bandwidth limiting 1

[nix45]

Is it possible to limit the amount of bandwidth that gets passed through an interface? I have a Cisco 1700 series router with 2 Ethernet interfaces. For testing purposes, I want to limit the bandwidth on one of the interfaces to 256K. Is this possible?

If not, I'll just set up a Squid proxy on a Linux server to do it.

Thanks,
Chris

 

[rburke]

Look into the "rate-limit" command on the interface. Sorry I don't have the Cisco link or any other details, but I have implemented it before and it was very easy to do. I remember it has the ability to limit based on MAC address, access-list and the entire interface.

Burke

 

[nix45]

I was looking at the rate-limit command on the router, but I'm a little unsure on how to restrict the connection to 256K. Here's the rate-limit options...


cis2621ny1(config-if)#rate-limit ?
input Rate limit on input
output Rate limit on output

cis2621ny1(config-if)#rate-limit input ?
<8000-2000000000> Bits per second
access-group Match access list
dscp Match dscp value
qos-group Match qos-group ID

cis2621ny1(config-if)#rate-limit input 256000 ?
<1000-512000000> Normal burst bytes

cis2621ny1(config-if)#rate-limit input 256000 256000 ?
<2000-1024000000> Maximum burst bytes

cis2621ny1(config-if)#rate-limit input 256000 256000 256000 ?
conform-action action when rate not exceeded

cis2621ny1(config-if)#rate-limit input 256000 256000 256000 conform-action ?
continue scan other rate limits
drop drop packet
set-dscp-continue set dscp, scan other rate limits
set-dscp-transmit set dscp and send it
set-mpls-exp-continue set exp during imposition, scan other rate limits
set-mpls-exp-transmit set exp during imposition and send it
set-prec-continue rewrite packet precedence, scan other rate limits
set-prec-transmit rewrite packet precedence and send it
set-qos-continue set qos-group, scan other rate limits
set-qos-transmit set qos-group and send it
transmit transmit packet

cis2621ny1(config-if)#rate-limit input 256000 256000 256000 conform-action continue ?
exceed-action action when rate exceeded

cis2621ny1(config-if)#rate-limit input 256000 256000 256000 conform-action continue



Thanks,
Chris

 

[rburke]

Here is what you would need to add to limit both the incoming and outgoing to 256k.

&quot;rate-limit input 256000 1000 2000 conform-action transmit exceed-action drop&quot;

&quot;rate-limit output 256000 1000 2000 conform-action transmit exceed-action drop&quot;

Let me know if this helps.

Burke

 

[nix45]

Thanks, I actually just called Cisco tech support and asked them a few minutes ago and they sent me almost the same command.

rate-limit output 256000 48000 48000 conform-action transmit exceed-action drop

His formula for calculating the burst was...

normal burst = cir X 1.5 / 8

256000 X 1.5 / 8 =s 48000 bytes extra in a given time slot

Thanks,
Chris

 

[rburke]

Glad I could help.

Burke

 

[tbilan]

Rate-limit is good for ethernet but later on if you want to do some elaborate solutions on the WAN side check out policy-maps and LLQ. It can classify different types of traffic and shape their throughput to meet your needs. So if I have a T1 to the home office I can shape (limit) web traffic to 256k, give citrix traffic a priority over every other type of traffic, guarantee 300k to 3270 telnet and the anything else that isn't classified goes into the default which uses the rest of the bandwidth.

http://www.cisco.com/en/US/partner/...figuration_guide_chapter09186a00800bd8f0.html

Tom Bilan
TJBA, Inc.
CCNP, CCDP, MCSE & CNE