How many nodes per VLAN

Jochen Koch

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Mar 11, 2001, 9:32:46 AM3/11/01

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Hi, i learned on a Cisco course that in a pure IP environment the maximum
number of nodes should not exceed 300 and in a mixed IP/IPX environment it
should not exceed 200. A colleague told me that i can put 1000 PCs into one
VLAN. We have a mixed IP/IPX environment. How can i see how many percent of
the packages are broadcast packages especially on a Cisco 6500. With "sh int
vlan1" for example i see "0 broadcasts" and this can't be true. Thanks for
your input.

Jochen

Udo Konstantin

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Mar 11, 2001, 2:50:30 PM3/11/01

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"Jochen Koch" <co...@realcoach.de> writes:

Cisco recommends a _one-to-one_ correspondence between vlans's and ip subnets.
So there can be no more than 254 devices in one subnet.
If you need for 1000 users there is a minimum of 4 vlans recommend

Udo

Christian Kratzer

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Mar 11, 2001, 4:07:16 PM3/11/01

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Hi,

Udo Konstantin <Udo.Kon...@t-online.de> wrote:
> "Jochen Koch" <co...@realcoach.de> writes:

> Cisco recommends a _one-to-one_ correspondence between vlans's and ip subnets.
> So there can be no more than 254 devices in one subnet.

why not have a larger /22 subnet and 1022 hosts ????

> If you need for 1000 users there is a minimum of 4 vlans recommend

not with a /22 subnet

Greetings
Christian Kratzer
Toplink

--
TopLink Internet Services GmbH c...@171.2.195.in-addr.arpa
Christian Kratzer http://www.toplink.net/
Phone: +49 7032 2701-0
Fax: +49 7032 2701-19 FreeBSD spoken here!

Martin Streule

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Mar 12, 2001, 11:29:57 AM3/12/01

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Never trust any number (especially maximums...) you hear.

It depends very much on the traffic (applications) running on the network.
A plain numbers just says nothing.

With too many stations you run in a broadcast problem (and IP and IPX are
very "good" broadcasters). With a too big VLAN your PCs need their CPU to
handle broadcast traffic....

Broadcasts in Switched LAN Internetworks:
http://www.cisco.com/univercd/cc/td/doc/cisintwk/idg4/nd20e.htm

A C-Subnet is an my experience a good size and easy to understand. The PC
supporters get used to a x.x.x.1 default gateway. Misconfigurations at the
PC level are less likely this way.

It's not only about IP address range, routing and other technical stuff -
it's much about a network that's easy to understand, install (PCs!),
maintain, migrate, ...

Cheers,
Martin

co...@realcoach.de (Jochen Koch) wrote in
<98g2vi$122$00$1...@news.t-online.com>:

David Schwartz

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Mar 12, 2001, 10:21:56 PM3/12/01

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Udo Konstantin wrote:
>
> "Jochen Koch" <co...@realcoach.de> writes:
>
> Cisco recommends a _one-to-one_ correspondence between vlans's and ip subnets.
> So there can be no more than 254 devices in one subnet.
> If you need for 1000 users there is a minimum of 4 vlans recommend

This makes it awfully difficult to have hosts with IPs in more than one
subnet. And, as mentioned, /24s aren't the only subnets.

DS

Udo Fuchs

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Mar 13, 2001, 5:32:50 AM3/13/01

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On Sun, 11 Mar 2001 15:32:46 +0100, "Jochen Koch" <co...@realcoach.de>
wrote:

We use a /20 netmask in vlans and have about 1500 Clients in the
biggest VLAN. There is also a mixed IPX/IP environment with some local
Appletalk (not routed). There are different OS like UX, Novell, NT4
and W2k. Of course you must have a look on the broadcast traffic.
There is mainly Novell IPX which broadcasts RIP/SAP every 60 seconds.
But if your network is fully switched, it should be no problem for any
client.

HTH

>Jochen
>

Udo
best regards

Udo Fuchs

Jochen Koch

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Mar 13, 2001, 4:47:09 PM3/13/01

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"Udo Fuchs" <udo....@draeger.com> schrieb im Newsbeitrag
news:metrat0582er266k3...@4ax.com...

Thanks for all your suggestions. I decided to use a /22 netmask for my
workstations. It's enough to separate the workstations into physical groups
like old building, new building and production area. And i don't have to
make a VLAN for every floor, that makes me happy.

Jochen