Re: [mpls-tp] Proposed liaison to ITU-T on G.8110

["BUSI, ITALO (ITALO)" <[e-mail]>]

Nurit,

thanks for your reply. See in line marked with [ib]

Italo

________________________________
From: Sprecher, Nurit (NSN - IL/Hod HaSharon) [mailto:[e-mail]]
Sent: martedì 29 giugno 2010 12.51
To: BUSI, ITALO (ITALO); [e-mail]; [e-mail]
Cc: [e-mail]
Subject: RE: [mpls-tp] Proposed liaison to ITU-T on G.8110


Hi Italo,

Please see inline.

Best regards,

Nurit



-----Original Message-----
From: ext BUSI, ITALO (ITALO) [mailto:[e-mail]]
Sent: Tuesday, June 29, 2010 1:34 PM
To: Sprecher, Nurit (NSN - IL/Hod HaSharon); [e-mail]; [e-mail]
Cc: [e-mail]
Subject: RE: [mpls-tp] Proposed liaison to ITU-T on G.8110



Nurit,



I have already raised some specific questions for clarification about your last point.



What has been changed in MPLS TTL processing in the last 5 years?



<Nurit> This was a general comment, not specific related to TTL. \<Nurit>



Why do you think TTL processing in MPLS-TP is different from TTL processing in MPLS? What are actually these differences?



<Nurit> I do not think I have said it. \<Nurit>



[ib] The TTL processing in MPLS-TP is either identical to the TTL processing in MPLS or it is different.

If it is identical, G.8110.1 should model it exactly in the same way as G.8110.

A request to define a different model in G.8110.1 means to me that the TTL processing in MPLS-TP is different than in MPLS.

Am I missing something?



I recall I raised a specific question during the last Q12/15 meeting to check whether the TTL processing in MPLS-TP is the same as in MPLS. All those present at that meeting (including ISOC representatives) agreed that the TTL processing is the same.

If this answer that I got at the meeting is incorrect, I would appreciate to understand why.



I do not buy the argument that G.8110 is five years old. RFC 3031 is nine years old but this is not precluding us to make normative reference to it.

<Nurit> Sure, but a lot of work has been done since then on MPLS architecture as documented in other documents. Is it the same in the ITU-T? do we have additional documents on MPLS architecture? \<Nurit>



[ib] As said below, the ITU-T model for all the extensions to MPLS architecture defined by IETF after the approval G.8110 and relevent to MPLS-TP has been described in G.8110.1. G.8110.1 refers to G.8110 for the aspects that are were defined by MPLS at that time and still applicable to MPLS-TP (e.g., TTL processing).



During the development of G.8110.1 a lot of care has been taken by the editor and technical contributors to reuse the functional model of G.8110 when appropriate and to develop extensions to this model where needed.

<Nurit> I am sure. Still we have the concern on the modeling of TTL as a CI. Please refer to my main points in the mail. AM I wrong? \<Nurit>



[ib] G.8110.1 models the TTL processing in exactly the same way as G.8110. If the TTL processing in the same between MPLS-TP and MPLS, I think this is the right way to do. If this is not the case, I would like to understand what are the differences.



I would appreciate if you can point to a specific technical item that has not been properly captured in this work.



Italo





________________________________



      From: Sprecher, Nurit (NSN - IL/Hod HaSharon) [mailto:[e-mail]]

      Sent: martedì 29 giugno 2010 12.09

      To: [e-mail]; BUSI, ITALO (ITALO); [e-mail]

      Cc: [e-mail]

      Subject: RE: [mpls-tp] Proposed liaison to ITU-T on G.8110







      Hi,



      It is correct that the CI is transferred on a "network connection" which is formed by a series of contiguous "link connections" and/or "subnetwork connections" between "termination connection points". We should fix the proposed liaison accordingly!



      Still the concern is valid.



      G.805 refers to the generation (at the source), transport and termination (at the sink) of CI (in the context of a layer network), and also to the interworking of CI of one layer network with the CI another layer, but not to the processing of the CI at each transport entity or port along the network connection.



      Therefore I support the liaison with the correction of TCPs and not APs.



      I think also that the fact that G.8110 (which is used as a normative reference) has not been updated since 2005, raises more concerns. MPLS was worked out since 2005 and there is a need to understand the gaps and check consistencies, etc.



      Best regards,



      Nurit







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