Subject: [CCAMP] Moving WSON Routing Drafts to Last Call

From: Greg Bernstein <[email-masked]>
Date: Sat, 02 Apr 2011 21:21:32 +0200

Hi CCAMPers and, in particular, WSON interested parties. At the Prague 
meeting we put forward a request to move the following drafts to last call:
(1) Routing and Wavelength Assignment Information Model for WSON
(2) General Network Element Constraint Encoding for GMPLS Controlled
(3) Routing and Wavelength Assignment Information Encoding for WSON
(4) OSPF Enhancement for Signal and Network Element Compatibility for WSON

A presentation following ours suggested that further optimization could 
be done with respect to "Link Sets" and "Resource Block Sets". Since it 
had been so long since the encoding for these was finalized (IETF 72, 
July 2008, Dublin and IETF 74, March 2009 San Francisco)  and the 
content of the aforementioned presentation did not correspond in any way 
to the draft-peloso-ccamp-wson-ospf-oeo-02 that it was purported to 
address we had no time to prepare a response.
Fortunately the answer to the issues raised are already contained in 
documents (3) and (4) along with examples of their efficiency.

The "Link Set Field" (section 2.1 of the General Constraint Encoding 
Draft) and the "RB Set Field" (section 3 of the RWA WSON Encode draft), 
are  both based on the highly efficient label set encoding mechanism 
used in RFC3471. Both the "Link Set Field" and "RB Set Field" support 
both "list" and "range" mechanisms. The range mechanism is extremely 
valuable for very compact encoding of large sets of fields. This is 
achieved in the case of link sets by utilizing appropriately assigned 
local link identifiers.  A link set for a large range of links is 
specified by just three 32 bit words (12 octets). This was illustrated 
in the general encoding examples A.1 and A.3 where an 84 port ROADM was 
modeled with only thirty 32-bit words (120 octets). The most common case 
of "link set reuse" is when there is bidirectional symmetry.  Section 
A.4 shows how bidirectional symmetry can be taken into account to reduce 
this to only fifteen 32-bit words (60 octets).

For the resource block set field we have 16 bit resource identifiers and 
a range mechanism. With the range mechanisms a resource set is specified 
with only two 32 bit words (8 octets).  Hence further optimization is 
neither necessary or really possible since TLV, sub-TLV, or "fields" all 
require some level of overhead (i.e., the first 32 bits of the resource 
block set field are overhead).

Due to the efficient encoding of both the "Link Set Field" and "RB Set 
Field" there is very little efficiency to be gained from combining the 
connectivity matrix sub-TLV with the sub-TLVs for the resource block 
connectivity into a "mixed set" as mentioned in the presentation 
following ours in Prague.  We estimate less that 10-20 bytes might be 
saved for a large and complex optical system.

With these final issue resolved, we ask the WG chairs to begin WG last 
call for documents (1)-(4).

Sincerely
Dr. Greg Bernstein

-- 
===================================================
Dr Greg Bernstein, Grotto Networking (510) 573-2237

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From: Lou Berger <[email-masked]>
Date: Mon, 04 Apr 2011 17:28:05 -0400

Greg,

	As you know, in our Prague meeting there was clear consensus
among those in the room to give Pierre (and the others he is working
with) time to formalize their proposed alternate encoding of WSON
supporting information.  There was no consensus to accept their
alternate encodings, merely that what he presented to the WG was
interesting enough that many wanted to see the details.

Once the WG has an opportunity to review the details of the alternate
encoding, the WG can then decide how to proceed.  The details you
have in your mail, as well as your future responses to the proposal,
will be invaluable in helping the WG assess the different encodings
and reaching consensus on a way forward.

We asked Pierre to ensure that his proposal is discussed on the list
in time for adequate review *prior* to the Quebec (next) IETF.  If no
details are forthcoming, then this too gives the WG a clear path
forward.

We appreciate your ongoing stewardship of the WG documents and look
forward to the completion of this work.

Lou and Deborah

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From: Greg Bernstein <[email-masked]>
Date: Tue, 05 Apr 2011 08:15:38 -0700

Hi Lou and Deborah, I guess we just wait now.  Is there anyway for us to 
handle this on the list?
Travel to IETF meetings is expensive in terms of time, greenhouse gas 
emissions, energy, and $.

Dr. Greg Bernstein

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From: Lou Berger <[email-masked]>
Date: Tue, 05 Apr 2011 11:58:21 -0400

We absolutely should have the discussion on the list and see if we can
reach consensus prior to the next meeting.  We can also accommodate
remote presentation as some groups often do.

Lou