I’ve cracked Cat QoS with the help of my mentor Arun, CCIEx2 ….Thank you!!!


PART 1: QOS AND VOIP

Step 1. Enable mls qos globally

6509-Access(config)# mls qos

Step 2. Select a port to configure.

6509-Access(config)#interface fastethernet 5/1

Step 3. Configure the port as a Layer 2 port in the access mode.

6509-Access(config-if)#switchport mode access

Step 4. Define the voice VLAN.

6509-Access(config-if)#switchport voice vlan 111

Step 5. Define the data VLAN.

6509-Access(config-if)#switchport access vlan 11

Step 7. Accept the incoming Layer 2 CoS. This lets the switch accept the phone marking of voice traffic at CoS = 5 and voice control traffic at CoS = 3 and enables input scheduling.

6509-Access(config-if)#mls qos trust cos

Step 8. Instruct the IP phone to rewrite the PC traffic to CoS = 0.

6509-Access(config-if)#mls qos trust extend cos 0

OR USE

to change the qos of a pc hanging off a phone use: switchport priority extend cos

This exmple shows how to set the phone that is attached to the switch port in trust mode:

PART 2: QOS AND VOIP

To remark DSCP markings:

mls qos map dscp-mutation dscp-mutation-name in-dscp to out-dscp

Switch(config)# mls qos map dscp-mutation gi0/2-mutation 10 11 12 13 to 30
Switch(config)# interface gigabitethernet0/2
Switch(config-if)# mls qos trust dscp
Switch(config-if)# mls qos dscp-mutation gi0/2-mutation

OR

mls qos map cos-dscp 10 15 20 25 30 35 40 45

OR

mls qos map ip-prec-dscp 10 15 20 25 30 35 40 45

I hope this helps

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