Subject: Re: I-D ACTION:draft-ietf-ccamp-gmpls-ason-lexicography-05.txt (fwd)

From: [email-masked]
Date: Thu, 15 Dec 2005 20:01:34 +0100

hi all

1. i still don't understand the need for the [ ... ] after each term - if
authors could clarify this would be helpful

2. in general, i don't see why this document meant to clarify GMPLS terms
for ASON includes ASON specific terms/definitions and interpretations hence
the need for each "ASON terms" sub-section is unclear

some other specifics

3. " Node [Control & Data Planes] is a logical combination of a
     transport node and the controller that manages the transport node.
     In early deployments, all control plane and data plane functions
     associated with a transport node were collocated in a node and
     referred to as a Label Switching Router (LSR)."

the second sentence is imho outside the scope of such definition

4. "3.4.1. GMPLS Terms

   Label [Control Plane] is an abstraction that provides an identifier
   for use in the control plane in order to identify a transport plane
   resource."

how to interpreet an MPLS label with this definition ? or is MPLS out of
scope ?

5. "3.5.1. GMPLS Terms

   Unidirectional data link end [Data Plane] is a set of resources of a
   particular layer that belong to the same transport node and could
   be allocated for the transfer of traffic in this layer to the same
   neighbor in the same direction."

what "same transport node" means here ?

6. " The need for advertisement of adaptation and termination capabilities
   within GMPLS has been recognized and work is in progress to determine
   how these will be advertised. It is likely that they will be
   advertised as a single combined attribute, or as separate attributes
   of the TE link local end associated with the link interface."

afaik, GMPLS is able to advertize "termination" capabilities -

thanks,
- dimitri.

---

From: "Adrian Farrel" <[email-masked]>
Date: Fri, 16 Dec 2005 23:55:36 -0000

Hi Dimitri,

Thanks for reading.

> authors could clarify this would be helpful

Hmm. Well the intention was to provide extra information in a quick way. I
guess we could replace each [...] with a full sentence such as "This term
applies to the control plane."

I suppose that the RFC editor is going to object to our use of square
brackets :-(

> the need for each "ASON terms" sub-section is unclear

The intention is not just to clarify the GMPLS terms, but also to provide
a mapping. The full purpose (of making GMPLS comprehensible to ASON
cognoscenti) is aided by the inclusion of corresponding ASON terms. What
we have done, therefore, is split the text into:
- a description of the GMPLS term
- a translation into "equivalent" ASON terms

Do you have an objection to this?

> the second sentence is imho outside the scope of such definition

Some of the GMPLS RFCs are simplified by the use of "LSR", but it has been
pointed out on numerous occasions that this creates an impression that in
GMPLS there is *always* a tight binding (collocation) between  control and
data plane functions. As you know, this impression is contrary to reality.

A couple of questions back to you.

Is what it says incorrect?
Would it help if we had a separate entry for LSR?

> how to interpreet an MPLS label with this definition ? or is MPLS out of

MPLS is out of scope because there is possible translation to ASON.

Note, however, we felt it helpful to include "Packet based resource"

> what "same transport node" means here ?

Erm?

It means "same transport node" :-)

The intention is to imply that all of the resources in the set belong to
the same transport node.

Maybe rephrase as:

  Unidirectional data link end [Data Plane] is a set of resources that
    all belong to the same transport node, all are in the same layer,
    and that could be allocated for the transfer of traffic in this
    layer to the same neighbor in the same direction."

> afaik, GMPLS is able to advertize "termination" capabilities -

Does it?
It seems to me that it advertizes switching capabilities only.
Termination, like adaptation, is not the same thing as switching
capability.

Switching capability says how the link terminates, but not whether the
node can terminate data flows.

Cheers,
Adrian