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3 CoS to layer 2 QoS

How does one map layer 3 CoS to layer 2 QoS in their ATM network?


New Member

Re: 3 CoS to layer 2 QoS

There is not a direct mapping of L3 to ATM. You would have to understand the requirements for the type of traffic that you are transporting and then build an ATM PVC (CBR, VBR, ABR, UBR, etc.) to meet those requirements.

New Member

Re: 3 CoS to layer 2 QoS

MPLS will do it dynamically for ATM to map the layer 3 IP QoS to ATM QoS, if you have Cisco ATM network (BPX, MGX, IGX), you need to add a MPLS LSC (lable switch controller). BTW, in QoS terminology, CoS is usually a layer 2, ToS/DiffServe is a layer 3.

New Member

Re: 3 CoS to layer 2 QoS

Take a look at the IOS 12.2 QOS configuration guide. Theres a section on IPtoATM CoS mapping. Its a pig to understand the first time you look at it.

Basically you can create a bundle of different VCs each with their own QoS through the ATM network and then split out different CoS policies onto those VCs.

Hope that helps. I would give more info but Im just getting through it myself and Im not sure Ive got it configured entirely correctly.

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