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

["Tirumaleswar Reddy (tireddy)" <[e-mail]>]

> -----Original Message-----
> From: [e-mail]
> [mailto:[e-mail]]
> Sent: Friday, September 19, 2014 2:49 PM
> To: Tirumaleswar Reddy (tireddy); [e-mail]; [e-mail]
> Subject: RE: I-D Action: draft-vinapamula-flow-ha-03.txt
> 
> 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.

I thought servers already have such complexity, for example Mobile Networks already use techniques like ARP (Allocation and Retention priority) to accommodate high-priority flow by penalizing low-priority flows.

> 
> >
> >>
> >> >>
> >> >> 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.

Works for me.

-Tiru