From: Daniel Shin (dshin@xxxxxxxxx)
Date: Mon Feb 26 2001 - 16:02:17 GMT-3
The first value is the actual rate limit. Second value is what you allow them
to burst up to. And the third one is if there is a credit from previous second
,
then how much more would you allow them to burst. All the values added togethe
r
is your total car.
However, going back to the first question, Catalysts do not support CAR. They
have vlan interfaces that are (literally virtual interface and there is no
physical port associated with them). When a train of packets arrive, the first
packet will go through the vlan interface to be routed and the rest of packets
get fastswitched at the wire rate on the switch. That's why the catalysts can
route packets so much faster than 7500 or 7200 due to that architecture. They
literally switch packets at a wire rate (the same switching as a layer 2).
Downside is that the vlan never sees the full traffic going through. So CAR is
not possible on a catalyst because it will never reach the rate-limit to be
discarded.
> From dp595@optonline.net Mon Feb 26 10:40:48 2001
> Date: Mon, 26 Feb 2001 13:40:03 -0500
> From: Dan <dp595@optonline.net>
> Subject: Re: Rate-limiting on Cat6K (off topic)
> To: Daniel Shin <dshin@cisco.com>, ccielab@groupstudy.com
> MIME-version: 1.0
> X-MIMEOLE: Produced By Microsoft MimeOLE V5.50.4133.2400
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>
> 6509 Running IOS, and I think I had the burst rates wrong in my example
> below. I want 9MB of burst, therefore 1125000 bytes of burst (not 1250000).
> Am I using the correct logic here?
>
> Dan Pontrelli
> Customer Installation Engineer - Verio NYC
> CCNP, MCSE, CNA
>
> ----- Original Message -----
> From: "Daniel Shin" <dshin@cisco.com>
> To: <ccielab@groupstudy.com>; <dp595@optonline.net>
> Sent: Monday, February 26, 2001 1:12 PM
> Subject: Re: Rate-limiting on Cat6K (off topic)
>
>
> > Are you running hybrid or native IOS?
> >
> > Answers embedded...
> >
> >
> > > From nobody@groupstudy.com Mon Feb 26 09:25:22 2001
> > > Date: Mon, 26 Feb 2001 12:18:16 -0500
> > > From: Dan <dp595@optonline.net>
> > > Subject: Rate-limiting on Cat6K (off topic)
> > > To: ccielab@groupstudy.com
> > > X-MIMEOLE: Produced By Microsoft MimeOLE V5.50.4133.2400
> > > X-Priority: 3
> > > X-MSMail-priority: Normal
> > >
> >
> > CAR is not supported due to achitecture of catalysts.
> >
> > > I am trying to rate-limit a connection on a Cat6K FastEthernet port.
> > > I want 1MB bandwidth burstable to 10MB. I looked at the Cisco website
> and I
> > > think the following would do the trick:
> > >
> > > rate-limit input 1000000 1250000 1250000 conform-action transmit
> > > exceed-action drop
> > > rate-limit output 1000000 1250000 1250000 conform-action transmit
> > > exceed-action drop
> > >
> > > Is this correct? I'm still having trouble understanding why 2 burst
> rates
> > > (normal and maximum) need to be specified.
> > >
> >
> > If you don't, you will end up rate-limiting more traffic than intended.
> Think
> > about the traffic pattern. It bursts up and down - especially FTP.
> >
> > > Thanks in advance for any input.
> > >
> > >
> > > Dan Pontrelli
> > > Customer Installation Engineer - Verio NYC
> > > CCNP, MCSE, CNA
> > >
> > >
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