04-09-2011 10:50 AM - edited 03-04-2019 12:02 PM
Reposted from ServerFault.com, and ASK THE EXPERTS - QoS with Cisco expert Sarala Akella, where it didn't get an answer, except to confirm the omission of set-dscp-transmit from the 3560 manual.
I’m the chairman of the wiring committee for a hundred-unit condominium, andnot a Cisco expert. We have a trio of Cisco Catalyst 3550 switches, connected to an old Cisco 1417 router, connected to a DSL connection which we realize we need to upgrade. Our consultants configured, but did not enable, policing on each switch, so that each owner gets a guaranteed amount of bandwidth; once I enabled it (with mls qos), this seemed to work as documented:
policy-map USER_INGRESS
class ANY
police 32000 8000 exceed-action drop
policy-map USER_EGRESS
class DSCP0
police 96000 24000 exceed-action drop
But we were sold the switches on the basis that rationing would be more flexible when all the bandwidth wasn’t being used up, which this doesn’t seem to do.
Cisco IOS Quality of Service Solutions Command Reference 12.2 seems to suggest that set-dscp-transmit 0 might mark excess packets as best-effort, which I’d hoped would act sensibly at times of low usage. But it looks like this isn’t supported on our switches; trying to enable it gives % Invalid input detected at '^' marker at the beginning of set-dscp-transmit.
I might be able to offer more than just reputation points for hand-holding on followup issues; I’ve got a budget for some consulting hours, and might get approval for ongoing consulting.
04-18-2011 01:13 PM
The Cisco expert (Sarala Akella) was wrong; the 3550 does support policed-dscp-transmit, though I haven’t gotten it to work usefully yet, since I need to figure out mls qos map policed-dscp first.
Discover and save your favorite ideas. Come back to expert answers, step-by-step guides, recent topics, and more.
New here? Get started with these tips. How to use Community New member guide