Subject: [Diffserv-interest] Re: [Diffserv] Behaviour of different flows in Diffserv network

From: Brian E Carpenter <[email-masked]>
Date: Fri, 07 Sep 2001 16:44:21 -0500

Christophe Gouault wrote:
> 
> [email-masked] wrote:
> 
> > Hi All,
> > I have this question regarding a situation when the different flows are
> > aggregated at the Diffserv network edge with similar constraints. They get
> > allocated a particular DSCP to receice a treatment through the diffserv
> > network. What would happen lets say that there is a mixture of TCP and UDP
> > flows in that aggregate and they hit congestion. What effect would it have
> > on those indivdual flows though part of an aggregate but under congestion
> > situation TCP and UDP flow behave differently.
> >
> > Regards
> > Asim
> > Vodafone
> >
> > _______________________________________________
> > diffserv mailing list
> > [email-masked]
> > https://www1.ietf.org/mailman/listinfo/diffserv
> > Archive: http://www2.ietf.org/mail-archive/working-groups/diffserv/current/maillist.html
> 
> Hi Asim,
> 
> IMHO, since TCP and UDP behave differently in congestion situations, they shouldn't be
> aggregated in the same class of service. Only flows with similar constraints should be
> aggregated.
> 
> Christophe.

That may be correct in theory, but in practice I am sure the situation Asim decribes
will arise (for example if all of one customer's traffic gets the same SLA). What happens
is exactly what happens today: you have effectively created a private Internet with
TCP and non-TCP traffic competing. TCP will slow down and UDP will lose data.

[switched this to the diffserv-interest list]

  Brian

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