augustyn, Serbest, et. al.,
draft-ietf-l2vpn-requirements-02.txt, September 2004 draft-ietf-l2vpn-requirements-02.txt, September 2004
[L2VPN-TERM] "PPVPN Terminology", Andersson, Madsen, draft-ietf- [L2VPN-TERM] "PPVPN Terminology", Andersson, Madsen,
l3vpn-ppvpn-terminology-04.txt, September 2004 draft-ietf-l3vpn-ppvpn-terminology-04.txt, September 2004
[LDP] "LDP Specification", Andersson, et. al., RFC 3036, Jan 2001 [LDP] "LDP Specification", Andersson, et. al., RFC 3036, Jan 2001
[PWE3-ARCH] "PWE3 Architecture", Bryant, Pate, et. al., draft-ietf- [PWE3-ARCH] "PWE3 Architecture", Bryant, Pate, et. al.,
pwe3-arch-07.txt, March 2004 draft-ietf-pwe3-arch-07.txt, March 2004
[PWE3-CONTROL] "Pseudowire Setup and Maintenance using LDP", Martini, [PWE3-CONTROL] "Pseudowire Setup and Maintenance using LDP", Martini,
et. al., draft-ietf-pwe3-control-protocol-09.txt, September 2004 et. al., draft-ietf-pwe3-control-protocol-14.txt, December 2004
[RFC2547bis], "BGP/MPLS IP VPNs", Rosen, Rekhter, et. al., draft- [PW-SWITCH] "Pseudo Wire Switching", Martini, et. al.,
ietf-l3vpn-rfc2547bis-02.txt, September 2004 draft-martini-pwe3-pw-switching-01.txt, October 2004
[RFC2547bis], "BGP/MPLS IP VPNs", Rosen, Rekhter, et. al.,
draft-ietf-l3vpn-rfc2547bis-02.txt, September 2004
[RFC2685] "Virtual Private Networks Identifier", Fox, Gleeson, [RFC2685] "Virtual Private Networks Identifier", Fox, Gleeson,
September 1999 September 1999
[VPLS] "Virtual Private LAN Services over MPLS", Laserre, et. al., [VPLS] "Virtual Private LAN Services over MPLS", Laserre, et. al.,
draft-ietf-l2vpn-vpls-ldp-05.txt, September 2004 draft-ietf-l2vpn-vpls-ldp-05.txt, September 2004
7. Author's Information Authors' Addresses
Eric C. Rosen Eric Rosen
Cisco Systems, Inc. Cisco Systems, Inc.
1414 Massachusetts Avenue 1414 Mass. Ave.
Boxborough, MA 01719 Boxborough, MA 01719
E-mail: erosen@cisco.com USA
Email: erosen@cisco.com
Wei Luo Wei Luo
Cisco Systems, Inc. Cisco Systems, Inc.
170 W. Tasman Drive 170 W Tasman Dr.
San Jose, CA 95134 San Jose, CA 95134
E-mail: luo@cisco.com USA
Email: luo@cisco.com
Bruce Davie
Cisco Systems, Inc.
1414 Mass. Ave.
Boxborough, MA 01719
USA
Email: bsd@cisco.com
Vasile Radoaca Vasile Radoaca
Nortel Networks Nortel Networks
600 Technology Park 600 Technology Park
Billerica, MA 01821 Billerica, MA 01821
Phone: (781) 856-0590/978-288-6097 USA
8. Intellectual Property Statement Phone: +1 978 288 6097
Email: vasile@nortelnetworks.com
Intellectual Property Statement
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9. Full Copyright Statement
Copyright (C) The Internet Society (2004). This document is subject Disclaimer of Validity
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 This document and the information contained herein are provided on an
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Copyright Statement
Copyright (C) The Internet Society (2005). This document is subject
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Acknowledgment
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Internet Society.
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