EXTREMELY new Brocade FC guy here, so please bear with me.
I have a new 6505 that I want to ISL an existing IBM/Brocade 5470 switch which is in an IBM BladeChassis. It appears that the newest FOS that I can run on the 5470 is 6.4.3 while the 6505's are running 8.0.1 right now.
After looking at the documentation, I THINK it states that the 8.1.0 FOS supports connection to the 5470 if the 5470 is running FOS 7.3.1 or later. Is that correct?
See page 45 in this link: ftp://public.dhe.ibm.com/storage/san/fos8/v8.1.0c_ReleaseNotes_v1.0.pdf