RE: Re[2]: ISL Trunking vs dot1q

From: Asbjorn Hojmark (Asbjorn@xxxxxxxxxxx)
Date: Sun Mar 04 2001 - 20:10:04 GMT-3


   
> 802.1q still only has CST, or "common spanning tree", which is
> one per network, period (not one per VLAN). ISL has the PVST,
> or "per VLAN spannint tree".

Correct.

802.1Q (capital Q because it's an approved standard) only has a
single spanning tree. However, IEEE has the 802.1s working group
(thus the lower-case s) which will bring MISTP (Multi-Instance
Spanning Tree Protocol) into the game.

MISTP will run a number of instances of STP where each instance
will calculate the tree for one or more VLANs.

A few vendors (including Cisco) have already implemented MISTP.

-A

--
Heroes: Vint Cerf & Bob Kahn, Leonard Kleinrock, Robert Metcalfe
Links : http://www.hojmark.org/networking/


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