IP Management

For better management of your IP addresses, use Variable Length Subnet Masking (VLSM). This allows you to subnet at areas other than class boundaries. For example, if you have class B space, you wouldn't have to assign every floor or department a class C address space. You could assign them 1/2 a class C, or less depending upon their size just by changing the subnet mask on the router. That will save you "legal" IP addresses. Remember that VLANS have to communicate with other VLANS througha router or layer 3 switch so make sure your routers support VLSM. For more detail, try www.cisco.com and search on VLSM.

If you want to simplify administration of your address space, use Dynamic Host Control Protocol (DHCP) and set up a server to administrate IP address assignment. We use MetaIP and it really simplified our lives! The administrator takes an assigned subnet and creates a range of addresses available for use by that VLAN/Floor/Department and the server hands out the addresses when the end-user comes looking. We always make sure to reserve some address space in each subnet for static devices (switches, routers, servers, printers). If your users are using Windows, make sure their PC network properties are set to look for an address from a DHCP server. Hope this helps or at least gives you some ideas.
- ck

Remebre you only need Global IP address ranges where the network is visible to the Net or for access to and fromn the Internet.
You can use any non-internet routable addresses behind your firewall
ie floor 1...10.1.1.0/24 ( expandable past 254 addresses if required)
floor 2...10.2.1.0/24 etc
using the same mask means machines can be changed around with little confusion.
This keeps the numbering scheme simple and easy to follow.

Break away from what is existing and design your own planwhich is flexible