Auto qos on 3550

[ciscoforum]

Port 0/11 attached one ip phone and no pc behind the phone. Show mls qos inter fas 0/11 sta shows there are packetd classifed as dscp0, by doing math I found the packets classfied as dscp0 is from dscp26:1690-1618. DSCP26 is sccp for sure, but why some are classfied to dscp0, and the rest not. Also I noticed there are a lot of other packets. what else other traffic will be, there are only either dscp 0, dscp 26 or 46. Thanks

interface FastEthernet0/11

switchport trunk encapsulation dot1q

switchport trunk native vlan 102

switchport mode trunk

switchport voice vlan 202

no ip address

mls qos trust device cisco-phone

mls qos trust cos

mls qos monitor dscp 0 24 26 32 40 46 48 54

auto qos voip cisco-phone

wrr-queue bandwidth 20 1 80 1

wrr-queue min-reserve 1 5

wrr-queue min-reserve 2 6

wrr-queue min-reserve 3 7

wrr-queue min-reserve 4 8

wrr-queue cos-map 1 0 1 2 4

wrr-queue cos-map 3 3 6 7

wrr-queue cos-map 4 5

priority-queue out

spanning-tree portfast

3550-24#sh mls qos inter fas 0/11 sta

FastEthernet0/11

Ingress

dscp: incoming no_change classified policed dropped (in bytes)

0 : 670 670 472 0 0

24: 0 0 0 0 0

26: 1690 1218 0 0 0

32: 0 0 0 0 0

40: 0 0 0 0 0

46: 0 0 0 0 0

48: 0 0 0 0 0

54: 0 0 0 0 0

Others: 655265 189221 466044 0 0

Egress

dscp: incoming no_change classified policed dropped (in bytes)

0 : 25477 n/a n/a 0 0

24: 0 n/a n/a 0 0

26: 0 n/a n/a 0 0

32: 0 n/a n/a 0 0

40: 0 n/a n/a 0 0

46: 0 n/a n/a 0 0

48: 0 n/a n/a 0 0

54: 0 n/a n/a 0 0

Others: 32443097 n/a n/a 0 0

[Aaron Harrison]

The CoS 0 traffic would likely be layer 2 stuff like CDP...

How have you got your cos-dscp map configured?

Aaron

[ciscoforum]

I found out the traffic on the "others" actually is before I turned on the dscp monitor command. I cleared the statistis and run the show again , there is no more "other" packets again. thanks a lot. I believe you are right the dscp 0 is CDP.

[jjia]

Based on the above configuration, and the show result, I found that some dscp 26 incoming traffic has been classfied as dscp 0. How does it come?

Can anyone tell me of this?

Thanks,

JJ

[ciscoforum]

Hi Aaron

This is the map:

mls qos map cos-dscp 0 8 16 26 32 46 48 56

It doesn't make sense some of the DSCP26 classified as DSCP0, and the rest not.

Btw, please ignore my another replied thread.

[Aaron Harrison]

Can you post the new show output?

[jjia]

Hi,

I found the commands of "mls qos trust cos" and "service-policy input" are exclusive. When I put the command of "mls qos trust cos" in the interface, then the previous command of "service-policy input" command has been removed automatically and I got the following result:

Switch3550#sh mls qos int f0/2 st

FastEthernet0/2

Ingress

dscp: incoming no_change classified policed dropped (in bytes)

0 : 5256 5256 560 0 0

8 : 0 0 0 0 0

16: 0 0 0 0 0

24: 0 0 0 0 0

26: 11890 11330 0 0 0

32: 0 0 0 0 0

46: 0 0 0 0 0

56: 0 0 0 0 0

Others: 0 0 0 0 0

Egress

dscp: incoming no_change classified policed dropped (in bytes)

0 : 155359 n/a n/a 0 0

8 : 0 n/a n/a 0 0

16: 0 n/a n/a 0 0

24: 0 n/a n/a 0 0

26: 0 n/a n/a 0 0

32: 0 n/a n/a 0 0

46: 0 n/a n/a 0 0

56: 348028 n/a n/a 0 0

Others: 1020 n/a n/a 0 0

So looks that 560 bytes have been classfied as dscp 0.

But if I enter "service-policy input" command, then the command of "mls qos trust cos" has been removed but the classfication is as expected, however there is no traffic on the colum of "Policed"

Can you tell me why?

Thanks.

JJ