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ISL & 802.1q trunk

Hi,

You know, 35xx series will be obsolete soon which will be replaced by 2950 series. 2950 does not support ISL trunking. However, my existing network is using ISL. Can ISL and 802.1q co-exist in the same network ? (i think so)

If yes, any extra thing requires to do for Vlan and STP ? (e.g. ISL and 802.1 vlan mapping, etc).

thanks.

  • Other Network Infrastructure Subjects
1 REPLY

Re: ISL & 802.1q trunk

Yes they can, 802.1Q VLANs in the range 1-1000 are automatically mapped to the corresponding ISL VLAN. 802.1Q VLAN numbers greater than 1000 must be mapped to an ISL VLAN in order to be recognized and forwarded by Cisco switches.

802.1Q supports VLAN's from 0 -4096 and ISL only up to 1000, so if you have VLAN's above 1000 on the ISL side you will have to manually map them to 802.1Q

Regards

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