05-09-2012 09:20 AM
as you didn't provide exact models, here are possible cases:
FC8-48 blade in a 8G DCX director: all ports are capable of running 8G; however the backplane connection is 32x8G thus the confguration would be 1.5:1 oversubscribed (48:32) in the worst case scenario. But, because Brocade ASICs utilise "local switching" (switching packets within ASIC ports on a blade wherever possible) the stated theoretical oversubscription rate is not an issue in most setups.
FC8-48 blade in a 16G DCX 8510 director: not supported.
For 16G directors there is another blade called FC8-48E which can run all ports on 8G but has 16G connections to the backplane.
FC8-48E is not supported in 8G DCX directors.
Hope this helps,