Hi all. I've been working on setting up bandwidth shaping on my C3560, C6500 (native), and C2950 switches, and have noticed that each switch maps DSCP/CoS values to egress queues differently. Why is this?
It seems that do apply shaping correctly across the LAN, I would need to be consistent in giving each DSCP/CoS value the same bandwidth, but this is making it difficult. I realize I could easily re-map the values to different queues, but the hardware itself has different buffer sizes per queue. So for example, the 6500 has CoS 2,3,4 mapped to Q2 w/ 20% of buffer on the linecard I'm using, the C3560 has CoS 2,3 in Q3, and 4,6,7 in Q4, with each queue getting 25% of the buffer space.
Maybe I'm making more out of this than I should, but it seems like a lot of work to remap the CoS/DSCP to queue settings, as well as the SRR/WRR buffer settings.