Re: Priority queue

From: Ryan O'Connell (ryan-nsp@complicity.co.uk)
Date: Wed May 22 2002 - 10:41:49 EDT


On Wed, 22 May 2002 14:11:14 +0000 Felix Lee <felixlee_hk@hotmail.com> wrote:
> Dear all,
>
> I have a Catalyst 6509 running with Fw 5.4(2) & NmpSW 5.5(11). And the
> MSFC is running on 12.1(3a)E4.
>
> One strange point that cannot be explained is the priority queue applied
> on
> a VLAN which is connection to a WAN 100Mbps fastethernet.
> The priority queue is to put the FTP traffic low priority. After
> applying
> the priority queue, the time for a daily FTP job has been extended from
> 3
> hours to 5 hours while the traffic loading of the link is only around
> 10%.
> The duration come back to 3 hours after removing the priority queue.
>
> Can someone help to give advice?

With priority queueing, the traffic in the low queue (The FTP transfer)
will never get sent until all other queues are empty. This means that even
a low level of traffic, such as ssh, web or telnet sessions will delay the
traffic - the router won't continue sending any FTP traffic until *all* the
other traffic has gone.

You probably want to look into custom queueing, which allows better control
of what proportion of packets of each type are forwarded.

--
         Ryan O'Connell - CCIE #8174
<ryan@complicity.co.uk> - http://www.complicity.co.uk

I'm not losing my mind, no I'm not changing my lines, I'm just learning new things with the passage of time



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