Hi Vijay,
On Tue, Jul 23, 2013 at 9:37 PM, Vijay K. Gurbani <[email protected]> wrote:
> On 07/23/2013 12:39 PM, Y. Richard Yang wrote:
>
>> Hi Vijay,
>>
>> Let me try to summarize your proposed strategy:
>>
>> Syntax
>> =====
>> For the root IRD (the one discovered from the discovery protocol)
>> obtained by a client, if there are *more than one* network map resources
>> listed in the IRD, one and only one of the network maps MUST be marked
>> with a "default" attribute.
>>
>
> Richard: Yes. (Sorry for the delay, email is sporadic due to travel.)
>
>
> Footnotes: (1) in the general case, an IRD may have 0 network maps
>> (e.g., only endpoint properties); (2) consider the deployment cases
>> where the ALTO Service provides multiple "orthogonal" network maps (i.e.
>> harder to argue which one is more "default" than the other, the IRD can
>> choose to mark one as default.
>>
>
> For (1), I suspect you are thinking of datacenter type of
> applications. In such a case, it is obvious perhaps that there will not
> be any cost maps either. So, the semantics could simply be that the
> absence of a network map implies no contract to provide cost maps
> either, and therefore the IRD only contains properties of some kind.
>
> Regarding (2), if the intent is to keep the client simple (one of the
> prerequisites I gathered from the earlier thread), then indicating one
> of these orthogonal maps as default seems reasonable. Either the
> provider can do so or the client can simply pick one map and consider
> it as the default. My preference would be for the service provider
> to mark one as default. After all, the service provider knows (a)
> the network and (b) the identity of the client. Knowing (b), the
> service provider can tailor the network map appropriately (at least
> that is what we have been assuming so far).
>
>
Sounds good.
>
> Q: should we change "more than one" to "at least one" in the preceding?
>> If not, the interpretation is that when only one network map, it has a
>> default attribute automatically marked.
>>
>
> Fine, just so long as we spell this out in the draft.
>
>
OK.
>
> Semantics
>> ========
>> 1. If a client uses only network map as guidance for traffic
>> localization, it should use the default network map, as the default
>> behavior;
>>
>
> Yes.
>
>
> 2. If a client uses both network map and cost map, it should use the
>> "routingcost" cost map based on the default network map, as the default
>> behavior.
>>
>
> Yes.
>
>
> Q: what if there are multiple "routingcost" cost maps based on the same
>> network map? I would say Forbidden.
>>
>
> Yes.
>
> We need to get a protocol out that is reasonably broad enough to cover
> many cases without having to poke at corner cases. My feeling is that
> we are close to this now. If we get overwhelmed by the corner cases,
> we may not get too far too quickly.
>
>
Agree.
Thanks!
Richard
>
> Thanks,
>
> - vijay
> --
> Vijay K. Gurbani, Bell Laboratories, Alcatel-Lucent
> 1960 Lucent Lane, Rm. 9C-533, Naperville, Illinois 60563 (USA)
> Email: vkg@{bell-labs.com,acm.org} /
> vijay.gurbani@alcatel-lucent.**com<[email protected]>
> Web: http://ect.bell-labs.com/who/**vkg/<http://ect.bell-labs.com/who/vkg/> |
> Calendar:
> http://goo.gl/x3Ogq
>
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