09-01-2013 04:46 PM - edited 03-07-2019 03:15 PM
Hi,
I am doing a lab test to verify QOS on a Cisco 2960s 49P switch. The service policy applied to the interface Gi1/0/1 seems to be working as Wireshark capture (on the uplink trunk ports) indicate all traffic is correctly marked ("ef" for testint purposes). However, none of the counters in "show policy-map int gi1/0/1" seems to be increasing.
Standard IP access list acl-01
10 permit any
Class Map match-all cm-01 (id 4)
Match access-group name acl-01
Policy Map pm-01
Class cm-01
set dscp ef
interface GigabitEthernet1/0/1
switchport access vlan 240
switchport mode access
switchport voice vlan 234
spanning-tree portfast
service-policy input pm-01
#show policy-map interface gi1/0/1
GigabitEthernet1/0/1
Service-policy input: pm-01
Class-map: cm-01 (match-all)
0 packets, 0 bytes
5 minute offered rate 0 bps, drop rate 0 bps
Match: access-group name acl-01
Class-map: class-default (match-any)
0 packets, 0 bytes
5 minute offered rate 0 bps, drop rate 0 bps
Match: any
0 packets, 0 bytes
5 minute rate 0 bps
#show mls qos
QoS is enabled
QoS ip packet dscp rewrite is enabled
#show mls qos interface gi1/0/1
GigabitEthernet1/0/1
Attached policy-map for Ingress: pm-01
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
#show ver
Switch Ports Model SW Version SW Image
------ ----- ----- ---------- ----------
* 1 52 WS-C2960S-48LPS-L 15.0(2)SE2 C2960S-UNIVERSALK9-M
Has anyone else observed this ? A bug ?
Regards,
Rick.
Solved! Go to Solution.
09-01-2013 05:00 PM
Hi Rick,
I believe this is normal behavior. On switches, many operations including QoS marking manipulation is performed in hardware while the show policy-map command shows you the software counters associated with the policy-map. As the hardware does not report back the number of packets handled by the policy-map (which could be quite intensive as these operations are performed at wire rate), the counters in the policy-map are not incremented. The same goes, for example, for ACLs - the counters displayed by individual ACL entries do not increase, either.
If you check out the command reference for this command at:
the documentation says: Though visible in the command-line help string, the control-plane and interface keywords are not supported, and the statistics shown in the display should be ignored.
Best regards,
Peter
09-01-2013 05:00 PM
Hi Rick,
I believe this is normal behavior. On switches, many operations including QoS marking manipulation is performed in hardware while the show policy-map command shows you the software counters associated with the policy-map. As the hardware does not report back the number of packets handled by the policy-map (which could be quite intensive as these operations are performed at wire rate), the counters in the policy-map are not incremented. The same goes, for example, for ACLs - the counters displayed by individual ACL entries do not increase, either.
If you check out the command reference for this command at:
the documentation says: Though visible in the command-line help string, the control-plane and interface keywords are not supported, and the statistics shown in the display should be ignored.
Best regards,
Peter
09-01-2013 05:06 PM
Thanks Peter. That explains the behaviour.
Regards,
Rick.
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