Zoning limitation is the size of Zone DB. You can use "cfgsize" command to see the actual size of DB and free space. Additional license not requered.  With ISLs you can connect fc-switches to one fabric and configure zonning on one switch, zone config be moved to others. If use trunking license and connect switches more than one ISL you can increase a bandwith (for example, two 4 Gbit/sec ISLs between switches can give 8 Gbit/sec connection (trunk) between switches)."Enabling multiple physical ports form a trunking group where the traffic is distributed dynamically and in order at the frame level, thus achieving greater performance with fewer inter-switch links." : FOS AdminGuide 6.3.
Hi Expert,   SETUP:   Kernel:     2.6.14.2   Fabric OS:  v6.2.1b BootProm:   4.6.6 Model: Brocade CONTRX - 4100 - 32 port   Anyone  please  answer   my below  queries      Is there any limitation to create zoning? Presently we have 40 zone. Is there any license required for more zone?    How ISL work and what are the advantages?   best regards, Muneer.
Zoning