100TX/100FX media converters and CISCO ISL

[simonepezzano]

Hi all!

I'm looking for some info about 100TX/100FX media converters and CISCO ISL.

Cisco ISL supports ethernet, fddi and token ring trunking, so the MTU can be up to 18k instead of 15xx bytes (802.1Q).

Teorically, media converters are layer 1 devices, so there shouldn't be any relation with the layer 2 protocol used and should work also with Cisco ISL.

So here's the questions:

1. has anyone ever tried media converters with Cisco ISL setups, where the token ring frame switching works at least at 4096 bytes?

2. Any reference site?

3. if any, available products working with this mess?

Thanks a lot, you always are very helpful

[owillins]

As far as I know, some fiber transceivers chop off frames bigger than 1518 bytes and hence drop token ring frames encapsulated in ISL. Please share any information that you find on converters that work with 4096 bytes.