I am looking to have information about port to port latency on cisco
1- Port to Port latency of port on same port group and cross bar
2 - What is the subcription ratio.
Basically I am in process of selecting between Brocade 4800 vs MDS.
There are other Cisco whitepapers on switch architecture at,
One on more detail of the LC's and crossbars at,
Any of the resellers, pick one, has access to Cisco Technical Marketing to address your questions directly with regards to Brocade vs Cisco
Check out performance testing by Miercom, it has latency range/distribution based on frame size.
"The MDS 9509 showed excellent performance regardless of frame size. It achieved near line
rate with small frames (98.67%) and full line rate with large frames, both with 100% intended
load. Regardless of the load, the minimum latency for both frame sizes was very consistent. For
small frames, it varied from 7.2 to 52.9 ?s under 100% intended load. For large frames, the
latency ranged from 19.7 to 218.9 ?s under 100% intended load. Furthermore, the MDS 9509
was able to sustain traffic at a much higher throughput rate for minimum- and maximum-sized frames while maintaining a more consistent latency then other switches tested."