FOS ISL

ISL (Inter Switch Link / Trunk) can be useful for linking a pair of old switches and new switches.

Notes: 
- Unplug the Trunk Master and the slave goes into In_Sync state.  
- Disable & re-enable, it comes back OK as the trunk master.
- Unplugging the slave has no impact on the trunk master.
- The master port is randomly chosen, and has the routing paths for the group.
  

Enabling ISL

 
# Connect to each switch as an admin user. 

# Run "portcfgtrunkport" to see if trunking is enabled.

# Disable the desired ports, 
$ portdisable 36
$ portdisable 37

# Create a trunk group having 2 interfaces, and set an index identifier. Ports are N_Port type.
$ porttrunkarea --enable 36-37 -index 37 
Trunk area 37 enabled for ports 36 and 37.

# Enter the portenable port command for each port in the TA to re-enable the desired ports, such as ports 36-37.
$ portenable 36
$ portenable 37

# Review the switch port information,
$ switchshow

# Configure monitoring if required

Disable ISL

# Backup the config, identify the trunk port
$ configupload
$ errClear
$ switchshow
$ portshow <port>

# Disable the port, then disable the trunk area,
$ portdisable <port>
$ porttrunkarea --disable <index>

# Check that server paths are all online (eg ESX host HBAs)

# Review using switchshow, portshow, errshow -r and errdump