about "srr-queue bandwidth limit XX"

[TetsuNishimura]

Hello, All
I have a switch(WS-C2960XR-24TS-I/15.2(2)E3),
and set Shaped Round Robin as follow.

----------------------------------------
interface GigabitEthernet1/0/1
 speed 100
 duplex full
 srr-queue bandwidth share 60 10 20 10
 srr-queue bandwidth shape  0 0 0 0
 srr-queue bandwidth limit 10
 priority-queue out
 mls qos trust ip-precedence
----------------------------------------

Does command"srr-queue bandwidth limit 10" affects the bandwidth of the interface set in the command"speed" ?
Speaking in the above example, is following correct?
that Because "speed 100" and " srr-queue bandwidth limit 10 "setting,
it will be a interface with a bandwidth of 10Mbps (10% of the 100Mbps)

Thanks.

[Joseph W. Doherty]

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Posting

Yes it does.  Your egress (not ingress) bandwidth will be limited (to about) 10% of the physical egress bandwidth.  So, as you noted, if your interface is running at 100 Mbps, your egress will obtain (about) 10 Mbps.

The reason "about", above, is used is because on 3560s/3570s, they note the bandwidth limit is not exact.  The same may apply to the 2960XR (look for a note in the config guide or reference manual, for this command).

[TetsuNishimura]

Hello Joseph,
I had overlooked for the point of view of output and input
Thank you for your answer!

[Erico Verissimo]

Hi Tez,

It means the speed configured, in this case 100Mbps, it will be limited in 10 percent. So, you can traffic on 10Mbps.

Regards. 

[Erico Verissimo]

I was wrong, sorry.. Your output will obtain 10Mbps.

These values are not exact because the hardware adjusts the line rate in increments of six.

This link can help you:

http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3750/software/release/12-2_55_se/commmand/reference/3750cr/cli3.html#pgfId-1947391

[TetsuNishimura]

Hello Erico,
Thank you for your answer and CCO LINK,
I will be reading!

[sbhadrav@cisco.com]

You can use the "srr-queue bandwidth limit xx" command to limit the bandwidth but the values are from 10-100 so if you want to limit your bandwidth to 1 meg, you need to configure the speed of the interface to 10 meg.
int gi0/1
speed 10
srr-queue bandwidth limit 10
You will probably have to enable "mls qos" globally to have this feature work, in which case you'll automatically get the default queue configuration. I would be very cautious turning this on without testing because once your traffic goes over 1meg, the switch will then use its default egress queue policy which may not be a policy that works for you. I found the defaults to be less that steller, like dropping tos 7 and 4 before dropping tos 0. Just be aware that there is a default policy even though it doesn't show in the running config.
Check out the qos section of the config guide.
http://www.cisco.com/en/US/docs/switches/lan/catalyst3560/software/release/12.2_46_se/configuration/guide/swqos.html