Diverse path failure and optimality in draft-dachille-inter-area-path-protection

[ugo monaco <monaco@infocom.uniroma1.it>]

Dear ccamper, Zafar, Dimitri,

as anticipated in the recent email by Vishal we are addressing 
several important comments collected at Seoul regarding the joint-selection 
of diverse paths with ARO, i.e. the approach proposed in 
<http://www.ietf.org/internet-drafts/draft-dachille-inter-area-path-protection-00.txt>.

As Vishal did I summarized your comments to ensure that we rightly
understood inputs, and to help people on the ML follow
and contribute to the discussion.
Comments from others who have feedback are welcome, and
much appreciated.

Please let me know if you had any additional comments
as well. We will take these into account in providing our
responses, and, later, in updating the document.



Thanks again for your feedback on our draft during the Seoul meeting.
Best Regards.

Ugo Monaco


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Zafar's questions:

i) What happens when the setup of the diverse path fails, or there is a
failure on it after it has been set up?

ii) Relationship of this scheme to PCS/PCE approach of JP?


Dimitri Papadimitriou

i) Your question was about why we are trying for optimality with a joint 
path selection scheme, when it is not possible, especially as the number 
of AS's or areas along a path increase, to achieve the *global* optimum.
Your other comment was that we should mention this somewhere in the document.

Please note that in response to this last question Fabio Ricciato listed many
advantages of a joint computation (with ARO) of inter-area/AS paths in a 
prevoius email posted on the ML "About optimality of inter-AS parallel 
computation in draft-dachille-inter-area-path-protection".
We hope that Fabio rightly addressed your input and we will appreciate further 
comments and notes.