[c-nsp] 7600 and LLQ error

[Anton Kapela]

> service-policy output xxx
> 
> priority command is not supported in output direction for 
> this interface Configuration failed!
> 
>  
> 
> can somebody help me?

LLQ (as well as the majority of the modular qos commands) isn't supported in this manner on ws-x65xx/67xx/etc gigabit line cards. You need OSM, Flexwan, or SIP-based interfaces. That is to say, if you expect the PFC to control/"do" any QoS for you, you'll not be able to use these MQC-based features. Now, much of the MQC commands would actually work if somehow the switching path were through the MSFC, and in some cases certain features in the class-map might actually punt the packet up (to the MSFC). One such item would be extended 48-bit ACL's, where the user is using the arbitrary pattern/offset match features. 

That is to say, "half" of the ACL (the mac address + mask) would be matched by the PFC and then punted to the MSFC for further inspection (to match/etc the bytes at whatever offset the user specified). Once there, the MQC commands would do what you expect. 

However, this comes at a huge cost given the MSFC simply isn't intended to be in the forwarding path; you'd be walking on eggshells to try.

The way you'd want to do this is to use the priority queue support of the ethernet interface itself by setting the CoS value on packets matched in your class map and then by grouping these CoS values to queues. A few examples:

-assuming you already have packets (frames, etc) marked with the appropriate CoS, map them to one of the WRR (weighted round-robin) queues with the following:

http://www.cisco.com/en/US/products/hw/switches/ps708/products_white_paper0900aecd80233956.shtml

-Page 11 (..graphically, even) shows the concept of matching DSCP to set CoS, and then how this maps to WRR queues. Find your line cards, find the queue types, and adapt these examples to fit your use-case. 

http://www.cisco.com/application/pdf/en/us/guest/netsol/ns657/c654/cdccont_0900aecd804c7087.pdf#search=%22wred%20on%206748%22


-Tk