Subject: [L2CP] L2CP WG Charter draft

From: "Wojciech Dec \(wdec\)" <[email-masked]>
Date: Mon, 20 Feb 2006 09:33:47 +0100

Hi All,

Based on the feedback received, below is the amended draft charter. I
have modified it to address the investigation of the light-weight
transport. Also streamlined the deliverables.

Feedback is welcome.

Regards,
Woj.

-------------------WG CHARTER (DRAFT)------------------------

Layer 2 Control (l2c)
=====================

Current Status: Non-existing Working Group

Chair(s):
TBD <tbd>
TBD <tbd>

Internet Area Director(s):
Mark Townsley <[email-masked]>
Margaret Wasserman

Technical Advisor(s):
TBD <tbd>

Secretary(ies):
TBD <tbd>

Area Specific Mailing List:
[email-masked]

Mailing Lists:
General Discussion: [email-masked]
To Subscribe: [email-masked]
In Body: subscribe your_email_address
Archive: http://www.ietf.org/mail-archive/web/l2cp/index.html

Description of the charter for this WG:

The purpose of the L2CP WG is to standardize an IP based Layer 2 control
protocol for use in service provider access and aggregation type
networks. The protocol is to be inter-operable among a wide set of
multi-vendor devices, including but not limited to DSL Access Nodes and
Broadband Network Gateways. The rationale for introducing such a Layer 2
control protocol has been analyzed in DSL Forum Proposed Draft PD-021v2,
which was liaised to the IETF in December 2005, and sent to the IETF
GSMP discussion list in November 2004. A number of use cases have been
identified that are now progressing as an official DSL Forum working
text item. These use cases require thus specific protocol design and
extensions. 
The DSL Forum work recommends using General Switch Management Protocol
(GSMPv3) as a base protocol for Layer 2 control messages. This working
group will be responsible for investigating which subset of GSMPv3 is
required for l2c and which extensions are to be specified for the
selected use cases. It will also respond to protocol issues that arise
during implementation of the current specifications.

The goal of a Layer 2 control protocol message exchange is to convey
status and control information from access devices to one or more other
devices that require the information for executing local functions. An
example of this is the transmission of an access loop rate from the edge
access node to a Broadband Network gateway device tasked with shaping
traffic to that rate. Another goal of a Layer 2 control protocol message
exchange is to trigger a local action on access devices. An example of
this being the initiation of a local port testing mechanism.
The protocol will ensure the transmission of the information does not
need to go through distinct element managers but rather using the direct
device-device control protocol defined. This direct transmission method
is intended to offer the possibility of effecting quicker functional
changes in response to dynamic events.

Efforts of the WG will focus on addressing the following problem areas:
- Transmission of access line control and status information to network
elements tasked with coordinating policy decision and enforcement
- Reduction, through the use of the protocol, of multiple points of
access edge network element provisioning.
- Transmission of control RPCs and result messages for access node OAM
functions.

The protocol will address the information transmission requirements of
the following use-cases:

- Topology discovery
DSL Forum TR-059 identifies various queuing/scheduling mechanisms to
avoid congestion in the access network while dealing with multiple flows
with distinct QoS requirements. Such mechanisms require that the
Broadband Network gateway gains knowledge of the topology of the access
network, in particular the edge access-loop characteristics e.g. DSL
sync Rate. The l2 control protocol is intended to convey this
information. 

- Line Configuration
Following dynamic line identification (subscriber local loop) as
assisted by the mechanism described in the topology discovery case, the
Broadband Network Gateway could then query a subscriber OSS system (e.g.
RADIUS server to retrieve subscriber service profiles relating to the
subscriber line. Using an the L2 control protocol could simplify the OSS
infrastructure for service management, allowing to fully centralize
subscriber-related service data (e.g. RADIUS server back-end) and
avoiding complex cross-organization B2B interactions.

- OAM
Traditional DSL broadband access networks employ point-to-point ATM
circuits between a CPE and a BRAS. In such an environment,
troubleshooting can be achieved by means of end-to-end ATM loopbacks.
With Ethernet getting a more important role as layer 2 technology in the
aggregation network, operators require to keep ways to test and
troubleshoot connectivity in the case of a mixed Ethernet and ATM access
network (including the local loop). To reach consistency with ATM based
broadband access networks, a layer 2 control mechanism can be introduced
between a BNG and an Access Node, allowing to trigger a remote procedure
for the OAM mechanism used on the local loop.

The working group will set itself the goal to define a problem statement
allowing it to investigate and define a solution for an IP based Layer 2
control protocol that apart from fulfilling the intended usage needs is
robust, reliable and scalable. 

The L2CP WG is open to receiving new work items, whenever it is
considered appropriate to be homed in the L2CP WG. Such drafts will be
matured in conjunction with the L2CP base documents.

Goals and Milestones:

May 2006	 WG I-D of L2C Problem Statement (requirements?)
including use-cases

September 2006	 WG I-D of L2C solution and GSMPv3 extensions

December 2006 	WG I-D of L2C MIBs

March 2006	 Re-charter or conclude Working Group

Internet-Drafts:
GSMP extensions for layer2 control (L2C) - Topology Discovery and Line
Configuration <draft-wadhwa-gsmp-l2control-configuration-02.txt>

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