From: Dmitry Volkov (dmitry.volkov@rogers.com)
Date: Fri Jun 11 2004 - 11:10:35 GMT-3
Yeah, Ok. Thanks for reference.W.Odom page 456
FRED (flow based WRED) overcomes the problem of TCP starvation.When
nonadaptive flows (UDP) compete with adaptive flows (TCP), WRED discards
packets from all the flows. However, only the TCP flows adapt, sending less
traffic into the network, but UDP flows do not slow down. Queues can become
filled with packets from large-volume UDP flows, causing the TCP flows to
get progressively less queue space. This phenomenon is called TCP
starvation.
Both WRED and FRED discard packets before tail drop is required, hoping to
get the senders of the traffic to slow down, thereby reducing congestuion.
FRED, however, adds the goal of stopping TCP starvation by watching for
hungry UDP flows that try to use too much of a queue. FRED aggressively
discards these hungry UDP flows, termed nonadaptive flows, preventing these
flows from consuming to much a queue.
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On
> Behalf Of Alexander Arsenyev (GU/ETL)
> Sent: Friday, June 11, 2004 7:58 AM
> To: 'Volkov, Dmitry'; ccielab@groupstudy.com
> Subject: RE: Custom Queue - correction
>
>
> Hello,
> Please have a look
> http://www.cisco.com/univercd/cc/td/doc/product/software/ios12
> 2/122cgcr/fqos_c/fqcprt3/qcfconav.htm#1001041
> Alternatively, Cisco DQOS book will provide excellent info on FRED.
> HTH,
> Cheers
> Alex
>
> -----Original Message-----
> From: Volkov, Dmitry [mailto:Dmitry.Volkov@allstream.com]
> Sent: 11 June 2004 12:47
> To: Alexander Arsenyev (GU/ETL); ccielab@groupstudy.com
> Subject: RE: Custom Queue - correction
>
>
> What is FRED ? Flow based WRED ? How does it "better" than
> WRED for UDP traffic
> Thanks,
> Dmitry
>
> > -----Original Message-----
> > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On
> > Behalf Of Alexander Arsenyev (GU/ETL)
> > Sent: Friday, June 11, 2004 7:23 AM
> > To: 'ccielab@groupstudy.com'
> > Subject: RE: Custom Queue - correction
> >
> >
> > I see a sentence is missing in my previous post, below is a
> > corrected one:
> >
> > The traffic is rarely unidirectional (multicast is one
> > exception) so I believe either
> > a) enabling Custom Queueing for one interface and WRED/FRED
> > on other interfaces (for return traffic)
> > b) enabling custom queueing on egress interface and enabling
> > WRED (or FRED for UDP, depending on traffic profile) on
> > ingress interface(s)
> > would suit the requirement.
> >
> > HTH,
> > Cheers
> > Alex
> >
> > -----Original Message-----
> > From: nobody@groupstudy.com
> [mailto:nobody@groupstudy.com]On Behalf Of
> > Alexander Arsenyev (GU/ETL)
> > Sent: 11 June 2004 09:56
> > To: 'ccielab@groupstudy.com'
> > Subject: RE: Custom Queue
> >
> >
> > Hello
> >
> > The traffic is rarely unidirectional (multicast is one
> > exception) so I believe enabling custom queueing on egress
> > interface and enabling WRED (or FRED for UDP, depending on
> > traffic profile) on ingress interface(s) would suit the requirement.
> >
> > HTH,
> > Cheers
> > Alex
> >
> > -----Original Message-----
> > From: nobody@groupstudy.com
> [mailto:nobody@groupstudy.com]On Behalf Of
> > Dan
> > Sent: 11 June 2004 05:53
> > To: Richard Dumoulin
> > Cc: Peng Zheng; Carlos G Mendioroz; ccielab@groupstudy.com
> > Subject: Re: Custom Queue
> >
> >
> > But red is not part of custom queue
> >
> >
> > Richard Dumoulin wrote:
> >
> > > Sounds like configuring RED such that it aggressively
> drops packets,
> > >
> > > --RIchard
> > >
> > > -----Original Message-----
> > > From: Dan [mailto:dans@danbsd.a.la]
> > > Sent: jueves, 10 de junio de 2004 22:42
> > > To: Peng Zheng
> > > Cc: Carlos G Mendioroz; ccielab@groupstudy.com
> > > Subject: Re: Custom Queue
> > >
> > >
> > > The doc says that queue 0 is unlimited.
> > >
> > >
> > >
> > > Peng Zheng wrote:
> > >
> > > >Is a queue size 0 reasonable?
> > > >
> > > >--- Carlos G Mendioroz <tron@huapi.ba.ar> wrote:
> > > >
> > > >
> > > >>Have a small queue ?
> > > >>
> > > >>Peng Zheng wrote:
> > > >>
> > > >>
> > > >>
> > > >>>How to make traffic dropped aggressively?
> > > >>>
> > > >>>
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