[c-nsp] qos on cat2950

[Roman Bestuzhev]

Thanks for information.

I searched the list for 2007-2006 and couldn't find that discussion, only
several topics about various qos aspects on 2950/2960. Nothing about buffers
tuning. Is it possible that the discussion is in older archives?

I also tried to google something about qos & buffers & 2950 but couldn't
find anything useful. Moreover, there is IOS command buffers, which can be
used to tune buffers on cisco device, including cat2950. I am going to play
with it. But there is nothing about it in cisco documentation for 2950
switches for 12.1(22)EA2 (this IOS version is used on my device) and older
releases. That's strange.

2007/7/5, Higham, Josh <jhigham at epri.com>:
>
> I believe the problem may be due to small buffers; there was a
> discussion on this list recently regarding maximum rates for policed
> traffic.
>
> Not sure, but hope it helps.
>
> Thanks,
> Josh
>
> > -----Original Message-----
> > From: cisco-nsp-bounces at puck.nether.net
> > [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Roman
> > Bestuzhev
> > Sent: Thursday, July 05, 2007 1:58 AM
> > To: cisco-nsp at puck.nether.net
> > Subject: [c-nsp] qos on cat2950
> >
> > Hello,
> >
> > I'm trying to configure qos on 2950 to restrict speed for
> > several users who
> > sit on 10/100 ports. For example for only 8Mb/s for traffic
> > in direction to
> > the users. Testing tools are iperf and ftp/http downloads/uploads.
> >
> > To achive this I configure my switch in the following way:
> >
> > 1. Configure access-list to choose particular user:
> >
> > #access-list 199 permit ip any 192.168.0.0 0.0.0.255
> >
> > 2. Configure class-map for this user:
> >
> > #class-map match-all cl-user
> > #match access-group 199
> >
> > 3. Configure policy-map to tie speed policy 8Mb/s and burst 8192 with
> > particular user:
> >
> > #policy-map pol-input
> > #class cl-user
> > #police 8000000 8192 exceed-action drop
> >
> > 4. Finally, I assign this policy to gigabit interface which
> > is configured as
> > trunk to the network core switch (currently cat 3750). This
> > port receives
> > traffic from other parts of the network to the local users.
> >
> > #int gi0/X
> > #service-policy input pol-input
> >
> > At this moment switch starts policing traffic but result is strange.
> > Download speed is about 250Kbit/s (about 8 mb/s expected). If
> > I increase
> > burst parameter speed is getting faster:
> > burst:  32768, speed: about 900 Kbit/s
> > burst: 131072, speed: about 3.5 Mb/s
> > burst: 262144, speed: about 5.4 Kbit/s
> >
> > If I try to restrict upload speed by configuring policers on
> > 10/100 ports
> > results are more starnge: For example this command restrict
> > upload speed to
> > approximately 2.5 Mb/s but it brobabely should be about 20 Mb/s:
> >
> > #police 20000000 65536 exceed-action drop
> >
> > The questions are:
> >
> > Do I missunderstand something? Is this behavior usual? Or
> > 2950 doesn't have
> > enough functionality to perform policing well? And would
> > 3550/2560 or 3750
> > catalysts (upstream switches) be better choices to achieve my goal if
> > configure qos on them instead of 2950?
> >
> > Thanks in advance for any comments/ideas.
> >
> >
> > --
> > Roman Bestuzhev,
> > System Administrator
> > _______________________________________________
> > cisco-nsp mailing list  cisco-nsp at puck.nether.net
> > https://puck.nether.net/mailman/listinfo/cisco-nsp
> > archive at http://puck.nether.net/pipermail/cisco-nsp/
> >
>



-- 
Roman Bestuzhev,
System Administrator