Re: [pcp] I-D Action: draft-vinapamula-flow-ha-03.txt

[<[e-mail]>]

Re-,

Please see inline.

Cheers,
Med

>-----Message d'origine-----
>De : Tirumaleswar Reddy (tireddy) [mailto:[e-mail]]
>Envoyé : vendredi 19 septembre 2014 11:07
>À : BOUCADAIR Mohamed IMT/OLN; [e-mail]; [e-mail]
>Objet : RE: I-D Action: draft-vinapamula-flow-ha-03.txt
>
>> -----Original Message-----
>> From: [e-mail]
>> [mailto:[e-mail]]
>> Sent: Friday, September 19, 2014 11:38 AM
>> To: Tirumaleswar Reddy (tireddy); [e-mail]; [e-mail]
>> Subject: RE: I-D Action: draft-vinapamula-flow-ha-03.txt
>>
>> Hi Tiru,
>>
>> Please see inline.
>>
>> Cheers,
>> Med
>>
>> >-----Message d'origine-----
>> >De : Tirumaleswar Reddy (tireddy) [mailto:[e-mail]] Envoyé :
>> >jeudi 18 septembre 2014 17:18 À : BOUCADAIR Mohamed IMT/OLN;
>> >[e-mail]; [e-mail] Objet : RE: I-D Action:
>> >draft-vinapamula-flow-ha-03.txt
>> >
>> >
>> >I can think of two to three ways to address this problem 1)Applications
>> >with required authorization can only signal that it's a high priority
>> >flow.
>> >2)End User with the help of a web-portal let's say provided by Home
>> >Gateway or ISP can re-arrange priorities of flows. Applications like
>> >uTorrent already provide UI so that user can assign priorities for
>> >different file downloads.
>> >3)Just like various good background applications use LEDBAT to limit
>> >congestion, we can except that such applications in future will
>> >explicitly signal that it's a low priority flow.
>> >
>>
>> [Med] Do you mean PCP messages will be modified in path?
>
>No, I meant there will be some applications that will declare that they
>have low-priority flows just like applications that declare  that HA is not
>required.

[Med] OK. If we assume a priority level was added, what will be the behavior of the server when it receives a request for high-priority flow but there is no resources to honor the request? Should it remove entries with low-priority from the check-pointing table? I'm afraid this will induce more complexity at the server side. 

>
>>
>> >>
>> >> Wouldn't (1) be sufficient to address the case you mentioned in your
>> >> message?
>> >
>> >I don't think it is sufficient, it does not provide relative priority.
>>
>> [Med] Do these flows require check-pointing too? Or you only care about
>> prioritizing these flows during congestion events?
>
>These flows could care about both check-pointing and prioritization or care
>about only one of them.

[Med] I can understand the priority level for flows that are subject to check-pointing, but I have an issue to generalize this draft to address the prioritization purpose ** only **. The problems are not the same. If prioritization is needed as a requirement in its own (which I understand since I'm for a mean to indicate at least DSCP), then a dedicated option can be defined for that purpose.