ISL Trunking on a 4506 switch

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Aug 31st, 2007
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I have a new 4506 with a SUP 4 engine and a WS-X4418-GB module installed. I want to trunk ISL to five 3560 switches through the GBIC fiber ports on the 4418 module. I can only get the 4506 configured for ISL on the first two ports of the 4418 module. Ports 3-5 will only take dot1.q trunking. Should I be able to use ISL on all ports?

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Pari Thiagasundaram Fri, 08/31/2007 - 12:14
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Nope. You cannot use ISL on all ports. On the 4418, ports 3-18 does not support ISL.

By default, the Catalyst 4500 series switch that runs Cisco IOS Software supports both ISL and 802.1Q trunking modes. The support is on all interfaces except blocking Gigabit ports on the WS-X4418-GB and WS-X4412-2GB-T modules. These ports do not support ISL and only support 802.1Q trunking. Ports 3 through 18 are blocking Gigabit ports on the WS-X4418-GB module. Ports 1 through 12 are blocking Gigabit ports on the WS-X4412-2GB-T module.

For more info, please refer to :


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