Re: [Diffserv-interest] congestion in diffserv network
Brian E Carpenter <brc@zurich.ibm.com> Wed, 29 October 2003 11:10 UTC
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Date: Wed, 29 Oct 2003 12:07:02 +0100
From: Brian E Carpenter <brc@zurich.ibm.com>
Organization: IBM
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To: John Schnizlein <jschnizl@cisco.com>
CC: Feng Y <feng6@uwindsor.ca>, diffserv-interest@ietf.org
Subject: Re: [Diffserv-interest] congestion in diffserv network
References: <4.3.2.7.2.20031028122043.02283790@wells.cisco.com>
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Another way to look at it is that what diffserv does is split the network into several separate networks, but each of them retains the statistical properties of a single Internet. Brian John Schnizlein wrote: > > The simple reason that congestion can occur is that the TCA > need not limit incoming traffic sufficiently to avoid it. > The TCA for expedited forwarding is the only one, of many > traffic classes, that seeks to eliminate potential congestion, > in order to minimize delay and jitter. > > The parameters of other class definitions, assured forwarding > for example, are intended to mark traffic at different ingress > rates for different treatment when congestion occurs. Note > that this anticipates that congestion will occur. > > Please recall that the high link utilization in an IP network > is obtained in large measure because traffic loads are high > enough to produce occasional congestion. Cooperative management > of this congestion is the responsibility of transport-layer > protocols. > > John > > At 10:43 AM 10/28/2003, Feng Y wrote: > >... I wonder why the > >overloading or even congestion occurs in diffserv network. > >In diffserv architecture, the DS ingress node is > >responsible for ensuring that the traffic entering the DS > >domain conforms to any traffic conditioning agreement (TCA) > >between it and the other domain to which the ingress node > >is connected [RFC 2475]. Moreover, Traffic conditioning > >performs metering, shaping, policing and/or re-marking to > >ensure that the traffic entering the DS domain conforms to > >the rules specified in the TCA, in accordance with the > >domain's service provisioning policy. So what causes the > >overloading or congestion in diffserv? Does anyone explain > >it for me or give me some references. Thanks in advance. > > _______________________________________________ > Diffserv-interest mailing list > Diffserv-interest@ietf.org > https://www1.ietf.org/mailman/listinfo/diffserv-interest -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Brian E Carpenter Distinguished Engineer, Internet Standards & Technology, IBM NEW ADDRESS <brc@zurich.ibm.com> PLEASE UPDATE ADDRESS BOOK _______________________________________________ Diffserv-interest mailing list Diffserv-interest@ietf.org https://www1.ietf.org/mailman/listinfo/diffserv-interest
- [Diffserv-interest] congestion in diffserv network Feng Y
- Re: [Diffserv-interest] congestion in diffserv ne… John Schnizlein
- Re: [Diffserv-interest] congestion in diffserv ne… Brian E Carpenter
- [Diffserv-interest] QoS in diffserv network Feng Y
- Re: [Diffserv-interest] QoS in diffserv network Brian E Carpenter
- Re: [Diffserv-interest] QoS in diffserv network Zoltan.Balint
- Re: [Diffserv-interest] QoS in diffserv network Brian E Carpenter