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Beginner

QoS Atm subinterface to Internet Policy Map Help

I have a 40meg connection to the Internet via 7200 router using ATM ubr.  I have been trying to design a Strict priorty for a particular subnet, then a 1 percent Scavenger Class the rest being class default with fair queue and random detect.

I can build the classes and policy maps yet the service-policy will not allow and inbound or outbound placement on the sub-interface.  Any help on this would be most appreciated.

Thanks

Jason

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Cisco Employee

Re: QoS Atm subinterface to Internet Policy Map Help

Hi Jason,

There are several ways to do this, I believe you have configure QoS using MQC?

If yes, the service policy probably needs to be configured under the PVC, is that what you tried? If yes, did you get any error message that would explain why you can't apply it?

Maybe this document can help understand where to apply the QoS:

http://www.cisco.com/en/US/tech/tk39/tk824/technologies_tech_note09186a00800d76b5.shtml

Thanks,

Raphael

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Beginner

Re: QoS Atm subinterface to Internet Policy Map Help

Thank you for the reply.  So if I understand the document correctly, ubr will no allow the placement of a service-policy command.  I would need to have both sides of the Internet line feed set to either vbr-nrt, vbr-rt, cbr or abs in order to apply a MQC service-policy.

Is this correct.  If it is then since the ATM line is a UBR from Qwest, changing the UBR to CBR does what to the Cell Transport?  Can you help on this as well.

Jason

Highlighted
Cisco Employee

Re: QoS Atm subinterface to Internet Policy Map Help

That's correct, CBWFQ or LLQ is not supported on the PVC configured as UBR ATM class of service because of the nature of UBR service, there is no guarantee that any traffic will get through, the actual traffic rate can be anything.

Some documentation mention that this is not supported, here is one for 12.4T train:

"CBWFQ is supported on variable bit rate (VBR) and available bit rate (ABR) ATM connections. It is not supported on unspecified bit rate (UBR) connections."

http://www.cisco.com/en/US/docs/ios/qos/configuration/guide/congstion_mgmt_oview_ps6441_TSD_Products_Configuration_Guide_Chapter.html#wp1001237

Regards,

Raphael