Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

How do you tell if a 3750 interface is shaping or policing traffic?

We have an Avaya PBX Medpro board plugged into a 3750 port with the following configuration:

interface FastEthernet1/0/4

description PBX Medpro-1

switchport access vlan 10

switchport mode access

duplex full

speed 100

srr-queue bandwidth share 10 10 60 20

srr-queue bandwidth shape 10 0 0 0

mls qos trust dscp

auto qos voip trust

Everything was working fine until the PBX call level went above 110 calls (G-711) which pushed the interface to more than 10mbps. When this happened random calls out of that medpro became garbled and after lots of troubleshooting we came to the conclusion that the default auto qos settings where the problem.

Default auto qos puts these statements on an interface:

srr-queue bandwidth share 10 10 60 20

srr-queue bandwidth shape 10 0 0 0

...which means that queue 1 will allow for 10mbps of traffic and then shaping will kick in.

Adding the line 'priority-queue out' to the interface disables the 10mbps limitation of queue 1 and instead forces the interface to process every packet that goes into the priority queue before anything else.

My question is - is there a 'show' command that we can use to see shaping at work? On router ports with a service policy that has shaping or policing on it you can see the shaping/policing in real time with 'show policy....'

What about on the 3750 switch ports?

2 REPLIES
Bronze

Re: How do you tell if a 3750 interface is shaping or policing t

I've had issues many times with mepros/clan not tagging correctly. (phones you can trust all night and day)

Avaya recommends tagging at the port not trusting medpro/clan, so do not use mls qos trust dscp.

my interfaces for medpro/clan look somewhat like this:

interface FastEthernet

speed 100

duplex full

switchport access vlan

mls qos cos 5

mls qos cos override

spanning-tree portfast

no cdp enable

New Member

Re: How do you tell if a 3750 interface is shaping or policing t

Thanks for responding. We work with DSCP so I tried your example on the port a medpro is connected to, but with DSCP, as in:

int f0/15

description Medpro-1

switchport access vlan 12

mls qos dscp 46

srr-queue bandwidth share 10 10 60 20

srr-queue bandwidth shape 10 0 0 0

auto qos voip trust

This is the output of 'sh mls qos int f0/15'

#sh mls qos int f0/15

FastEthernet0/15

trust state: not trusted

trust mode: not trusted

trust enabled flag: ena

COS override: dis

default COS: 0

DSCP Mutation Map: Default DSCP Mutation Map

Trust device: none

qos mode: port-based

Note - it doesn't show that 'mls qos dscp 46' did anything. Also it won't take the command 'mls qos dscp override', so how do I tell to mark incoming packets to DSCP 46?

176
Views
0
Helpful
2
Replies
CreatePlease login to create content