Fibre Channel (SAN)

Posts: 36
Registered: ‎07-21-2008

Trunking 3 Brocade 300 SAN Switches

I have 3 Brocade 300 SAN Switches, cascaded together, with 8 links between each of them (Switch A and Switch B is connected to Switch C & From A to C is 8 ISLs & From B to C is 8 ISLs & There is no ISL between A and B).

I installed trunking license on all the 3 switches, and the trunk groups are automatically created.

On the Switch A = 3 trunk groups are created.

On the Switch B = 2 trunk groups are created

On the Switch C = 5 trunks (A + B)

I am not understanding why 3 trunks are created on A, and why 2 trunks are created on B. I was expecting one trunk on A and one trunk on B.

Can anyone advice me on

Why these many trunks ?

Can i delete 3 trunks on A, and create only one trunk with 8 ISLs ?  Or can i move trunk 2 and 3 to trunk 1, so making only one trunk on A.

Please advice.


Super Contributor
Posts: 425
Registered: ‎03-03-2010

Re: Trunking 3 Brocade 300 SAN Switches

Hi, it is very simple,

You have met all trunking  criteria except, may be  port group:

4 and 8 Gbps Trunking Overview
• Automatically aggregates up to 8 ISLs when the switches are connected
- Condor ASICs provide up to 32 Gbps of aggregate bandwidth
- Condor2 ASICs provide up to 64 Gbps of aggregate bandwidth
• All ports in a trunk group must operate at a common speed
- Condor ASICs support multiple 2/4 Gbps trunks between switches
- Condor2 ASICS support multiple 2/4/8 Gbps trunks between switches
Trunking port groups include: ports 0-7, 8-15, and so on
• An ISL Trunking license is required for all switches participating in trunking
- Trunking is available when the license is installed and the ports are reinitialized
• Trunking is enabled by default
- If it has been disabled, it must be re-enabled on the trunk ports using the portcfgtrunkport
CLI command
• When trunking criteria is met, the trunk forms automatically

300 Sw has 24 ports and if all the ports are active  with POD, then the port group will be 0-7, 8-15, 16-23,

so now that you have core edge topology, you should connect the ISL cable like this:

From SW A to SW C: 8 ISL  cables from port no 0-7, and here you will get a trunk of 64 Gbps if 8 Gbps SFPs are there.similarly from SW B to SW C : 8 ISL cables from SW B( port no 0-7) should be connected to SW C port no 8-15, then you will get a trunk of 64 Gbps if 8 Gbps SFPs are there.

If you have connected like this, then also you are not getting trunks, then try to create trunks by connecting the cables one after another and through CLI cmnd


for more on this cmnd see help portcfgtrunkport or command line ref guide, attached herewith.

I think this will solve ur issue.

But tell me one thing, why are you wasting your SW ports by connecting 8 ports.You can do it by 2 ports only, then keep the other ports i mean adjacent ports of port groups free, if you will get more SAN devices, connected to the SWs and it will use the ISLs, then increase the trunk.

The best practice is to do the localization like connect the storage and servers in the same SW. This will save ur ports and the utilization will be better.

Pls mark the thread, if it helped you.

NOTE: no need to delete the trunk, just add according to portgroup and adjacent port with one by one cable and trunks will be formed.

Posts: 36
Registered: ‎07-21-2008

Re: Trunking 3 Brocade 300 SAN Switches

Thanks Hemant.

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