Subject: [ANCP] Updates to ANCP charter

From: "BOCCI Matthew" <[email-masked]>
Date: Tue, 17 Feb 2009 16:15:24 +0100

All

There has been some interest shown in expanding the scope of ANCP to
include PON. However, our charter up until now has been pretty specific
about focussing on DSL. 

We would therefore like to propose some updates to the charter to allow
ANCP to develop extensions for other technologies apart from DSL. We
also need to revise our goals and milestones to reflect the latest
status of the multicast work.

Please find attached a draft revised charter. Please can you post any
comments to the list by the end of the February to give us time to make
any updates before the next IETF.

Best regards

Matthew & Woj

Description of Working Group:

Purpose:

The purpose of the ANCP WG is to standardize an IP based Access Node 
Control Protocol (ANCP) for use in service provider broadband access and
aggregation 
networks e.g. Digital Subscriber Line (DSL) and Passive Optical Network
(PON). ANCP operates between an 
Access Node (AN) and Network Access Server (NAS). 

Necessary Terminology:

Access Node (AN) - Network device, usually located at a service 
provider central office or street cabinet, that terminates access loop 
connections from Subscribers. In DSL, this is often referred to as a 
Digital Subscriber Line Access Multiplexer (DSLAM). In PON, this is
usually comprised of an Optical Network Termination (ONT) and an Optical
Line Termination (OLT).

Network Access Server (NAS) - Network device which aggregates 
multiplexedSubscriber traffic from a number of Access Nodes. The NAS 
plays a central role in per-subsciber policy enforcement and QoS. 
Often referred to as a Broadband Network Gateway (BNG) or Broadband 
Remote Access Server (BRAS). A detailed definition of the NAS is given 
in RFC2881.

Goals:

ANCP is intended to address the requirement for a bidirectional, IP-
based, control protocol that operates across multiple types (i.e., 
Ethernet, ATM) of DSL and PON access and aggregation networks. The goal
of an 
ANCP message exchange is to convey status and control information 
between one or more ANs and one or more NASs without going through 
intermediate element managers. 

The ANCP WG will address the following four use-cases:

1. Dynamic Access Loop Attributes
Various queuing and scheduling mechanisms are used in access networks 
to avoid congestion while dealing with multiple flows and distinct QoS 
profiles. Communicating the access-loop status, attributes and current 
DSL synchronization rate between the AN and Subscriber up to the NAS 
is desirable, particularly when the NAS is providing QoS for 
individual flows and subscribers. ANCP will provide a mechanism to 
communicate dynamic access-loop attributes from the AN to the NAS.

2. Access Loop Configuration
In additional to reporting Access Loop characteristics from the AN to 
the NAS, ANCP will allow a NAS to send loop-specific configuration 
information to an AN based on the results of subscriber authentication 
and authorization (e.g., after AAA responses have been received at the 
NAS). 

3. Remote Connectivity Test
Traditional DSL access and aggregation networks employ point-to-point 
ATM circuits between the AN and NAS for each subscriber, allowing 
troubleshooting of the local loop from the NAS via ATM OAM tools. With 
the increasing deployment of Ethernet in the access and aggregation 
network, operators require consistent methods to test and troubleshoot 
connectivity for mixed Ethernet and ATM access networks (including the 
local loop). ANCP will allow a remote procedure for a local loop 
connectivity test to be triggered from the NAS with results 
communicated back to the NAS. 

4. Multicast
When multicast replication for subscriber-bound traffic is performed at
the AN, it offloads the network between the AN and NAS. However, a
subscriber's policy and configuration for multicast traffic may only be
known at the NAS. ANCP will provide a mechanism to communicate the
necessary information exchange between the AN and NAS so as to allow 
the AN to perform subscriber bound multicast group replication in line 
with the subscriber's policy and configuration, and also allow the NAS 
to follow each subscriber's multicast group membership.

Non-Goals:

ANCP is an IP-based protocol that operates between the AN and NAS, 
over a broadband access and aggregation network. It will not address
setup 
or configuration of circuits or connections in the access and 
aggregation network itself.

The focus of this WG is on one very specific application space. While 
the design of the protocol must be general as to not preclude other 
uses in the future should a need arise, it is not a goal of this WG
to address specific requirements outside of broadband access and
aggregation 
networks. 

Security:

The ANCP working group will provide a threat analysis and address the 
associated security aspects of the control protocol. 

Resiliency and Scalability: 

A graceful restart mechanism will be defined to enable the protocol to 
be resilient to network failures between the AN and NAS.

Scalability at the NAS is of primary concern, as it may be aggregating 
traffic from a large number of ANs, which in turn may be serving a 
large number of Subscribers. ANCP traffic should not become a denial 
of service attack on the NAS control plane. Format of messages, 
pacing, transport over UDP or TCP, etc. will be considered with this 
in mind.

For reasons of aggregation network scalability, some use cases require 
that aspects of NAS or AN functionality may be distributed in nodes in 
the aggregation network. In these cases, ANCP can run between these 
nodes.

Deliverables:

The working group will define a basic framework and requirements 
document intended for Informational publication, focusing on the four 
use-cases outlined in this charter. This document will include a 
security threat analysis and associated requirements. The WG will then 
investigate and define a solution for an IP based control protocol 
meeting these requirements. 

There are early interoperable implementations of an ANCP-like protocol 
which are based on an extended subset of the GSMPv3 protocol. This 
running code will be the starting point for the working group 
solution, and will be abandoned only if the WG determines it is not 
adequate to meet requirements going forward.

Coordination with other Working Groups or Organizations:

The working group will coordinate with the ADSL MIB working group so 
the management framework and MIB modules are consistent for DSL 
access environments. The working group will re-use, as far as 
possible, standard MIB modules that have already been defined.

The working group will coordinate with the Broadband Forum to ensure
that 
ANCP meets the requirements of broadband access networks.

The remote connectivity test use case may require coordination with 
ITU-T Ethernet OAM work, and with IEEE 802.1ag.
Goals and Milestones:
Done	  	Accept WG I-D for ANCP Framework and Requirements 
Done	  	Accept WG I-D for Access Node Control Protocol (ANCP) 
Done	  	Accept WG ID for Security Threats analysis 
Done	  	Accept WG I-D for ANCP MIB 
Done	  	Security Threats Analysis last call 
Mar 2008  	ANCP MIB Last Call 
Done  	Framework and Requirements last call 
Mar 2009	Accept WG I-D for Additional Multicast Extensions
Mar 2009	Accept WG I-D for ANCP applicability to PON
Aug 2009   	Access Node Control Protocol (ANCP) Last Call 
Dec 2009	Additional Multicast Extensions Last Call
Dec 2009  	Re-charter or conclude Working Group

---

From: Tom Taylor <[email-masked]>
Date: Thu, 26 Feb 2009 11:44:27 -0500

I'll express my support for the updated charter. I may have time before the 
deadline to do a survey of technology-specific aspects of the current protocol 
specification that need amendment to include PON. This would just be a working 
document, not intended to be a WG deliverable.

Tom Taylor

BOCCI Matthew wrote:
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