rate limiting on an ethernet interface

mtp337 · ‎04-08-2010

Hi Folks,

I need a little help, verification. We have some 6509's with MSFC's running a bunch on virtual interfaces and we want to limit the bandwidth on one vlan/interface. Here is my interface config:

interface Vlan110

description slow lane

ip address 10.1.110.2 255.255.255.0

no ip redirects

no ip unreachables

rate-limit input 8000 1500 2000 conform-action transmit exceed-action drop

rate-limit output 8000 1500 2000 conform-action transmit exceed-action drop

standby 110 ip 10.1.110.1

standby 110 priority 220

standby 110 preempt

When I test file downloads on this vlan I am still getting around 200 KB/s. Yet I was expecting way less with the above config. So I checked to see if

the interface is showing the limits:

hono-rhp-hb-gw01#sho interfaces vlan 110 rate-limit

Vlan110

Input

matches: all traffic

params: 8000 bps, 1500 limit, 2000 extended limit

conformed 0 packets, 0 bytes; action: transmit

exceeded 0 packets, 0 bytes; action: drop

last packet: 15253688ms ago, current burst: 0 bytes

last cleared 00:31:58 ago, conformed 0 bps, exceeded 0 bps

Output

matches: all traffic

params: 8000 bps, 1500 limit, 2000 extended limit

conformed 1069 packets, 126834 bytes; action: transmit

exceeded 0 packets, 0 bytes; action: drop

last packet: 1060ms ago, current burst: 0 bytes

last cleared 00:31:58 ago, conformed 0 bps, exceeded 0 bps

Yet I can download 200 meg files in less than 15 minutes...?

Giuseppe Larosa · ‎04-08-2010

Hello MTP337,

there are some aspects that need to be addressed:

exactly what type of supervisor and IOS image is on the C6509?

depending on the HW and IOS image the MSFC Vlan SVI can see only process switched packets and not packets that are switched by multilayer switching this would explain your results.

Another important point is the two endpoints used in the file transfer if they are in the same IP subnet the multilayer switch SVI is not involved in the process.

Also for multilayer switched packets you need to use different QoS tools that are applied to the PFC policy feature card that has its own QoS capabilities and features.

So it is likely you need to configure policers for PFC module in the supervisor at port level or at vlan level (L2 broadcast domain)

see

http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2SXF/native/configuration/guide/qos.html#wp1516886

Hope to help

Giuseppe