I am sure you can.. Just ensure the Domain ID's are different. My shop runs with 21 switches in Fabic with different Frimwares and we are in a painful process to upgrade them .

Navin.

Painful ? Why is it painful ? With the present firmwares you can upgrade them without any fibre channel downtime. Only the management interface is affected when the cluster software within a Brocade reloads, but host connectivity remains unaffected.
[ We are running something like 80 switches with firmware releases 2.6.2a up to 5.2.1 and all is running just fine ]

We are running 2800's on fw level 2.6.2a and as far as I know, this is the latest level for that switch.
The 3800's are running a mix of fw levels up to 5.0.3. Our 3900's are also running 5.0.3. Our newer 4100 en 5k switches are running fw's up to 5.2.1 already.

In the EMC upgrade manual it says that if you're upgrading from firmware levels prior to 4.2.2, you must first upgrade to 4.2.2 and after that has been done, upgrade to higher and newer version. As far as I can remember (but I can't verify that this quickly) versions below 4.2.2 require a reboot and after 4.2.2 everything is upgrade while staying online. Since most of your customers aren't running failover software, I would be very careful anyway with any upgrades you're planning.

the upgrades I did so far were all on DS220B, 4100B and 5000B's and they all were upgrades without any fibre channel downtime. Those switches have 2 partitions running each it's own firmware and while one is being upgraded or rebooted, the other partition keeps the switch running.

I didnt knew if we can upgrade a firmware without rebooting a switch.? It regarding what firmware levels and switch numbers.. pls pass on if you have any more info.

Regarding my pain: we have brocade 2800, 3800,3900 and 12k core switches with firmware verions 2.6.0 onwards... Every firmware upgrade means a switch reboot and since most of the servers are without Powerpath we need to verify the servers availability will not be affected during the firmware upgrade, ensuring Full system backup's and getting the business approvals from some stubborn Business owners..
Technicaly upgrading the firmware is not a pain.. it's all the other stuff involved.

Oh good thanks for that explanation; so i can upgrade above 4.2.2 without any downtime. (I will anyways confirm it before doing).
We are planning to replace all edge and core switches with 48k's. We are still on the drawring board with this solution.
Will come back with lots of questions soon on this .
Thanks,
Navin.

Domain ID are different, If we have 2 switches, Switch-1 domain id is 1 and Switch-2 domain id is 3, can we use this combination to ISL.

Maybe we should start a separate topic on this and repeat the stories told here ?
And besides that I'm not sure with what version exactly the non disriptive upgrade came into place. When I have a few minutes time, I'll try to check this with EMC for you.

yess you can..