Configuring ISL on Cat2924XL

[Bob Chahal]

I'm trying to configure an ISL Trunk on one of the ports on a CAT2924XL
running the enterprise edition software IOS (tm) C2900XL Software
(C2900XL-HS-M), Version 11.2(8)SA4, RELEASE SOFTWARE

fc1)

I configure port f0/1Switch(config-if)
#switchport mode trunkSwitch(config-if)

I then do
#switchport trunk ?
This does not present me with the encapsulation keyword

However, if I do a show int f0/1 switchport it shows

Name: Fa0/1
Switchport: Enabled
Administrative mode: trunk
Operational Mode: trunk
Administrative Trunking Encapsulation: isl
Operational Trunking Encapsulation: isl
Negotiation of Trunking: Disabled
Access Mode VLAN: 0 ((Inactive))
Trunking Native Mode VLAN: 1 (default)
Trunking VLANs Enabled: ALL
Trunking VLANs Active: 1,2
Pruning VLANs Enabled: NONE

Is ISL on by default . The config info on CCO states that this needs to be
explicitly configured.

Anyone come across this before?

[George Spahl]

Bob,
That's all you have to do. You would set the encap if you were making it a
regular access port. If you're connecting to a router that supports ISL
trunking you'll need to configure the VLAN encapsulation on the
corresponding router interface/sub-interface. Remember to set up VTP
properly. The default VTP setting on each switch is "server", but this will
get you in trouble if you leave it this way and you are using more than one
switch. The switches won't exchange VLAN information and the trunking will
work erratically or not at all.
George

Bob Chahal wrote in message
<940660215.20053.0...@news.demon.co.uk>...

[Ray Wood]

While the documentation for SA4 software indicates in several
places that 802.1Q trunking is supported, if you check the release
notes you will see that 802.1Q was not supported until SA5.

Hence, in your version of code, since ISL is the only trunking
supported, there is no need for the ENCAPSULATION command
and you are, indeed, configured correctly for ISL trunking.

Ray Wood