Hi Ramon,

Thanks for your suggestion. I concur with your clarifying texts to keep the 
consistency between this PCEP extension and the encoding draft. 

Regards,
Young
-----Original Message-----
From: Ramon Casellas [mailto:[email protected]] 
Sent: Thursday, October 27, 2011 4:09 AM
To: Margaria, Cyril (NSN - DE/Munich)
Cc: [email protected]
Subject: Re: Some proposal for the next revision of draft-lee-pce-wson-rwa-ext

Dear co-authors,


While reviewing the current draft, I noticed the following: currently, 
FEC / modulation restrictions are proposed as one TLV per modulation / 
FEC as endpoint restrictions

However, in draft-ietf-ccamp-rwa-wson-encode-12 the actual TLV is a "fec 
list" or a "modulation list"

I believe that having cases where we have a TLV as one element and cases 
where we have TLV as a list is error prone, and in order to unify I 
would like to align draft-lee-pce-wson-rwa-ext to 
draft-ietf-ccamp-rwa-wson-encode-12
especially since the restriction TLVs can appear more than once --> add 
them as a list.

A first proposed new wording would be as follows:

<endpoint-restriction> ::= <LABEL-REQUEST>
<label-restriction-list>
                                          
[<signal-compatibility-restriction>...]
           Where

           signal-compatibility-restriction ::= 
<MODULATION-FORMAT-LIST>|<FEC-LIST>

with e.g.
         Value := A list of FEC type Fields


One issue remains. since draft-lee...rwa-02 only used one FEC element 
field / MODULATION element filed per TLV, it could use the element 
length field as a reserved field and add a flag X to exclude or include

A way to solve this is to allow <signal-compatibility-restriction> to 
appear twice. One for inclusion and one for exclusion., or to define 2 TLVs

<endpoint-restriction> ::= <LABEL-REQUEST>
<label-restriction-list>
                                          
[<signal-compatibility-restriction>...]
           Where

           signal-compatibility-restriction ::= 
<MODULATION-FORMAT-LIST-INCLUDE-TLV> <FEC-LIST-INCLUDE-TLV> 
<MODULATION-FORMAT-LIST-EXCLUDE-TLV> <FEC-LIST-EXCLUDE-TLV>

My main argument for this is to align fully with 
draft-ietf-ccamp-rwa-wson-encode-12


Finally, I would like to consider the use case where the LSC LSP crosses 
an O/E/O. Do we need control on the modulation/FEC at that point?

Comments?

R.



-- 
Ramon Casellas, Ph.D.
Research Associate - Optical Networking Area -- http://wikiona.cttc.es
CTTC - Centre Tecnològic de Telecomunicacions de Catalunya, PMT Ed B4
Av. Carl Friedrich Gauss, 7 - 08860 Castelldefels (Barcelona) - Spain
Tel.: +34 93 645 29 00 -- Fax. +34 93 645 29 01

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