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New Member

Lan Design Help needed. 500 servers and 5 switches


I need some suggestions on setting up a new lan for a customer.

They have approximately 400 systems that all need to be connected to a gigabit backbone. We have 5+ 5000 series catalyst switches to use that are populated with 24 port 10/100 modules and supervisor III w/ netflow card engines.

The systems are broken up into 2 subnets. 96.x and 104.x

I was thinking the best way is to setup all of this is:

-Setup 96.x in one vlan, and 104.x in another vlan.

-Dedicate 1 switch as the "core" switch which will connect to the core router with a gigabit connection.

-Core switch will have 200mbs (2 x 100) (effectively 400mbs with full duplex) etherchannels to each of the 4 switches.

-Setup VTP Trunking between the switches and the core switch.

-Setup VTP Trunking between core switch and Router for inter-vlan routing. (Unless I can get a layer 3 core switch to do this instead?)

-Also if possible to setup some QOS for priortizing ssh/telnet/icmp packets.

If I setup VTP, would that allow mac address information from each switch pass through each switch without going to the router? ie, will server on switch #1, be able to get to a server on #4 by only going thru the core switch?

Thinking it would look something like this:



Core Switch

* * * *


S = Switch1-4

* = etherchannels

| = gigabit link

Please post any suggestions/comments. Thank you!


  • Other Network Infrastructure Subjects
New Member

Re: Lan Design Help needed. 500 servers and 5 switches <=== read this to get a better understanding of VTP. <=== this will give you a better idea on how inter-vlan routing works.

You can also use a RSM (RSFC) instead of an external router, that is, if you can find one. They are EOS and EOL, I believe...

Gigabit to a router is nice, but may not be entirely necessary. 100Mbps is usually enough (and less expensive). Since the SupIII with NFFC can to MLS (L3 switching), the router will have to deal with less traffic on the whole! <=== MLS info...The switch WILL require the external router or RSM, for sure!

New Member

Re: Lan Design Help needed. 500 servers and 5 switches

Thanks for the links. I will begin my reading :)

The main reason for gigabit to the router is the router has a 500mbs link from their provider and needs to be passed down to the switches. So gigabit fiber between the router and the core switch.

Make the core switch a vtp server and with a RSM it would be able to do the inter-vlan routing and take the load off of the router as you said.

Definately have to read up on the MLS.

Also, this customer is using the connection as a datacenter putting hosted servers up for people.

Besides assigning vlans to a specific port, is it posible to have the port become part of a vlan based on the server ip that is plugged into that port?



New Member

Re: Lan Design Help needed. 500 servers and 5 switches

You can assign a host to a vlan based on MAC address - see VMPS. Not exactly what you want.