Re: [CCAMP] IETF 89 Draft Agenda Posted

["Zafar Ali (zali)" <[e-mail]>]

Hi John- 

Please see in-line.

Thanks

Regards Š Zafar


-----Original Message-----
From: "[e-mail]" <[e-mail]>
Date: Tuesday, February 25, 2014 7:14 AM
To: Fatai Zhang <[e-mail]>, Daniele Ceccarelli
<[e-mail]>, Gert Grammel <[e-mail]>,
"[e-mail]" <[e-mail]>, "[e-mail]" <[e-mail]>
Cc: Alia Atlas <[e-mail]>
Subject: Re: [CCAMP] IETF 89 Draft Agenda Posted

>Fatai,
>
>Comments inline.
>
>Yours Irrespectively,
>
>John
>
>> -----Original Message-----
>> From: Fatai Zhang [mailto:[e-mail]]
>> Sent: Tuesday, February 25, 2014 2:16 AM
>> To: Daniele Ceccarelli; Gert Grammel; John E Drake; Lou Berger; CCAMP
>> Cc: Alia Atlas
>> Subject: RE: [CCAMP] IETF 89 Draft Agenda Posted
>> 
>> Hi all,
>> 
>> I think the network planning (including N node disjoint paths computed
>> concurrently) is very important (we all agree),
>
>[JD]  Concurrent disjoint path computation is not a network planning
>function.  Rather, it is a real-time service offered by the provider
>network   
>
>> but it is also very important and
>> valuable to find disjoint paths sequentially. e.g, a path without
>>protection
>> needs to be upgraded to 1:1 or 1+1 protection, in this case, it needs
>>to exclude
>> the existing path during path setup process. Another example from
>>Zafar, a
>> new service maybe needs to be disjoint from an existing one based on the
>> management purpose.
>
>[JD]  This is the point I made yesterday.  We have a multiplicity of
>solutions but we don't have an agreed upon set of diversity uses cases.

Daniele, et al can keep me honest here.


draft-ceccadedios-ccamp-overlay-use-cases has a section on it. There is
also some text which was not incorporated due to deadline pressure. Plan
is to have draft-ceccadedios-ccamp-overlay-use-cases-05 published in IETF
week. 

>In your example, I could see requesting disjoint paths initially but
>establishing them sequentially, separated by an arbitrary time interval.

Only if SP know that diversity is required at the time service(s) is(are)
created. E.g., when service X was created at time t0, it was not known
that a service Y will be deployed at time t1, requiring the diversity.
Same for upgrade of unprotected service to protected service use case
Fatai mentioned. 

Even when all diversity requirements are known at t0, where do you propose
to run the concurrent Path computation? Please take your favorite example
of remote dual homed UNI (Fig. 5 in
draft-ceccadedios-ccamp-overlay-use-cases).

><snip>