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Re: Any 1U - 2U Ethernet switches that can handle 4K VLANs?


From: sthaug () nethelp no
Date: Mon, 26 Jan 2004 18:08:43 +0100


1) Cisco ISL is much better than urgly 802.1q - first of all,  it was
designed many years before 802.1q. I am not even talking abiout those
idiots, who designed 802.1q as a _spanning tree on the trunk level_, 
which
made many configurations (which we used with ISL ain 199x years) 
impossble,
and caused vendors to extend 802.1q.

Is it April 1st? ISL changes the size of packets, does it not? So know 
you have to deal with MTU issues. What happens when I want the biggest 
MTU possible? I know it is not much a difference in size, but for some 
people, size does matter.

I am quite happy with dot1q. My gripe is with poor spanning-tree 
implementations. I don't want a single spanning-tree for every vlan on 
a trunk... I like standards, but I am happy with Rapid-PVST. Just my 
feelings about the issue. I would never deploy ISL unless I had 
something like a 1900 that did not do dot1q

Amen. At my previous employer, we got rid of ISL on almost all trunks.
I wouldn't dream of going back. The only thing I don't really like about
802.1q compared to ISL is the idea of "native" or "default" VLAN. I want
links to be either access (untagged) or trunk (*all* packets tagged).
Fortunately, reasonably new Cisco switches let me enforce that with
"vlan dot1q tag native".

Steinar Haug, Nethelp consulting, sthaug () nethelp no


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