Very good points and clarifications. :-) Regarding "are border nodes allowed", I think if inter-domain communication is required, the border node should allow, shouldn't it?
Also I am wondering whether this requirement is only applied to H-PCE case? H-PCE could be a typical use case. However I believe SVEC tuple is also applied to other use cases Otherwise why RFC5440 specify it In more generic way. Regards! -Qin From: Ramon Casellas [mailto:[email protected]] Sent: Friday, September 13, 2013 3:49 PM To: Qin Wu Cc: [email protected] Subject: Re: [Pce] A comment regarding domain diversity in draft-ietf-pce-hierarchy-extensions Qin, Please see in-line tagged with Ramon> El 13/09/2013 9:22, Qin Wu escribió: Sounds reasonable, I am wondering whether it is sufficient for just defining one new 'D' flag in the SVEC object? Why 'D' flag was not defined when RFC5440 was documented. How do I know computed paths don't have any transit domains in common. Ramon> there are several things to consider: *) the D flag is generic, attached to the SVEC tuple, only to convey a group request constraint. This applies regardless of the actual method used in computation. We should discuss what are the implications, such as "are border nodes allowed (corner case)? Of course, a PCC can also play with inclusion and exclusion provided it has the information on the interconnection of domains, but I don't see this as a common case. *) I understood the requirement was scoped to the H-PCE case, where it is the responsibility of the p-pce to ensure that they are domain-disjoint when selecting the domain sequence for both paths, and before segment expansion. How the parent does this I would say it is is implementation specific (k-shortest disjoint paths, iterative, etc.) *) I would say that, without more information, a PCE or PCC cannot simply deduce whether two paths don't have any transit domains in common, unless this information is conveyed in the path ERO or attributes. I was thinking that the use of domain objects could be used http://tools.ietf.org/html/draft-ietf-pce-pcep-domain-sequence-03 if the EROs are "tagged" with domain information, it can be deduced whether both EROs are disjoint or not Domain diversity is more complicated when computed paths don't even share ingress domain and egress domain. Ramon> I guess we agree :o) Thanks R.
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