Re: [CCAMP] Requirement for singled ended provisioning of associated bidirectional LSPs

[Attila Takacs <[e-mail]>]

Hi all, 
Please see inline [at].


-----Original Message-----
From: Lou Berger [mailto:[e-mail]] 
Sent: Friday, April 15, 2011 3:50 PM
To: Attila Takacs
Cc: [e-mail]
Subject: Requirement for singled ended provisioning of associated bidirectional LSPs

[Subject: Was Re: [CCAMP] poll on making
draft-zhang-mpls-tp-rsvpte-ext-associated-lsp-04 a WG document]

> 2) Point related to the contents of the draft.
>
> As this is a technical point, and independent of the poll.  I'll start 
> a new thread on this in a separate mail.
>

As I (as WG member, not chair) understand it, you are questioning the requirement for the "single sided mode".  I think this is a good question.  As you pointed out, I believe I suggest that this question be raised, by the authors, on the TP list.

[at] Fei, is/was there any conclusion on the TP list?


RFC5645 seems to allow for independent provisioning of associated, but it doesn't preclude the "single sided mode".  It also has requirements
11 and 12 which are certainly facilitated by "single sided mode".

[at] I think requirements 11 and 12 can be fulfilled by using an association id on both LSPs with "double-sided mode" at LSP establishment or at a later point for association. 

In the case LSPs should be associated later on, after establishment, a simple "single sided" solution might be used to allow single-touch association, this is mainly an optimization not a required feature I guess. In this case besides the association id one may also send the LSP id of the reverse direction to which the association should be established, which in turn would result in the resignalling of that LSP with the association id. Doing more elaborate "single-sided" signaling, e.g, including reverse bw and qos parameters seems to me to add unnecessary complexity. 

Best regards,
Attila





I believe you also raise some valid issues with the current definition of the processing rules. I'll defer my comments on this for now.

Lou

BTW This isn't the first time that "single sided mode" has been suggest.
I seem to remember discussing a proposal on this from Juha Heinanen at the Adelaide IETF.  I also know of one vendor-specific implementation that never made it to the field or the WG.

On 4/15/2011 9:42 AM, Lou Berger wrote:
> Attila,
> 	So we have two points here:
> 1) WG procedure related
> 
> So this mail is in response to a poll. As your answer is (a).  I (as
> chair) know how to interpret you position, i.e., "Yes/Support".
> 
> 2) Point related to the contents of the draft.
> 
> As this is a technical point, and independent of the poll.  I'll start 
> a new thread on this in a separate mail.
> 
> Thanks,
> Lou
> 
> On 4/14/2011 1:06 PM, Attila Takacs wrote:
>> Hi Lou, all,
>> It would be nice to clarify the scope of the proposed extension. 
>> I would say (a) if that does not include commitment to work on the "single sided mode". To my current understanding that operation mode is not required for associated bidirectional LSPs. There is no discussion in the document about which operation mode is really needed, if I'm not mistaken similar comments were raised in Beijing, but this is not addressed in the document. Hence my confusion.
>> Thanks,
>> Attila
>>   
>>
>> -----Original Message-----
>> From: Lou Berger [mailto:[e-mail]]
>> Sent: Wednesday, April 13, 2011 2:43 PM
>> To: Attila Takacs
>> Cc: [e-mail]
>> Subject: Re: [CCAMP] poll on making 
>> draft-zhang-mpls-tp-rsvpte-ext-associated-lsp-04 a WG document
>>
>> Attila,
>> 	So I appreciate your comment, and would like to have this discussion, but I think I need some clarification from the perspective of the poll.
>>  I'm unsure if you're saying:
>> (a) support this document becoming a WG document and would like
>>     discuss the point raised below in the context of a WG document or
>> (b) do NOT support this document becoming a WG document until the
>>     point you raise becomes a WG document
>>
>> Can you clarify if you mean (a) or (b)?
>>
>> Lou
>>
>> On 4/12/2011 4:27 PM, Attila Takacs wrote:
>>> Hi authors,
>>>
>>> You talk about two provisioning models: "single" and "double" sided modes. 
>>>
>>> Double sided is clear, it uses independent signaling for the two LSPs. 
>>>
>>> Single sided, if I understood correctly, somehow binds the two LSP signaling phases together. I have some doubts that this model is needed. It seems to complicate operation and it also begs the question why not use bidirectional LSPs instead. 
>>>
>>> I think two independently signaled LSPs with the addition of the proposed Association object would do the job addressing the associated bidirectional LSP requirements, so that transit nodes are also aware of the binding.
>>>
>>> Best regards,
>>> Attila
>>>
>>> -----Original Message-----
>>> From: [e-mail] [mailto:[e-mail]] On 
>>> Behalf Of Lou Berger
>>> Sent: Friday, April 01, 2011 11:24 AM
>>> To: [e-mail]
>>> Subject: [CCAMP] poll on making
>>> draft-zhang-mpls-tp-rsvpte-ext-associated-lsp-04 a WG document
>>>
>>> All,
>>>
>>> This is to start a two week poll on making
>>> draft-zhang-mpls-tp-rsvpte-ext-associated-lsp-04 a ccamp working group document. Please send mail to the list indicating "yes/support"
>>> or "no/do not support".  If indicating no, please state your technical reservations with the document.
>>>
>>> The poll ends Friday April 15.
>>>
>>> Much thanks,
>>> Lou (and Deborah)
>>>
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>>>
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>>>
>>
>>
>>
>>