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Liaison statement
Status of Layer One VPN Work in the IETF

State Posted
Submitted Date 2005-11-30
From Group l1vpn
From Contact Adrian Farrel
To Group ITU-T-SG-13
To Contacts Georges Sebek <>
Cc Tomonori Takeda <>
Hamid Ould-Brahim <>
Scott Bradner <>
Alex Zinin <>
Bill Fenner <>
L1VPN Working Group <>
Response Contact Adrian Farrel <>
Technical Contact Adrian Farrel <>
Tomonori Takeda <>
Hamid Ould-Brahim <>
Purpose For information
Attachments (None)
The L1VPN Working Group would like to take this opportunity to inform ITU-T
Study Group 13 of its progress on the development of protocol solutions for
Layer One VPNs.

The L1VPN Working Group was chartered in the summer of this year. You can see
the details of the scope of work for the working group at

The working group is discussing two documents: presents
a framework for L1VPNs and draws much of its material from Recommendations
Y.1312 and Y.1313. The purpose of this framework is to aid in developing and
standardizing protocols and mechanisms to support interoperable L1VPNs. The
document examines motivations for L1VPNs, high level (service level)
requirements, and outlines some of the architectural models that might be used
to build L1VPNs.
provides an applicability analysis on the use of Generalized Multiprotocol
Label Switching (GMPLS) protocols and mechanisms to satisfy the requirements of
Layer 1 Virtual Private Networks (L1VPNs). In addition, this document
identifies areas where additional protocol extensions or procedures are needed
to satisfy the requirements of L1VPNs, and provides guidelines for potential
extensions. The intention is that, as new protocol extensions are developed to
meet the requirements identified here and in the framework document, this
document will convert to being a simple applicability statement.

The working group believes that these two documents are largely stable, and is
now working to develop protocol solutions for the "Basic Mode" L1VPN. This mode
of operation involves only signaling protocol exchanges (i.e. no routing)
between CE and PE in the network.

Two Internet-Drafts currently exist in support of the protocol extensions
needed for the Basic Mode as identified in the applicability draft:
describes an operational model using either provisioning or a VPN
auto-discovery mechanism and defines signaling extensions for the L1VPN Basic
defines a BGP-based auto-discovery mechanism for Layer One VPNs that allows the
provider network devices to dynamically discover the set of PEs having ports
attached to CEs member of the same VPN.

The working group is likely to adopt work items based on these Internet-Drafts
in the near future.

A further work item to provide an OSPF-based auto-discovery mechanism is being
developed but is not available at this time.

Lastly, the working group is now begining to discuss prefered solutions and
models for the "Extended Mode" of L1VPN operation that includes signaling and
routing control.

The L1VPN Working Group would like to encourage the involvement of all
interested parties through the open mailing list. Subscription details can be
found at the charter page

The review and feedback of Study Group 13 on any of this work would also be
most welcome.

Tomonori Takeda
Hamid Ould-Brahim
Adrian Farrel
(L1VPN Working Group co-chairs)