From: Asbjorn Hojmark (Asbjorn@xxxxxxxxxxx)
Date: Tue Dec 26 2000 - 19:34:57 GMT-3
> I believe you need to use a Cat 3900 with a ISL card to do TR
> ISL.
Well, it could also be a couple of C5Ks.
> The ISL card is a ethernet trunk to another switch and TR VLANs
> are encapsulated in it.
In the strictest sense, ISL isn't an *ethernet* trunk. Ethernet
trunking is defined in 802.1Q and while ISL can *carry* ethernet
VLANs, ISL framing can hardly be called ethernet, and ISL carry-
ing token-ring can in no way be called ethernet.
I know Cisco marketing would argue otherwise, but in my mind, ISL
isn't ethernet any more than, say, ATM LANE.
> The Cat 3920 doesn't have a ISL uplink.
Huh? What about WS-C3900-2ISL?
Did you mean to say, there's no such thing as a 3920-uplink that
takes token-ring VLANs and bridges to a trunk with ethernet fra-
ming? (Sort of like the Olicom 8660 which also does 802.1Q).
No, the thing that comes closest is a 5000-series switch with a
token-ring blade and a route-switch module. (Not really economi-
cally an attractive alternative).
> And I don't think there exists native TR ISL
I agree. There's ISL carrying ethernet and ISL carrying token-
ring, but no such thing as native ethernet ISL og native token-
ring ISL.
> Certainly can stack 3920 switches using a special cable but
> no mention of TR ISL.
Stacking on the 3920 is ISL (carrying token-ring).
-A
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