RE: IETF CCAMP Respons to OIF on Inter-Level Routing

["Ong, Lyndon" <Lyong@Ciena.com>]

Dear Adrian and Deborah,

Thank you for the series of liaison responses, OIF will review them in
our 1Q09 meeting in January.  As always, we appreciate CCAMP's time and
attention.

Wishing everyone Happy Holidays and a productive New Year!

Best regards,

Lyndon Ong
OIF Technical Committee Chair



-----Original Message-----
From: Adrian Farrel [mailto:adrian@olddog.co.uk] 
Sent: Monday, December 22, 2008 1:59 PM
To: Ong, Lyndon; Lucille Goldiner
Cc: Brungard, Deborah A, ALABS; ccamp@ops.ietf.org
Subject: IETF CCAMP Respons to OIF on Inter-Level Routing

Dear Lyndon,

 Here is a final response to the issues raised by the OIF. This one
relates 
to ASON routing and multi-layer networks, and comes from your
communication 
oif2008.063.02.pdf.

> in our discussions of multilayer networks and impacts on the control 
> plane, we took note of ITU-T Recommendation
> G.7715.1 requirements to advertise:
> a) Local Connection Type; and
> b) Local Client Adaptations Supported.
> We believe that this functionality would be very useful for
> applications that have been discussed in OIF (see
> attachment). We would appreciate further clarification as to
> whether both requirements have been addressed in the current
> CCAMP work on ASON routing support (local connection type in
> particular is not explicitly identified in the current draft). We
would 
> also appreciate more information on the
> relationship between support of adaptation in the ASON routing draft
and 
> in the multilayer/multiregion networking
> drafts also being developed in the CCAMP WG.

 We note that G.7715.1 discusses the operation of multi-layer networks
in an 
appendix and observes:

   This appendix provides illustrative examples of different
   methods of carrying multiple layer information between two
   systems. It does not mandate a particular method of
   implementation for link state routing protocols.

   From the perspective of ITU-T Rec. G.8080/Y.1304, each layer
   network has its own instance of a control plane.

 It can also be observed that a single routing level cannot span
multiple 
network layers within the ASON architecture.

 draft-ietf-ccamp-gmpls-ason-routing-ospf-06.txt addresses the
distribution 
of routing information between Routing Areas (in the ASON sense), but is

agnostic to the routing information passed. For more details of the
exchange 
of "local connection type" and "local client adaptations" we need to
look 
into the base GMPLS routing specifications and the CCAMP work on
multi-layer 
networks.

As pointed out in RFC 4652, the Switching Capability field of the
Interface 
Switching Capability Descriptor (see RFC 4202) describes the
capabilities of 
the receiver with regard to any specific TE link (e.g., PSC, TDM, etc.).

Your question also opens up the issue of distinguishing between what
signal 
types an LSR can terminate (through adaptation) as distinct from switch 
(onto another TE link). This function is addressed in another CCAMP
draft, 
draft-ietf-ccamp-gmpls-mln-extensions-03.txt, which will go to CCAMP
working 
group last call soon. This draft introduces the Interface Adaptation 
Capability Descriptor (IACD) to carry the necessary information.

Both the ISCD and the IACD can be exchanged between routing levels using
the 
techniques described in draft-ietf-ccamp-gmpls-ason-routing-ospf-06.txt.
You 
may, however, also like to look at the appropriateness of the PCE 
architecture (RFC 4655) in the role of inter-level routing as it seems
to 
fit well with the architecture as described by the ITU-T in G.7715.2.

Best regards,
Adrian Farrel and Deborah Brungard
IETF CCAMP Working Group Co-Chairs