Cisco ME3400E Metro aggragation switch QoS

[COLIN]

Hi, can anyone advise on the ME3400E switches handling of incoming packets that are DSCP marked, using CBWFQ, as to if by default the marking is trusted or if  reclassification and re-marking is needed. I have read several blogs that suggest both methods of packet handling with regard to dscp i.e QoS trusted by default or that all marking is removed and therefore you need to set the dscp/cs values again. Using the command set dscp dscp within the class is equivalent  to 'ms qos trust dscp'

[acampbell · Accepted solution]

Hi Colin,

ME3400E uses the cisco MQC method of providing QOS.
IE// You have to use class-maps & policicies along with your policers etc

http://www.cisco.com/c/en/us/td/docs/switches/metro/me3400e/software/release/12-2_60_ez/configuration/guide/ME3400e_scg/swqos.html

Default QoS Configuration

 There are no policy maps, class maps, table maps, or policers configured. At the egress port, all traffic goes through a single default queue that is given the full operational port bandwidth. The default size of the default queue is 160 (256-byte) packets.

The packets are not modified (the CoS, DEI, DSCP, and IP precedence values in the packet are not changed). Traffic is switched in pass-through mode without any rewrites and classified as best effort without any policing.

There are some examples of QOS config in the link I have provided

Regards
Alex

[COLIN]

Many thanks Alex for your response, apologies for my late reply.

My further reading and the a TAC document I now have on the subject confirms the behaviour and am now looking at translation of our mls qos parameters to MQC.