From: Larry Roberts (larryr@netbeam.net)
Date: Wed Aug 20 2003 - 18:15:24 GMT-3
Brian,
By rate-limiting the FTP traffic, I mean using CAR to limit FTP to say 512k.
This action is in effect even when the link is not congested. I would
recommend this or WRED as suggested by phong. I wouldn't recommend LLQ or PQ
for web traffic as it is not interactive and doesn't care about dropped
packets or delay and jitter.
-Larry
----- Original Message -----
From: "Brian McGahan" <bmcgahan@internetworkexpert.com>
To: "'Larry Roberts'" <larryr@netbeam.net>; "'MMoniz'"
<ccie2002@tampabay.rr.com>; "'James Stewart'" <j_t_s_stewart@hotmail.com>;
<ccielab@groupstudy.com>
Sent: Wednesday, August 20, 2003 2:03 PM
Subject: RE: QoS on Router or Switch
> Larry,
>
> Rate-limiting the FTP traffic would not have any effect since
> the link is not congested. The only QoS mechanism that is constantly in
> effect even when there is no congestion is the priority queue. The
> priority queue includes the legacy priority queue, the low latency
> queue, and RTP.
>
> Another consideration when trying to answer this question is the
> direction of the FTP flow. Are clients receiving the FTP data or
> sending the FTP data? If we assume that the clients are downloading FTP
> data from the internet, and trying to access web services from the
> internet, the most effective place to apply a priority queue would be
> upstream, which in this case is R2.
>
> If you configure a low latency queue to prioritize web replies
> (source of TCP 80 not destination) from servers on the internet, this
> solution should be effective. You could also configure a legacy
> priority queue on R2, however then you run the risk of completely
> starving the FTP transfers if web replies are consistently in the higher
> queues.
>
>
> HTH,
>
> Brian McGahan, CCIE #8593
> bmcgahan@internetworkexpert.com
>
> Internetwork Expert, Inc.
> http://www.InternetworkExpert.com
> Toll Free: 877-334-8987
> Direct: 708-362-1418 (Outside the US and Canada)
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> Larry Roberts
> Sent: Wednesday, August 20, 2003 3:43 PM
> To: MMoniz; James Stewart; ccielab@groupstudy.com
> Subject: Re: QoS on Router or Switch
>
> That is why I recommended rate-limiting the FTP traffic instead. :-)
>
> -Larry
>
> ----- Original Message -----
> From: "MMoniz" <ccie2002@tampabay.rr.com>
> To: "Larry Roberts" <larryr@netbeam.net>; "James Stewart"
> <j_t_s_stewart@hotmail.com>; <ccielab@groupstudy.com>
> Sent: Wednesday, August 20, 2003 1:39 PM
> Subject: RE: QoS on Router or Switch
>
>
> > Jim,
> >
> > To me this sounds more like a WCCP solution. Since the link isn't
> congested
> > QOS will not really come into play, except of course for like
> bandwidth
> > amounts and such.
> >
> > -----Original Message-----
> > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
> > Larry Roberts
> > Sent: Wednesday, August 20, 2003 3:01 PM
> > To: James Stewart; ccielab@groupstudy.com
> > Subject: Re: QoS on Router or Switch
> >
> >
> > James,
> >
> > QoS is much easier to implement on a router as opposed to a switch. I
> would
> > also look at rate-limiting the FTP traffic so that it can only use up
> a
> > certain percentage of the bandwidth. Rate-limiting can be done either
> > inbound or outbound on the router, shaping can only be done outbound.
> >
> > HTH,
> > Larry Roberts
> > CCIE #7886 (R&S / Security)
> >
> > ----- Original Message -----
> > From: "James Stewart" <j_t_s_stewart@hotmail.com>
> > To: <ccielab@groupstudy.com>
> > Sent: Wednesday, August 20, 2003 11:52 AM
> > Subject: QoS on Router or Switch
> >
> >
> > > Hi
> > >
> > > Not sure where to apply the QoS.
> > >
> > > Users on a LAN on R1 complain that www access is slow.
> > > R1 is connected to the internet via a FR link to R2, which is not
> > congested.
> > > Users on the LAN are also backing up several servers using FTP over
> the
> > > same link.
> > >
> > > Should the QoS giving priority to www over ftp be implemented on the
> 3550
> > > switch egress port, ingress port of R1 or the egress of R1?
> > >
> > > Any ideas?
> > >
> > > Thanks Jim
> > >
> > > _________________________________________________________________
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