C2960 - LanLite QOS

Unanswered Question
Feb 21st, 2010

Hi,

pls help me,

3th party phones (snom?) are connectet to my switch

no mls qos

!

int fast0/2

switchport access vlan 2 (for data)

switchport voice vlan 33 (for voice)

but my problem is, all DCSP's through the switch in both directions are set to DSCP 0.

Phone (5) ----> switch ----> input Routerinterface (0)

Router (5) ----> switch ----> Phone (0)

the switch changes all dscp to zero, why? what can i do?

thx goody40

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Lei Tian Sun, 02/21/2010 - 07:42

Hi goody40,

Disable qos globally will make the switch transparent pass the DSCP value. It will not change DSCP.

If you want to use qos feature on the switch, you need to enable qos globally first by using

mls qos

After you enable qos globally, the switch will put all ports into untrust state by default, and it will re-write the COS/DSCP to 0 for all traffic. If you know your phone is marking correctly, you can put the phone port on your switch into trust DSCP state. If you want to mark traffic based on different traffic type then you need to apply policy-map under interface to mark traffic to the DSCP you want.

Please read the configuration guide for detail.

http://www.cisco.com/en/US/docs/switches/lan/catalyst2960/software/release/12.2_52_se/configuration/guide/swqos.html

HTH,

Lei Tian

Jon Marshall Sun, 02/21/2010 - 08:02

goody40 wrote:

Hi,

pls help me,

3th party phones (snom?) are connectet to my switch

no mls qos

!

int fast0/2

switchport access vlan 2 (for data)

switchport voice vlan 33 (for voice)

but my problem is, all DCSP's through the switch in both directions are set to DSCP 0.

Phone (5) ----> switch ----> input Routerinterface (0)

Router (5) ----> switch ----> Phone (0)

the switch changes all dscp to zero, why? what can i do?

thx goody40

Are you sure the packets are being marked with DSCP value. If you disable QOS as you have done on the 2960 then all markings in packets should be left as they are.

Jon

Leo Laohoo Sun, 02/21/2010 - 13:09

Errrr ... correct me if I'm wrong.  But you are using LanLite and you want QoS for voice?  I believe LanLite QoS is equivalent to a 2950 running Standard Image.  It's very crude and basic.

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