On Mon, May 14, 2012 at 2:24 AM, Songhaibin <[email protected]> wrote: > Hi Rich, > > > >> -----Original Message----- >> From: [email protected] [mailto:[email protected]] On Behalf Of >> Richard Alimi >> Sent: Sunday, May 13, 2012 2:05 PM >> To: Songhaibin >> Cc: Enrico Marocco; [email protected] >> Subject: Re: [alto] WGLC: draft-ietf-alto-protocol-11 >> >> On Mon, Apr 23, 2012 at 6:47 PM, Songhaibin <[email protected]> wrote: >> > In general, this draft is in good shape. >> > >> > One randomly caught problem, in Section 5.1.2.2, the ordinal mode >> introduction, it says this cost mode is a ranking from a particular source >> to a set of >> destinations. But in Section 5.2, the introduction of cost map structure, >> the cost >> mode "ordinal" can be applied to m*n entries in the cost map. So I suggest to >> modify the previous section 5.1.2.2 to make them consistent. >> > >> >> Thanks for catching that. In fact, the sentence "If the Cost Mode is >> 'ordinal', the Path Cost of each communicating pair is relative to the >> m*n entries" can probably just be removed. >> > > I'm sorry that I have a different opinion here.
No need to apologize :) > The "ordinal" cost to entries in a matrix makes sense to me. I prefer to > modify the definition in 5.1.2.2, the ranking can be from multiple sources to > multiple destinations. Or is there special reason to limit it to 1*n? > As an author/editor, I will say that the intent was for them to be relative to only the costs from the same source. However, if the WG believes that should not be he case, then please do say so. To summarize the differences in semantics: (a) The interpretation that an ordinal cost is relative to all other entries in the cost map means a server could convey a policy like "I would rather you send traffic from s1 -> d1 instead of from s2 -> d2" (b) The interpretation that an ordinal cost is relative only to other ordinal costs from that same source means you can't specify that policy in an ordinal map. The original thought was that (b) makes the protocol a bit simpler to reason about and captures the major use cases for ordinal costs. However, it has slightly less expressive power when it comes to encoding policies. It is certainly worth having the discussion as to which way we should go. Any other comments? For completeness, note that we did have a discussion with regards to whether costs had to be unique, and the decision was "no": http://www.ietf.org/mail-archive/web/alto/current/msg01064.html (your question is different from that, though.) Thanks, Rich > BR, > -Haibin > >> Thanks, >> Rich >> >> > BR, >> > -Haibin >> > >> >> -----Original Message----- >> >> From: [email protected] [mailto:[email protected]] On Behalf Of >> Enrico >> >> Marocco >> >> Sent: Monday, April 16, 2012 5:20 PM >> >> To: [email protected] >> >> Subject: [alto] WGLC: draft-ietf-alto-protocol-11 >> >> >> >> >> >> The chairs would like to declare a Working Group Last Call for >> >> draft-ietf-alto-protocol-11, ending Friday May 11th. >> >> >> >> Please do review the latest version of the draft, and send any comments to >> the >> >> list before the expiry of WGLC so we can get this document ready for the >> IESG. >> >> >> >> -- >> >> Ciao, >> >> Enrico >> > >> > _______________________________________________ >> > alto mailing list >> > [email protected] >> > https://www.ietf.org/mailman/listinfo/alto _______________________________________________ alto mailing list [email protected] https://www.ietf.org/mailman/listinfo/alto
