QOS Configuration on Catalyst 3550

[VasifKasim0v]

Hi! I tried to limit bandwidth utilization on my 3550 switch.I configured class-map, created policy-map("bandwidth 64" command) for this class-map.But i can't attach it to the interface...Nothing comes up when i issue show mls qos interface fastethernet 0/1.(Qos enabled,port isn't trunk port.)Can anybody help to solve this proble.

[mheusinger]

Hi,

when you say "limit bandwidth utilization" you will need a policer or shaper. The command "bandwidth 64" does not do it.

You would need

policy-map test

class MaxRate

police 64000

as a minimum configuration. Have a look at

"Understanding QoS Policing and Marking on the Catalyst 3550"

http://www.cisco.com/en/US/products/hw/switches/ps646/products_tech_note09186a00800feff5.shtml

Hope this helps

Martin

[VasifKasim0v]

Hi Martin! and thanks for your reply.

But so can you explain me the purpose of bandwidth command?

This output from official CCNP Switching cource.

"The policy-map shown below creates a traffic policy named policy1. The policy applies to all traffic classified by the previously defined traffic-class “cisco” and specifies that traffic in this example should be allocated bandwidth of 3000 kbps.

Switch(config)#policy-map policy1

Switch(config-pmap)#class cisco

Switch(config-pmap-c)#bandwidth 3000

Switch(config-pmap-c)#exit

Note: The actual policies that can be implemented are platform dependent. The example given above is relevant for a Catalyst 3550 or Catalyst 6500 but the bandwidth command is not supported by the Catalyst 2950."

[mheusinger]

Hi,

the bandwidth command in a policy-map is to configure Weigthed Fair Queueing. It gives a minimum bandwidth guarantee - but no upper limit. So in case you want to give to f.e. HTTP traffic at least 3 MBit/s then the above example would be used. This would also allow 100 MBit/s HTTP traffic on a FastEthernet interface.

A policer gives an upper limit. In case you never want more than 3 MBit/s and drop excess traffic you would use "police 3000000" instead of "bandwidth 3000". (the commands use bps and kbps respectively).

Hope this helps

Martin

[nahas7211]

Hi,

I m trying to do bandwidth control on cisco catalyst 3550,i tried to do it with cli,i tried to do it policing.when i tried to create a class,i get the following error,i m using the firmware version "Version 12.1(22)EA1a". Cisco3550T24(config)#policy-map policy1

Cisco3550T24(config-pmap)#class cisco

class map cisco not configured.

Also how i can do bandwidth control using snmp.Please help

[johansens]

Hi there,

You should read this document as QoS has some limitations on the 3550-platform:

"Understanding QoS Policing and Marking on the Catalyst 3550"

http://www.cisco.com/en/US/products/hw/switches/ps646/products_tech_note09186a00800feff5.shtml

Did it help?