One document matched: draft-luo-l2tpext-l2vpn-signaling-01.txt
Differences from draft-luo-l2tpext-l2vpn-signaling-00.txt
Network Working Group Wei Luo
Internet Draft Cisco Systems, Inc.
February 2003
L2VPN Signaling Using L2TPv3
draft-luo-l2tpext-l2vpn-signaling-01.txt
Status of this Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
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and may be updated, replaced, or obsoleted by other documents at any
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The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
Abstract
The Layer 2 Tunneling Protocol (L2TPv3) provides a standard method
for setting up and managing L2TP sessions to tunnel a variety of L2
protocols. One of the reference models supported by L2TPv3 describes
the use of an L2TP session to cross-connect two Layer 2 circuits
attached to a pair of peering LACs. A cross-connect is a basic form
of Layer 2 Virtual Private Networks (L2VPNs). This document
describes mechanisms which utilize the building blocks that L2TP
provides to construct different types of L2VPNs.
Specification of Requirements
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC 2119].
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Table of Contents
Status of this Memo.......................................... 1
1. Introduction.............................................. 3
2. Network Reference Model and L2VPN Applications............ 3
3. Forwarders and End Identifiers............................ 4
4. L2TP Control Messages..................................... 5
5. Existing AVPs for L2VPNs.................................. 5
5.1 Router ID............................................. 5
5.2 Pseudowire Capabilities List.......................... 5
5.3 Pseudowire Type....................................... 5
5.4 Pseudowire Control Encapsulation...................... 6
5.5 Circuit Status........................................ 6
5.6 Remote End ID......................................... 6
6. New AVPs for L2VPN........................................ 6
6.1 Local End ID.......................................... 6
7. Pseudowire Tie Detection.................................. 7
8. L2VPN Signaling Procedures................................ 8
8.1 Overview.............................................. 8
8.2 Generic Algorithm..................................... 8
8.3 Application-specified Processing...................... 12
8.3.1 Cross-connect.................................... 12
8.3.2 Virtual Private LAN Service...................... 12
8.3.3 Colored Pools.................................... 13
9. BGP-based Auto-discovery.................................. 13
9.1 Common L2VPN Addressing and NLRI Encoding............. 13
9.2 AFI/SAFI and BGP Capabilities......................... 14
9.3 Route Targets......................................... 14
10. Heterogeneous L2VPN Deployment........................... 15
11. Intellectual Property Notice............................. 16
12. IANA Considerations...................................... 16
13. Security Considerations.................................. 16
14. Acknowledgement.......................................... 16
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15. References............................................... 16
16. Authors' Address......................................... 17
1. Introduction
[L2TPv3] defines a dynamic tunneling mechanism to carry multiple L2
protocols besides PPP (as originally defined in [RFC 2661]), over a
packet-based network. The baseline protocol supports various types
of applications, which has been hightlighted in the different L2TP
reference models in [L2TPv3]. L2VPN applications are typically in
the scope of the LAC-LAC reference model.
This document discusses the commonality as well as difference among
L2VPN applications with respect to utilizing L2TPv3 as the signaling
protocol. It also specifies the necessary information required by
BGP-based auto-discovery for the integration with the L2TPv3-based
signaling protocol. Other auto-discovery mechanisms are left for
future studies.
The acronym "L2TP" refers to L2TPv3 or L2TP in general in this
document.
2. Network Reference Model and L2VPN Applications
In the LAC-LAC reference mode, a LAC serves as a cross-connect
between attachment circuits and L2TP sessions. Each L2TP session
acts as an emulated circuit, also known as pseudowire.
+-----+ L2 +-----+ +-----+ L2 +-----+
| |------| LAC |...[packet network]...| LAC |------| |
+-----+ +-----+ +-----+ +-----+
remote remote
system system
|<- emulated service ->|
|<----------------- L2 service ----------------->|
In a simple cross-connect application, an attachment circuit is
directly bound to a pseudowire. It's a one-to-one mapping. Traffic
received from the attachment circuit on a local LAC is forwarded to
the remote LAC through the pseudowire. When the remote LAC receives
traffic from the pseudowire, it forwards the traffic to the
corresponding attachment circuit on its end. The forwarding decision
is based on the attachment circuit or pseudowire demultiplexing
identifier respectively.
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With Virtual Private LAN Service (VPLS), one or more attachment
circuits and pseudowires are connected to a Virtual Switching
Instance (VSI) on a LAC. A single pseudowire is used to connect a
pair of VSIs on two peering LACs. Traffic received from an
attachment circuit or a pseudowire is first forwarded to the
corresponding VSI based on the attachment circuit or pseudowire
demutiplexing identifier. The VSI performs additional lookup to
determine where to further forward the traffic.
[L2 FW] describes an L2VPN application called Colored Pools, which is
essentially made of a network of point-to-point cross-connect. The
data forwarding perspective is identical to the cross-connect
application, while constructing Colored Pools involves more
complicated signaling procedures.
3. Forwarders and End Identifiers
As described in [L2 FW], a pseudowire is bound to a "forwarder",
which in turn binds to one or more attachment circuits. For
different L2VPN applications, different types of forwarders are
defined.
An End Identifier is assigned to each forwarder on a given LAC that
supports L2VPN applications. It must be unique in the context of the
LAC.
In simple cross-connect, each individual attachment circuit is a
forwarder, and provisioned with an End ID value. Without any auto-
discovery, each attachment circuit needs to be manually provisioned
with the remote Router ID and the End ID of the remote attachment
circuit. The End ID value for an attachment circuit may be an
arbitrary integer or a descriptive string.
In VPLS, each VSI is a forwarder, and provisioned with an End ID
value. Without any auto-discovery, each VSI needs to be manually
provisioned with its remote LAC addresses and the End IDs of the
remote VSIs. The End ID value for a VSI may be the VPN ID of the
VPLS domain.
In Colored Pools, each pool is a forwarder, and provisioned with an
End ID value. Without any auto-discovery, each pool needs to be
manually provisioned with its remote LAC addresses and the End IDs of
the remote pools. The End ID value for a pool may be an arbitrary
integer or a descriptive string.
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4. L2TP Control Messages
L2TP defines two sets of session management procedures: Incoming Call
and Outgoing Call. Even though it's entirely possible to use the
Outgoing Call procedures to signaling L2VPNs, the Incoming Call
procedures has some advantages in terms of the relevance of semantics
and being able to offer moderate capability negotiation between two
LCCEs. [PWE3L2TP] gives more details on why Incoming Call is more
appropriate for setting up pseudowires.
The signaling procedures for L2VPNs described in the following
sections are all based on the Incoming Call procedures.
5. Existing AVPs for L2VPNs
Besides the AVPs required to establish and manage control connections
and sessions, the following AVPs defined in [L2TPv3] are directly
relevant to L2VPN applications.
5.1 Router ID
The Router ID sent in SCCRQ and SCCRP during control connection setup
establishes the unique identity of each LAC.
5.2 Pseudowire Capabilities List
The Pseudowire Capabilities List sent in SCCRQ and SCCRP indicates
the pseudowire types supported by the sending LAC. It merely serves
as an advertisement to the receiving LAC. Its content should not
affect the control connection setup.
Before a local LAC initiates a session of a particular pseudowire
type to a remote LAC, it MUST examine whether the remote LAC has
advertised such a capability in this AVP, and SHOULD NOT attempt to
initiate the session if the intended pseudowire type is not supported
by the remote LAC.
5.3 Pseudowire Type
The Pseudowire Type sent in ICRQ signals the intended pseudowire type
to the receiving LAC. The receiving LAC checks it against its local
pseudowire capability list. If it finds a match, it responds with an
ICRP without a Pseudowire Type AVP, which implicitly acknowledges its
acceptance of the intended pseudowire. If it does not find a match,
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it MUST respond with a CDN with an "unsupported pseudowire type"
result code.
5.4 Pseudowire Control Encapsulation
The Pseudowire Control Encapsulation can be sent in ICRQ, ICRP, and
ICCN. If the receiving LAC supports the specified control
encapsulation, it MUST include it in its data packets sent to the
sending LAC. Otherwise, it MUST reject the connection by sending a
CDN to the sending LAC.
5.5 Circuit Status
The Circuit Status is sent in both ICRQ and ICRP to inform the
receiving LAC about the circuit status on the sending LAC. It can
also be sent in ICCN and SLI to update the status.
5.6 Remote End ID
The Remote End ID sent in ICRQ instructs the receiving LAC to bind
the proposed pseudowire to the forwarder that has been assigned with
the encoded End Identifier value.
6. New AVPs for L2VPN
6.1 Local End ID
The Local End ID AVP, Attribute Type TBA, encodes the End Identifier
value of the forwarder to be bound to the proposed pseudowire on the
sending LAC. The Local End ID AVP may also be used in conjunction
with the Remote End ID AVP to detect session-level ties. When it's
omitted in the control messages, it's assumed that it has the same
value as the Remote End ID.
The Attribute Value field for this AVP has the following format:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|M|H|0|0|0|0| Length | 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TBA | End ID ... (variable length) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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The End Identifier field is a variable-length field whose value is
unique for a given LCCE. This AVP MAY be present in ICRQ.
This AVP MAY be hidden (the H bit MAY be 0 or 1). The M bit for this
AVP SHOULD be set to 0. The Length (before hiding) of this AVP is 6
plus the length of the End Identifier value.
7. Pseudowire Tie Detection
Conceivably in the LAC-LAC network reference model, as either LAC may
initiate a session to another LAC at any time, they could end up
initiating a session to each other simultaneously.
In order to avoid setting up duplicated pseudowires between two
forwarders, each LAC must be able to independently detect such a
pseudowire tie. The following procedures need to be followed to
detect a tie:
If both Remote End ID and Local End ID are present in ICRQ, the
receiving LAC compares them with the Remote End ID and Local End ID,
in reverse order, encoded in the ICRQ it has already sent to the
sending LAC. If the received Remote End ID matches the sent Local
End ID and the received Local End ID matches the sent Remote End ID,
a tie is detected.
If only Remote End ID is present in ICRQ, the Local End ID is assumed
to have the same value as the Remote End ID. The receiving LAC
compares the received Remote End ID with the Local End ID, encoded in
the ICRQ it has already sent to the sending LAC. If the Local End ID
in this ICRQ is also omitted, then the Remote End ID is compared. If
they match, a tie is detected.
Once a tie has been discovered, the standard L2TP tie breaking
procedure is employed to disconnect the duplicated pseudowire.
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8. L2VPN Signaling Procedures
8.1 Overview
Assume a LAC assigns an End ID to one of its local forwarders, and
knows it needs to set up a pseudowire to a remote forwarder on a
remote LAC that has a certain End ID. This knowledge can be obtained
either through manual configuration or some auto-discovery procedure.
Before establishing the intended pseudowire, each pair of peering
LACs exchanges control connection messages to establish a control
connection. Each advertises its supported pseudowire types in the
Pseudowire Capabilities List AVP.
After the control connection is established, the local LAC examines
whether the remote LAC supports the pseudowire type it intends to set
up. Only if the remote LAC supports the intended pseudowire type, it
should initiate a pseudowire connection request.
When the local LAC receives an ICRQ for a pseudowire connection, it
examines the Remote End ID encoded in the ICRQ to determine the
following:
- whether it has a local forwarder assigned with an End ID value
specified in the Remote End ID,
- whether the remote LAC is allowed to connect with this local
forwarder.
If both conditions are met, it sends an ICRP to the remote LAC to
accept the connection request. If either of the two conditions
fails, it sends a CDN to the remote LAC to reject the connection
request.
8.2 Generic Algorithm
Despite the apparent disparity among different L2VPN applications, a
common set of signaling procedures can be defined.
Each LAC first forms a list, SOURCE_FORWARDERS, consisting of all
local forwarders of a given VPN. Then it puts all local forwarders
that need to be interconnected and all remote forwarders of the same
VPN into another list, TARGET_FORWARDERS. The formation of the
network topology depends on the content in the SOURCE_FORWARDERS and
TARGET_FORWARDERS list. These two lists can be constructed by manual
configuration and/or some auto-discovery procedure.
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The following algorithm is used to set up pseudowires among all the
forwarders that intend to be interconnected by iterating through each
source and target forwarder. An L2VPN is formed upon finishing the
algorithm in every LAC participating in L2VPN.
SOURCE_FORWARDERS TARGET_FORWARDERS
s1: <Router ID, End ID> t1: <Router ID, End ID>
s2: <Router ID, End ID> t2: <Router ID, End ID>
s3: <Router ID, End ID> t3: <Router ID, End ID>
... ...
1. Pick the next forwarder, from SOURCE_FORWARDERS. If no
forwarder is available for processing, the processing is
complete.
2. Pick the next forwarder, from TARGET_FORWARDERS. If no
forwarder is available for processing, go back to step 1.
3. If the two forwarders are associated with different Router IDs,
a pseudowire must be setup between them. Proceed to step 6.
4. Compare the End ID values of the two forwarders, if they match,
the source and target forwarders are the same, so no more
action is necessary. Go back to step 2.
5. As the source and target forwarders both reside on the local
LAC, no pseudowire is needed. LAC simply creates a local
cross-connect between the two forwarders. Go back to step 2.
6. As the source and target forwarders reside on different LACs,
a pseudowire must be established between them. LAC first
examines if the source forwarder has already established a
pseudowire to the target forwarder. If so, go back to step 2.
7. If no pseudowire is already established between the source and
target forwarders, the local LAC obtains the address of the
remote LAC, and establishes a control connection to the remote
LAC if one does not already exist.
8. The local LAC sends an ICRQ to the remote LAC. The End IDs of
source and target forwarders are encoded as the Local End ID
and Remote End ID respectively.
9. If the local LAC receives a response corresponding to the
ICRQ it just sent, proceed to step 10. Otherwise, if the
local LAC receives an ICRQ from the same remote LAC, proceed
to step 11.
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10. The local LAC receives a response from the remote LAC. If
it's a CDN, go back to step 2. If it's an ICRP, the local
LAC binds the source forwarder to the pseudowire and sends
an ICCN to the remote LAC, go back to step 2.
11. If the local LAC receives an ICRQ from the same remote LAC,
it needs to perform session tie detection, as described in
Section 7. If a session tie is detected, it performs tie
breaking.
12. If it lost in tie breaking, the local LAC sends a CDN with
the result code that indicates the disconnection is due to
losing tie breaker. Proceed to step 14.
13. If it won in tie breaking, the local LAC ignores the remote
LAC's ICRQ (note that the L2TP reliable transport confirms
receipt of the message with any legitimate control message
even though it doesn't respond to the ICRQ), and continues
waiting for the response from the remote LAC. Go to step 10.
14. The local LAC determines whether it should accept the
connection request, as described in the section 8.1.
If it accepts the ICRQ, it sends an ICRP to the remote LAC.
15. The local LAC receives a response from the remote LAC. If
it's a CDN, go back to step 2. If it's an ICCN, the local
LAC binds the source forwarder to the pseudowire, go back
to step 2.
The following diagram illustrate the above procedures:
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---------> Pick Next
| Source Forwarder
| |
| |
| v N
| Found Source Forwarder? ----------> End
| |
| Y |
| v
| Pick Next <--------------------------------
| Target Forwarder |
| | |
| | |
| N v |
-------- Found Target Forwarder? |
| |
Y | |
v Y Y |
Same Router ID? -----------> Same End ID? -------|
| | |
N | N | |
| v |
| Create Local -------|
v Cross-connect |
Pseudowire Already Y |
Established Between -------------------------------|
Source and Target? |
| |
N | |
v |
Local Initiates Pseudowire |
Connection Request to Remote |
| |
| |
v |
-------> Local Wait for Message |
| ----- from Remote -------------- |
| | | |
| | | |
| v v |
| Local Receives Pseudowire Local Receives Pseudowire |
| Connection Request Connection Response |
| from Remote from Remote |
| | | |
| | | |
| v v N |
| Perform Pseudowire Connection Accepted? --------|
| Tie Detection | |
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| | Y | |
| | v |
| | Local Binds Source ---------|
| | Forwarder to Pseudowire |
| | |
| v N N |
| Tie Detected? -----> Accept Remote -----> Reject ------|
| | Connection Request? Remote Request |
| Y | ^ | |
| v | | Y |
| Perform Tie Breaking | ------> Local Binds ----
| | | Source Forwarder
| | | to Pseudowire
| v N |
| Won Tie Breaking? ------> Disconnect
| | Local Connection
| Y |
| v
------ Ignore Remote
Connection Request
8.3 Application-specified Processing
8.3.1 Cross-connect
When a LAC learns the remote Router ID and remote End ID, it may
start the signaling right away or wait for the circuit status of the
local attachment circuit to become active.
After the pseudowire has been successfully established, a LAC binds
the attachment circuit to the pseudowire.
8.3.2 Virtual Private LAN Service
A VSI is a forwarder in VPLS and consists of a number of attachment
circuits and a number of pseudowires. A LAC may have multiple VSIs.
When a LAC learns the remote Router IDs and remote End IDs, it may
start the signaling right away or wait for the first attachment
circuit to join the local VSI.
After the pseudowire has been successfully established, a LAC binds
the VSI to the pseduowire by making the pseudowire a member link of
the bridging domain defined by the VSI.
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8.3.3 Colored Pools
In the LAC-LAC network reference model, a remote system may have
multiple physical or logical attachment circuits, such as Frame Relay
DLCIs attached to a LAC, which form a "pool" of attachment circuits.
Each pool corresponds to a particular remote system, and is
associated with a particular VPN. If there are multiple remote
systems of the same VPN attached to a LAC, the LAC will have multiple
pools associated with the same VPN.
Each pool is provisioned with an End ID that differentiates itself
from other forwarders residing in the same LAC, and a "color", which
represents a particular VPN. The format of "color" can be a VPN ID.
A VPN ID can be an unsigned integer or a structured numeric value.
If pools with a certain color need to be connected in a full-mesh
fashion, a pseudowire is created between every pair of pools except
the pools residing on the same LAC, and the pseudowire is bound to an
unused attachment circuit from each pool. For pools on the same LAC,
a local cross-connect is formed to bind two attachment circuits.
9. BGP-based Auto-discovery
The BGP-based auto-discovery specified in this document is similar to
the schemes described in [BGPVPN] and [LDPVPN], but further
optimized. Although this mechanism is only discussed in the L2TP
context, it's conceivably useful for LDP-based L2VPN signaling as
well.
9.1 Common L2VPN Addressing and NLRI Encoding
As outlined in Section 3, each forwarder is assigned with an End
Identifier value. An End ID is locally significant and unique
regardless what type of forwarder it's associated with. A Router ID
is a 32-bit global unique value. A Common L2VPN Address is defined
as the concatenation of Router ID and End ID.
The Network Layer Reachability Information (NLRI) for BGP
Multiprotocol Extension [RFC 2858] is encoded as one or more tuples
of the form <length, prefix>:
- Length: 1 octet
The Length field indicates the length in bits of the common
L2VPN address.
- Prefix: variable-length
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The Prefix fields carry the Common L2VPN Address. As the
Router ID is 32 bits in length, the maximum length of the
End ID is 223 bits, which is rounded to 27 whole octets.
When using BGP-based auto-discovery, care needs to be taken to ensure
the End ID values assigned to the local forwarders do not exceed the
maximum length allowed.
Unlike the NLRI encoding described in [BGPVPN] and [LDPVPN], the
Common L2VPN Addressing scheme uses a single format for all L2VPN
applications, and no Route Distinguisher is needed to guarantee the
uniqueness of the prefix, as a Common L2VPN Address is globally
unique by definition.
9.2 AFI/SAFI and BGP Capabilities
An AFI, to be assigned by IANA, is used for all L2VPN applications.
When L2VPN applications choose to use the Common L2VPN Addressing
scheme, an SAFI, to be assigned by IANA, is used to identify that the
NLRI carried in BGP has such an address format.
In order for two BGP speakers to exchange Common L2VPN NLRI, they
MUST use the negotiation scheme defined in [RFC 2842] to ensure that
both of them are capable of processing such NLRI correctly. This is
done by using the Capability Code 1 for Multiprotocol Extensions, and
the Capability Value containing the AFI and SAFI specified in this
document. The format of the Capabilities parameter is defined in
[RFC 2858].
9.3 Route Targets
If a forwarder wishes to be discovered via BGP, it needs to create a
Common L2VPN Address, and associate the address with one or more
Route Target (RT) Extended Community attributes [BGPEXT]. These
attributes are carried in BGP as part of the Path Attributes, along
with the LAC itself as the BGP next hop.
RTs are used in BGP to control the NLRI distribution. Each BGP
speaker can define a set of distribution policies using RTs to
control how addresses are advertised and learnt, thereby governing
the formation of the L2VPN network topology.
To form a full mesh among the forwarders that belong to the same VPN,
each forwarder is configured with the same RT value as both the
"export RT" and "import RT". This distribution policy will allow
these forwarders to be visible to all BGP speakers having this
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policy. Therefore, the L2VPN signaling will set up a full mesh of
pseudowires among these forwarders using the algorithm described the
previous section.
Sometimes, a hub-and-spoke L2VPN network is desired. This can be
achieved by using two different RTs for distribution processing,
where one stands for "hub" and the other stands for "spoke". On the
hub LAC, the "hub" RT is assigned to local forwarders as the "export
RT", and the hub LAC is configured to "import" only the Common L2VPN
addresses that have the "spoke" RT. On the spoke LAC, the "spoke" RT
is assigned to local forwarders as the "export RT", and the spoke LAC
is configured to "import" only the Common L2VPN addresses that have
the "hub" RT. This distribution policy will result in (1) spoke LACs
only seeing the forwarders configured on the hub LAC, and (2) a hub
LAC seeing all forwarders configured on every spoke LAC. The L2VPN
signaling then sets up pseudowires that form the hub-and-spoke
topology.
A more complex topology is partial mesh. It can be done by using a
set of "import RTs" and "export RTs" for distribution processing.
10. Heterogeneous L2VPN Deployment
Often there is more than one form of L2VPN application required in a
network. For example, an individual attachment circuit on one LAC
needs to be connected to a VSI or Colored Pool on another LAC by a
pseudowire. In such a case, different L2VPN applications are
deployed concurrently and different types of forwarders are inter-
connected by pseudowires.
The use of Common L2VPN Addressing makes this mix-and-match L2VPN
deployment scenario feasible and easy to manage. As forwarders are
addressed in the same fashion despite different forwarding behaviors
that each may have, a common set of signaling and auto-discovery
procedures can be implemented for a heterogeneous L2VPN deployment.
In addition, the forwarding behavior of each forwarder is determined
by its local characteristics, not those of its peer forwarder. This
gives great flexibility to deploy a heterogeneous L2VPN.
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11. Intellectual Property Notice
The IETF has been notified of intellectual property rights claimed in
regard to some or all of the specification contained in this
document. For more information consult the online list of claimed
rights.
12. IANA Considerations
This document defines a new L2TP AVP and a pair of AFI/SAFI to be
maintained by the IANA.
13. Security Considerations
The signaling procedures described in this document does not incur
additional security considerations that L2TP already provisions.
14. Acknowledgement
Many thanks to Mark Townsley, Jed Lau and Dmitry Bokotey for their
review and insightful feedback.
15. References
[RFC 2661] W. Townsley et. al., "Layer 2 Tunnel Protocol (L2TP)",
RFC 2661, August 1999.
[L2TPv3] J. Lau et. al., "Layer Two Tunneling Protocol (version3)",
draft-ietf-l2tpext-l2tp-base-04.txt, November 2002
[L2 FW] L. Andersson et. al., "PPVPN L2 Framework",
draft-ietf-ppvpn-l2-framework-00.txt, August 2002
[PWE3L2TP] W. Townsley, "Pseudowires and L2TPv3",
draft-townsley-pwe3-l2tpv3-00.txt, June 2002
[BGPVPN] H. Ould-Brahim et. al. "Using BGP as an Auto-Discovery
Mechanism for Network-based VPNs",
draft-ietf-ppvpn-bgpvpn-auto-03.txt, August 2002
[LDPVPN] E. Rosen, "LDP-based Signaling for L2VPNs",
draft-rosen-ppvpn-l2-signaling-02.txt, September 2002
[RFC 2858] T. Bates et. al., "Multiprotocol Extensions for BGP-4",
Luo [Page 16]
Internet Draft draft-luo-l2tpext-l2vpn-signaling-01.txt February 2003
RFC 2858, June 2000
[RFC 2842] R. Chandra et. al., "Capabilities Advertisement with
BGP-4", RFC2842, May 2000
[BGPEXT] S. Sangli et. al., "BGP Extended Communities Attribute",
draft-ietf-idr-bgp-ext-communities-05.txt, May 2002
16. Authors' Address
Wei Luo
Cisco Systems, Inc.
170 West Tasman Drive
San Jose, CA 95134
Email: luo@cisco.com
Luo [Page 17]
| PAFTECH AB 2003-2026 | 2026-04-21 13:27:59 |