Internet Architecture Board


May 2005

From: on behalf of Scott W Brim
Sent: Friday, May 27, 2005 8:55 AM
Subject: [Ietf-liaisons] ITU-T NGN issues snapshot

This is a list of things going on in ITU-T NGN that the IETF should be
aware of as of the end of May (2005).

ITU-T Questions are abbreviated <question>/<studygroup>, for example
5/13 is Question 5 (OAM) of Study Group 13 (lead NGN SG).

NB this is just "NGN", including SG13 and other things with "NGN" in
the name. Other work, e.g. SG15, is not in scope. However there are
interesting things happening there, for example a "profile" is being
defined for MPLS-as-transport, as Adrian can tell you.

General summary: At this time, there is nothing I know of to be
concerned about regarding protocol enhancements or other
encroachments.  It's almost all architecture, definition of functional
elements, and some decisions about what protocols to adopt.  I do get
concerned about the architectural directions they take, and they could
use some help there, but as far as crossing boundaries into IETF
space, they aren't right now.  One boundary needs to be un-crossed
(see below).

Details ...

- Management (8/4, 5/13).  8/4 is producing M.3060, a framework for
  NGN Management.  They are almost done with the first version.  They
  will be producing something "final" in the next couple of months.  I
  know that Bert, at least, has looked through it, so it's being
  watched.  Others might want to pay attention to it too.  Sharon
  Chisholm runs 8/4 and attends IETF.  5/13 is about OAM for ATM,
  Ethernet and MPLS, focusing mainly on Ethernet these days.

- Mobility (6/13, 2/13, most of sg16, at least one question in sg11).
  They have at least one architecture for mobility and they are trying
  to generalize the entire concept while reusing old functional
  elements.  A hierarchy of mobility modes is being defined, e.g.
  "user disconnects at one device, walks across the room and uses a
  different one" is a mobility mode, as is roaming without changing IP
  address.  At the same time, they want to retain concepts like iSIM.
  I don't know of any "threats" here, and some of the players
  are sharp, but they could use some monitoring and more input.

- Requirements, Scenarios, and Functional Architecture (FGNGN wg1,
  2/13, FGNGN wg2, 3/13).

  - I hear they are producing y.ngn-accounting, which apparently uses
    IPDR instead of IPFix to gather data(?)

  - There is an assumption of IMS and the OMA framework.  While the
    definition of "NGN" in Y.2011 says services and transport are
    separate, NGN "release 1" assumes IMS is a major service
    framework, and that the main services of interest are based in the
    network provider.  For example there is an assumption that only
    one "private identity" is needed.  I'm telling them that while
    single-signon is good, that's not the only model that needs

- QoS (FGNGN wg3&4, 4/13, SG11): This includes both transport and
  service level signaling.  They seem to have an affinity with NSIS.

  Larry Roberts brought his ABR-for-TCP to 4/13, having previously
  gotten it blessed by TIA and by SG12 (who added a "conditionally
  guaranteed bandwidth" class to Y.1221).  4/13 agreed to issue a
  problem statement along the lines of Larry's proposal and allow
  contributions addressing it.

- Transition, "convergence", and MPLS Interworking (7/13, 12/13, 4/11,
  5/13).  This is about interworking of MPLS with all the other
  transport mechanisms out there -- ATM, FR, TDM, etc.

  - 7/13 covers all three planes, control/mgmt/user,  but is mainly
    focused on user plane.  7/13 put out the Y.141x series, which were
    meant to be the PWE3 encapsulations, before they were ready, and
    changed all the terminology as they did so.  I expect Y.141x to be
    reissued once the PWE3 encapsulations make it through RFC Editor.
    However, let's not push for that until 7/13 makes progress on the
    "general framework" for interworking (I'm involved there).

  - 12/13 is strictly a reflection of what's going on in the MFA
    Forum, for ATM and FR control interworking with MPLS pseudowire
    signaling and possibly BGP -- the activity to watch is in MFA, and
    they're pretty good about bringing things to the IETF.  The only
    thing to be concerned about is if MFA are driven to ask for IETF
    changes due to compromises in ITU-T.  So far so good.

  - MPLS and other transport OAM is mainly done in 5/13 but some
    interworking is covered in 7/13.  Right now they are focused on
    OAM for Ethernet-as-transport.  4/11 advises on signaling
    interworking issues, to make sure the interworking supports the
    needed functions.

- IPv6 (9/13).  The charter is "the impact of IPv6 on NGNs".  For a
  while I was concerned because they seemed to be recommending a
  subset scenario, for example to use SCTP for mobility.  They backed
  off from that.  This is the general issue in a nutshell, for ITU-T
  use of IETF protocols for NGN: they are trying to apply IETF
  products in a particular scenario and could use some advice from the
  experts doing so.

That's it for now ... swb