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

Hi Anna

 Please see in line!

> -----Original Message-----
> From: Anna Charny (acharny) [mailto:acharny@cisco.com] 
> Sent: woensdag 19 maart 2008 17:43
> To: Georgios Karagiannis; Steven Blake
> Cc: pcn@ietf.org
> Subject: RE: [PCN] Concensus questions from Thursday's PCN meeting
> 
> Georgios,
>  
> Please see below:
> 
> > -----Original Message-----
> > From: pcn-bounces@ietf.org [mailto:pcn-bounces@ietf.org] On 
> Behalf Of 
> > Georgios Karagiannis
> > Sent: Wednesday, March 19, 2008 11:25 AM
> > To: 'Steven Blake'
> > Cc: pcn@ietf.org
> > Subject: Re: [PCN] Concensus questions from Thursday's PCN meeting
> > 
> > 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.>>
> 
> But these rerouted and previously unmarked packets will be 
> marked on the congested interface, would they not?

Georgios: If they are not passing throug the severely congested node, they
will not be marked!

Best regards,
Georgios

> 
> Anna 
> 
> > 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).
> > 
> > 
> > Best regards,
> > Georgios
> > 
> > 
> > 
> >  
> > 
> > > -----Original Message-----
> > > From: Steven Blake [mailto:steven.blake@ericsson.com]
> > > Sent: woensdag 19 maart 2008 16:17
> > > To: Georgios Karagiannis
> > > Cc: pcn@ietf.org
> > > Subject: Re: [PCN] Concensus questions from Thursday's PCN meeting
> > > 
> > > Georgios,
> > > 
> > > Let me try to paraphrase the scenario you are describing:
> > > 
> > > - 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).
> > > - 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).
> > > 
> > > Does this description accurately capture your scenario?
> > > 
> > > 
> > > Regards,
> > > 
> > > =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
> > > Steven Blake                <steven.blake@ericsson.com>
> > > Ericsson/Redback Networks               +1 919-472-9913
> > > 
> > 
> > 
> > _______________________________________________
> > PCN mailing list
> > PCN@ietf.org
> > https://www.ietf.org/mailman/listinfo/pcn
> > 
> 

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