Re: [PCN] Concensus questions from Thursday's PCN meeting

["Georgios Karagiannis" <[e-mail]>]

Hi Phil

But in order to trigger the admission control and flow termination, 
the situation CLE > 1% has to be first triggered.

Best regards,
Georgios
 

> -----Original Message-----
> From: [e-mail] [mailto:[e-mail]] 
> Sent: woensdag 19 maart 2008 17:07
> To: [e-mail]; [e-mail]
> Cc: [e-mail]
> Subject: RE: [PCN] Concensus questions from Thursday's PCN meeting
> 
> Georgios,
> 
> I notice you refer to CLE below. Note that for termination 
> the relevant parameter is the Sustainable rate, that is the 
> rate of unmarked pkts (or, if SM being used, this rate is 
> multiplied by the domain-wide parameter U). 
> 
> phil
> 
> > -----Original Message-----
> > From: [e-mail] [mailto:[e-mail]] On 
> Behalf Of 
> > Georgios Karagiannis
> > Sent: 19 March 2008 15:49
> > To: 'Steven Blake'
> > Cc: [e-mail]
> > Subject: Re: [PCN] Concensus questions from Thursday's PCN meeting
> > 
> > Hi Steven
> > 
> > Okay, I will have to spend some time on this!
> > 
> > Best regards,
> > Georgios
> > 
> > 
> > > -----Original Message-----
> > > From: Steven Blake [mailto:[e-mail]]
> > > Sent: woensdag 19 maart 2008 16:43
> > > To: Georgios Karagiannis
> > > Cc: [e-mail]
> > > Subject: RE: [PCN] Concensus questions from Thursday's PCN meeting
> > >
> > > On Wed, 2008-03-19 at 16:24 +0100, Georgios Karagiannis wrote:
> > >
> > > > Hi Steven
> > > >
> > > > Please see that I have included some information into the
> > > last bullet:
> > > >
> > > > - There is an ingress-egress aggregate whose traffic is
> > > split across
> > > > multiple paths via ECMP.
> > > >  - Traffic is admitted along this split path.
> > > >  - One (or more) of the paths fails.
> > > >  - One (or more) of the remaining paths becomes severely
> > > congested (for
> > > >    example because there is traffic from other ingress-egress 
> > > > aggregates flowing along that path).
> > > > - <<Due to the ECMP routing not congested paths will
> > > forward packets
> > > > belonging to
> > > >   the same ingress-egress-aggregate that will be unmarked.>>
> Marked
> > > > packets are
> > > >   preferentially dropped at the severely congested
> > > >   router(s). As a consequence, not enough marked traffic arrives
> at
> > > > the egress router to drive the CLE for the ingress-egress
> aggregate
> > > > above the threshold needed to trigger a response (termination,
> say).
> > >
> > > Ok.  To be specific, the egressrouter  will see some fraction of 
> > > packets from the severely congested router(s), some of 
> which will be 
> > > marked, and will see a larger fraction of un-marked 
> packets from the 
> > > un-pre-congested routers.
> > >
> > > So let me now ask you this: given N ECMP paths (after a path 
> > > failure), with one being severely congested and the rest being 
> > > un-pre-congested, and given a CLE threshold CLE_thresh at 
> the egress 
> > > router, can you solve for the minimum PCN_lower_threshold 
> value at 
> > > the severely congested router, where PCN still works (e.g., CLE 
> > > crosses the threshold), for the two cases where (1) 
> marked packets 
> > > are preferentially dropped, and (2) marked packets are 
> dropped with 
> > > equal probability with un-marked packets?
> > >
> > >
> > >
> > > Regards,
> > >
> > > =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
> > > Steven Blake                <[e-mail]>
> > > Ericsson/Redback Networks               [phone]
> > >
> > 
> > 
> > _______________________________________________
> > PCN mailing list
> > [e-mail]
> > https://www.ietf.org/mailman/listinfo/pcn
> 


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