planning Vlans!

[rayan]

I have a LAN of class A 10.x.x.0/24. I'de like to seperate two of my
departmens from the rest of my network in order to reduce traffic. I have a DHCP server and other servers that are needed for all departments. I have a layer 3 switch. If I do supnetting, how can I get the servers avialable for all vlans?

 

[TimRegester]

There are a number of solutions.

The DHCP server can serve all VLANs just turn on the UDPhelper or similar facility on your layer 3 switch.

The servers that will serve all vlans can do this via layer 3 routing, you will need to ensure that if the server is on VLAN 1 any workstations on VLAN 2 for example use IP and not netbios to connect.

You need to place your servers carefully, traffic analysis will tell you if you should place your servers in the same VLAN as the high traffic usage Workstations or if the amount of traffic from non high usage workstations is sufficiently low that you can safely allow these to route through to the servers (because the Layer 3 switch can handle the traffic) rather than trying to get a server to operate in all 3 VLANs. An email server can usually be quite happily be placed in one VLAN and users from other VLANs can route to it. File and Printg servers meanwhile
are best placed in the VLAN of the workstations they serve.

If your L3 switch can cope with the traffic you could place the common servers in an seperate server farm VLAN, this will depend on the throughput of your L3 Switch.

The in my view worst solution is to place 3 nics in a server with 3 IP addresses and connect each to a seperate VLAN, I consider this the worst solution since it makes the server work overtime doing I/o on 3 nics and can seriously stress a server, besides Windows NT/2000/XP is not ideally suited to this scenario and it could be an admin headache.

I hope this helps.

If you are using Microsoft netwroking all this leads to other configuration issues, such as name servers and DNS but these are well documented elsewhere.