QoS Question

Unanswered Question
Mar 24th, 2010
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Hi folks:



3550 switch running 12.2.35 SE5



Have this QoS config:


ip access-list extended DATA
  permit udp any any eq netbios-ns
  permit udp any any eq netbios-dgm
  permit udp any any eq netbios-ss
  permit tcp any any eq telnet
  permit tcp any any eq www
  permit tcp any any eq 443
  permit tcp any any eq 22
  permit tcp any any eq ftp


class-map match-any DATA_CLASS_MAP
  match access-group name DATA
!
!
policy-map SET_DSCP_MICROSOFT_TRAFFIC
  class DATA_CLASS_MAP
   set dscp af41

!


!

interface FastEthernet0/3
switchport access vlan 10
switchport mode access
speed 100
duplex full
service-policy input SET_DSCP_MICROSOFT_TRAFFIC





I plugged my laptop into fa0/3 and generated all kinds of traffic to match the ACL for the class map...ran some telnets, pings, opened windows explorer, ran telnet on port 80, etc...


But I get no hits on the service policy on that interface:


Switch1#sh policy-map  interface fa0/3 input
FastEthernet0/3


  Service-policy input: SET_DSCP_MICROSOFT_TRAFFIC


    Class-map: DATA_CLASS_MAP (match-any)
      0 packets, 0 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: access-group name DATA
        0 packets, 0 bytes
        5 minute rate 0 bps


    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
3550#


How come?


Thanks

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ex-engineer Wed, 03/24/2010 - 13:00
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3550#show mls qos interface fa0/3 statistics
FastEthernet0/3
Ingress
  dscp: incoming   no_change  classified policed    dropped (in bytes)
Others: 0          0          0          0          0
Egress
  dscp: incoming   no_change  classified policed    dropped (in bytes)
Others: 0             n/a       n/a      0          0


3550#


Nothing......

ex-engineer Wed, 03/24/2010 - 13:17
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Not stupid at all...I forgot to enable qos...


Now that I did, this is what I get:



3550#SH POLICy-map interface fa0/3 input

FastEthernet0/3


  Service-policy input: SET_DSCP_MICROSOFT_TRAFFIC


    Class-map: DATA_CLASS_MAP (match-any)

      0 packets, 0 bytes

      5 minute offered rate 0 bps, drop rate 0 bps

      Match: access-group name DATA

        0 packets, 0 bytes

        5 minute rate 0 bps


    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

3550#

3550#

3550#

3550#

3550#show mls qos interface fa0/3 statistics

FastEthernet0/3

Ingress

  dscp: incoming   no_change  classified policed    dropped (in bytes)

Others: 262        0          262        0          0

Egress (??)

  dscp: incoming   no_change  classified policed    dropped (in bytes)

Others: 6283          n/a       n/a      0          0


3550#


I didnt set any egree policy......and I dont understand how to read this output..and it also seems to contradict the first command output...

Lei Tian Wed, 03/24/2010 - 13:17
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  • Cisco Employee,

Hi ex-engineer,


You need to

1, make sure qos is enabled.

2, configure mls qos monitor dscp 34 under the interface, and use the above command to check if traffic been marked to af41.


HTH,

Lei Tian

ex-engineer Wed, 03/24/2010 - 13:29
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3550#show mls qos interface fa0/3 statistics
FastEthernet0/3
Ingress
  dscp: incoming   no_change  classified policed    dropped (in bytes)
    34: 0          0          0          0          0
Others: 522        0          522        0          0
Egress
  dscp: incoming   no_change  classified policed    dropped (in bytes)
    34: 0             n/a       n/a      0          0
Others: 40299         n/a       n/a      0          0


thanks


I still dont understand how to interpret these statistics...what is this telling me?

ex-engineer Wed, 03/24/2010 - 13:32
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And why no stats using this command


sh policy-map int fa0/3 input
FastEthernet0/3


  Service-policy input: SET_DSCP_MICROSOFT_TRAFFIC


    Class-map: DATA_CLASS_MAP (match-any)
      0 packets, 0 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: access-group name DATA
        0 packets, 0 bytes
        5 minute rate 0 bps


    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

Lei Tian Wed, 03/24/2010 - 13:56
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  • Cisco Employee,

The QoS marking and ACL are done by hardware, or the ASIC. The show policy-map interface will not be able to capture the counter correctly, same is true for 3750s. This is one of the gotcha on these platform.


Regrading the meaning of the output,

dscp: incoming   no_change  classified policed    dropped (in bytes)


incoming: number of packets enter this interface that have dscp 34

no_change: number of packets keep dscp 34 after qos process

classified: number of packet been classified to dscp 34


For your case, your output shows none packet been marked as af41.


HTH,

Lei Tian

r.shummoogum Wed, 03/24/2010 - 13:40
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The packets are coming in with a DSCP other that 34 and is getting marked at the ingress. That is why it zero everywhere and non-zero for other.

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