QoS for MPLS traffic

[justanas1]

Hi All,

If i have two PE MPLS routers connected via Layer 2 switches and these switches provide only layer2 VLAN transport between these PE routers. Is it possible to configure DSCP based qos on the layer 2 switches to provide different kind of service for the traffic?

Because what i know if the data between the PE routers is MPLS labled "let’s say two labels one for the transport and one for the VPN" the Layer 2 switch will not be able to classify based on the L3 header, is this true?

Thanks

Anas

[Mohamed Sobair]

Anas,

Your describtion is correct, the layer-2 switch ust provides layer-2 connectivity in this case and is not used for any layer-3 marking. You need to start marking at the PE side.

Regards,

Mohamed

[justanas1]

Thanks Mohammad,

When the MPLS traffic comes from the PE to the L2 switch "example 3750", Can the L2 switch look deep inside the MPLS packet and match for example based on source IP or DSCP value?

[Mohamed Sobair]

Anas,

The (3750) is a L3 Switch, it can determine and mark at layer-3 , however, I dont believe this is your case here, your switch as per your describtion is to provide connectivity between PEs, isnt it?  or is it configured other wise? Could you elaborate on whats exactly you want to achieve in order to help you further?

Regards,

Mohamed

[justanas1]

Hi Mohammad,

The connection is as follows:

PE1 ----- 3750 ----(trunk)----3750-----PE2

PE1 and PE2 are in the same VLAN from 3750 side, is is VLAN10 and it is spanned over the trunk.

The trunk is serving another VLANs for other routers

I need to configure QoS on the link between the 3750 switches to give priority for VoIP. Can i classify using source IP or DSCP from data coming from PE1 cutomers and going to PE2 customers.

Thanks and regards,

Anas

[Mohamed Sobair]

In this type of scenario, you dont need marking at the Switch side. Your switches just provides connectivity between PEs.

All your marking and priority should be done on the customer and PE sides!

Regards,

Mohamed