Subject: Re: [alto] Graph representation format deliverable as WG item

From: "Randriamasy, Sabine (Nokia - FR)" <[email-masked]>
Date: Fri, 18 Nov 2016 17:45:15 +0000

Hello authors of path vector and RSADE extensions and all,

Both drafts address several emerging use cases, in particular, the multi-path 1st hop, where each hop corresponds to a different choice of access technology. 

I'd like to resume the discussion started in IETF96-Berlin upon Richard's presentation, see https://www.ietf.org/proceedings/96/slides/slides-96-alto-6.pdf    

- issue 2 slide 12: multiple (S,D) pairs (with S and D = sets) in a query is more than useful. 
Is there a way to allow this as well for "regular" ECS and F/CM ? Can we apply this to both "flows/endpoints" and "PID-paths" ? 

- issue 2 design choices: a smooth transition would be using native cost maps with multiple input several (S,D) pairs.   

- Cost metric and mode for "ane-aware paths":  
Slide 17 illustrates for a (S,D) pair: metric = "ane", mode = "path-vector" = array of N >= 1 "ane"
Other modes could be:  
- mode = "path-graph", (multiple path-vectors - for RSADE or multi-choice paths)
- mode = "path-e2e" (single switch N=0 base ALTO mode usually not used),

- conveying ane costs and properties (slides 15, 16, 17) on multi-hop maps: 
In any case, ane property/cost services need to be specified and indicated in the IRD so that the client understands what "ne24" points to. So I suggest the anep-map to be systemetically referenced in the dependent-vtags. As for nep-map values:
- inline: information is self-contained and saves round trips but response may be heavy
- reference: ALTO Client gets anep map separately if needed. 

How about letting a Server decide what option to propose? 
A Server may even directly integrate the cost values in a multi-cost response, provided it has specified a anep-map and references it in its response.     

If for instance a client requests  metric "BW" in "path-vector" mode, the protocol may request that it also requests metric "ane" in this mode (same for "path-graph" mode). 

Does this make sense ?
 
Thanks,
Sabine

>>-----Original Message-----
>>From: alto [mailto:[email-masked]] On Behalf Of Vijay K. Gurbani
>>Sent: mercredi 31 août 2016 23:08
>>To: Y. Richard Yang <[email-masked]>
>>Cc: [email-masked]; draft-gao-alto-routing-state-
>>[email-masked]; IETF ALTO <[email-masked]>
>>Subject: Re: [alto] Graph representation format deliverable as WG item
>>
>>On 08/31/2016 03:54 PM, Y. Richard Yang wrote:
>>> Hi Vijay, all,
>>>
>>> Thanks a lot for the reminder. This is a keep-alive that the authors
>>> are doing the work and will post an outline to clarify to the WG on
>>> the path soon.
>>
>>Richard: Awesome!  Thanks.
>>
>>- vijay
>>--
>>Vijay K. Gurbani, Bell Laboratories, Nokia Networks
>>1960 Lucent Lane, Rm. 9C-533, Naperville, Illinois 60563 (USA)
>>Email: [email-masked] / [email-masked]
>>Web: http://ect.bell-labs.com/who/vkg/  | Calendar: http://goo.gl/x3Ogq
>>
>>_______________________________________________
>>alto mailing list
>>[email-masked]
>>https://www.ietf.org/mailman/listinfo/alto