Help me DSCP tag incoming packets on an ISR 1811 switchport

jesper_petersen · ‎10-19-2010

Hello peeps

I'm trying to tag all incoming packets received on a particular switchport with DSCP EF. There is a VoIP concentrator connected to that port, so I would like to tag all packets with EF, so that I can more easily prioritize them at the output interface (WAN). To my knowledge the VoIP concentrator does not tag the packets. Is there a way that I can see the tags handled by the internal switch? Like the "sh mls qos interface" on a Catalyst switch.

I have the following configuration but it does not seem to do the job:

class-map match-all MatchAllTraffic

match input-interface FastEthernet9

!

policy-map TagWithEF

class MatchAllTraffic

set ip dscp ef

!
interface FastEthernet9
description VoIP concentrator
load-interval 30
spanning-tree portfast
service-policy input TagWithEF
!

------- Output

CFFSA# sh policy-map interface fastEthernet 9
FastEthernet9

Service-policy input: TagWithEF

    Class-map: MatchAllTraffic (match-all)
      0 packets, 0 bytes
      30 second offered rate 0 bps, drop rate 0 bps
      Match: input-interface FastEthernet9
      QoS Set
        dscp ef
          Packets marked 0

    Class-map: class-default (match-any)
      0 packets, 0 bytes
      30 second offered rate 0 bps, drop rate 0 bps
      Match: any

----------

It seems like it does not like my applying the policy-map on the inbound direction?

I have also tried with an access-list (permit ip any any) instead of the "match input-interface fa9" in the Classmap clause.

Any one have any ideas why I cannot get it to work?

Best regards

Jesper

Dan-Ciprian Cicioiu · ‎10-19-2010

Hi ,

[later edit]

I see that you dont have any match on any of the classes.

You can try appling the policy on the SVI

Dan

jesper_petersen · ‎10-19-2010

Hi

Thanks for your reply.

I'm using the builtin 8-port switch that is in the Cisco 1811 router.

I have never used the switchport priority command.

Here is what I can gather that will help me to tag all incoming packets with COS 7:

RTR(config-if)#do sh run int fa9
Building configuration...

Current configuration : 165 bytes
!
interface FastEthernet9
description VoIP concentrator
switchport priority default 7
switchport priority override
load-interval 30
spanning-tree portfast
end

-------

RTR(config-if)#do sh int fa9 switchpor
Name: Fa9
Switchport: Enabled
Administrative Mode: static access
Operational Mode: static access
Administrative Trunking Encapsulation: dot1q
Operational Trunking Encapsulation: native
Negotiation of Trunking: Disabled
Access Mode VLAN: 1 (default)
Trunking Native Mode VLAN: 1 (default)
Trunking VLANs Enabled: ALL
Trunking VLANs Active: 1
Protected: false
Priority for untagged frames: 7
Override vlan tag priority: TRUE
Voice VLAN: none
Appliance trust: none

-----

Is there a way to verify this without using Wireshark?

Thank you for your tip

Best regards

Jesper

milan.kulik · ‎10-19-2010

Hi,

I believe your policy described in the original post would work if applied on an L3 interface.

But my understanding is your int fa9 is an L2 (switchport) interface only, isn't it?

So you would either have to make it na L3 (configure an IP address on it) or apply the policy on an SVI interface within the proper VLAN (i.e., int VLAN1).

I'm afraid the switch QoS commands would work on some standalone switches (see http://www.cisco.com/en/US/customer/docs/switches/lan/catalyst3560/software/release/12.2_25_se/configuration/guide/swqos.html#wp1162303 , .e.g) but not on the switch integrated into 1811 router.

BR,

Milan