From: Chuck Church (cchurch@xxxxxxxxxxxx)
Date: Fri Mar 02 2001 - 00:33:58 GMT-3
Seeing how an IP only network can have about 500 devices per VLAN, that's
about a half million devices at the VLAN maximum. Worst case would be 150
VLANs with all Appletalk supporting 30,000 devices. That would be a real
full building/campus. I'd say it's possible, but not real likely.
Hopefully, by the time you've got 150 subnets, you're already thinking about
summarization. By the way, we've got a 2948G switch in our office.
Supporting about 50 users and anywhere from 2 to (at times) 8 etherchanneled
servers, it laughs at everything we've thrown at it. Simultaneous ghost
builds, transfers, everything, and 'sh system' only shows our peak usage as
1%. Amazing...
Chuck
-----Original Message-----
From: Chuck Larrieu [mailto:chuck@cl.cncdsl.com]
Sent: Thursday, March 01, 2001 8:20 PM
To: Alan Basinger; Asbjorn Hojmark; 'Blade Of Darkness'
Cc: ccielab@groupstudy.com
Subject: RE: ISL Trunking vs dot1q
Don't know, but according to the Cisco product book the 2948G-L3 supports
both ISL and 802.1Q
nice looking box. Seems to have a lot of very nice features. Might be an
issue with the 22 gig backplane, although I am one of those who believes
that much of the concern with backplane capacity is misplaced. Theoretical
capacity versus expected real world capacity are two different things.
Speaking of vlans, most of Cisco's devices currently support 1024 vlans.
Someone here said Cisco is coming out with boxes capable of supporting 4096
vlans.
Anyone know of any real world situations where more than 150 vlans are in
place? I don't mean Cisco Systems corporate headquarters, where they
probably have thousands of vlans in place just to prove can be done, but
real businesses using vlans for real business needs. I have a potential
customer who claims to have 150 vlans operational. I have spoken to people
with extensive experience in the field who claim they have never seen more
than a dozen of so vlans in the real world.
Chuck
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Alan
Basinger
Sent: Thursday, March 01, 2001 4:10 PM
To: Asbjorn Hojmark; 'Blade Of Darkness'
Cc: ccielab@groupstudy.com
Subject: RE: ISL Trunking vs dot1q
Would the 2948L3 be built on the granite chipset?
Alan
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Asbjorn Hojmark
Sent: Thursday, March 01, 2001 5:16 PM
To: 'Blade Of Darkness'
Cc: ccielab@groupstudy.com
Subject: RE: ISL Trunking vs dot1q
> Has anyone experience the pros and cons of isl vs dot1q?
> I am asking about performance-wise and all equipments are
> ciscos.
I tend to use dot1q, because it's the standard. Also, dot1q is
supported by all new switches while ISL is only supported by
some.
> Why would one chose to use isl instead of dot1q?
If you need to transport token-ring in a trunk, ISL is the only
way to go. Some older boxes (also from other manufacturers) don't
support dot1q.
> And can the cisco WS2948G (only G) use isl?
No. All the Granite-based switches support only dot1q.
-A
-- Heroes: Vint Cerf & Bob Kahn, Leonard Kleinrock, Robert Metcalfe Links : http://www.hojmark.org/networking/
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