configuring ip routing on a lan subinterface is only allowed if that subinterface is already configured as part of an
Posted on 2003-03-30
I have a Cisco 1720 router that I am trying to configure for ISL VLAN routing. I have a Cisco 3524xl switch that has been configured for the port of the router in switchport mode trunk.
However when I try to use a sub-interface on the 1 fast ethernet 0 port and enable isl encapsulation it gives me the error in the subject line.
it will let me add a secondary address but that does not do much good on creating sub interfaces to simulate two.
This is ios 12.13b ip\fw\ids plus 3des