L3 switches are usually used in WANs not LANs because they are soooo expensive and super fast. We only use L2 Switches wich do not work with IP only ARP in our LAN.
I would guess this might depend on budget more than anything else. At least, I know of no reason to not use L3 switches throughout your network....if you can afford it.
I'm presently in the middle of evergreening all the old cisco junk out of our network and replacing it with L3 switches. Which granted aren't cheap at $5,000.00 each.
Out of the 15 closets in our main center, I have 4 closets left to replace but those will have to be put on hold for a little while due to budgetary constraints thanks to the economy.
I would like to connect this vlan to an IP subnet ie: 10.20.30.48/28
do you by chance know the command to accomplish that on a cisco 3750 switch?
You're still not getting it. You don't "connect" a subnet to a VLAN. At least, not in the sense you're thinking.
Let's say I have a switch with 4 VLAN's configured on it. I have 4 blocks of 12 ports set to, one block to each VLAN:
VLAN 1 - Ports 1-12
VLAN 2 - Ports 13 -24
VLAN 3 - Ports 25 - 36
VLAN 4 - Ports 37 - 48
Now, I have two computers configured with the following IP addresses:
PC1 = 192.168.0.1
PC2 = 192.168.0.2
I plug them in to the first bank (VLAN 1) and start a continuous ping between them.
I can then move their plugs into any ports in the VLAN 2 bank and they will continue pinging.
I can then move their plugs into any ports in the VLAN 3 bank and they will continue pinging....and so on to bank 4
If I plug one into the VLAN 1 bank and the other into the VLAN 2 bank, they stop communicating because they're now plugged into ports that are configured for different VLAN's.