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New Contributor
Posts: 3
Registered: ‎10-04-2007

ISL Silkworm3900 to existing 48K Brocade Fabric

I currently have two 48k switchs Fabric and need to ISL a 3900 swt to the 48k Fabric.  Does it matter which 48k swt is used to ISL the 3900 (Principal or Subordinate)?  Also, is it possible to force the 3900 to make it a Subordinate prior to performing the ISL?

Thanks!

Occasional Contributor
Posts: 9
Registered: ‎09-02-2010

Re: ISL Silkworm3900 to existing 48K Brocade Fabric

For Brocade if there are two switches online and connected via
ISL, the switch with the lowest WWN number become principle.

New Contributor
Posts: 3
Registered: ‎10-04-2007

Re: ISL Silkworm3900 to existing 48K Brocade Fabric

Since my 48k switches are already ISL'ed together, do i need to worry about the 3900 becoming a Principle switch or will it automatically show up as a Sub when ISL'ed?  Also, does it matter which 48k swt i use to connect the 3900?  Thanks..

Occasional Contributor
Posts: 9
Registered: ‎09-02-2010

Re: ISL Silkworm3900 to existing 48K Brocade Fabric

Again, the switch the lowest WWN will will become the "Principal". So if the 3900 has a lower WWN ( see switchshow) then it will become the principal. I don't believe there is an issue with that becuase it will all be one fabric anyway.

As long as the Domain ID's are unique it won't matter which switch you ISL to becuase the switch role is not configurable on Brocade.

I would also have a look at fabricprincipal command, becuase there is a way to force the Principal if you want the core switch to be the principal.

Super Contributor
Posts: 635
Registered: ‎04-12-2010

Re: ISL Silkworm3900 to existing 48K Brocade Fabric

In newer FOS code you can find the command

fabricprincipal --disable

to disables principal switch selection.

In older codes you can use the option "fabricprincipal -f 0"

I hope this helps.

Andreas

Contributor
Posts: 39
Registered: ‎10-26-2010

Re: ISL Silkworm3900 to existing 48K Brocade Fabric

The 3900 would only become the principal if it has the lowest WWN and all 3 switches were to come up at the same time.

Adding the single 3900 to an already-established multi-switch fabric should not result in the principal switch changing even if the 3900 was to have the lowest WWN.  But upon reboot of the fabric (say, after a power outage or something), the principal could change as everything comes up together.  Not that it really matters all that much.  The principal's job is simply to ensure domain IDs are unique and to keep the time in sync.

If you really want to have control of who is principal though, then look into the 'fabricprincipal' command as Gary suggested.  hth.

New Contributor
Posts: 3
Registered: ‎10-04-2007

Re: ISL Silkworm3900 to existing 48K Brocade Fabric

Thank you all for your help!  Sounds like there's no need to force Principle and will connect the 3900 to the Subordinate 48k since it doesn't matter and its the only 48k with available ports....Thanks again.

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