Ip subnet and vlan

hello, plz i am designin a vlan network, which have two router on each site ...one fast ethernet and one serial interface on the router.
im using hierarchical model to design the network. this ip address has been allocated 192.168.0.0 and i have all these hosts on each site.
site 1...... site 2
human resources....150 hosts pillar branch...........83hosts
sales.......................100 warehouse..........68
marketing............92 admin.................64
accounts...............58 newyor.................36


my question is im struggling with ip addresses range of each hosts...can anybody help me out with ip range and vslm addressing

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Do you have to use 192.168.0.0 or is that just what you've decided to use? The 10.0.0.0 space would give you more flexibility!

Basically, you need to do two things:

Split your address space into two.
The two sites need their own part of the address space.

With the 192.168.0.0 space that's probably easiest to do using the 17th bit. One site will have addresses with that bit as 1, the other as 0. That's easiest to show in binary:

Site one: 11000000.1010100.00000000.00000000 (192.168.0.0)
Site two: 11000000.1010100.10000000.00000000 (192.168.128.0)

So site one can then use IP addresses from 192.168.1.1 to 192.168.127.254
Site two can use 192.168.128.1 to 192.168.255.254.

Split the site subnet into smaller subnets for each group
I'd then recommend that you use the rest of the third octet for each of the groups. So for example:

Site 1
human resources: 192.168.1.0 (IPs 192.168.1.1 to 192.168.1.254)
sales: 192.168.2.0 (IPs 192.168.2.1 to 192.168.2.254)
marketing: 192.168.3.0 (IPs 192.168.3.1 to 192.168.3.254)
accounts: 192.168.4.0 (IPs 192.168.2.1 to 192.168.4.254)

Keep 192.168.0.0 (192.168.0.1 to 192.168.0.254) for network systems

Site 2
pillar branch: 192.168.129.0 (IPs 192.168.129.1 to 192.168.129.254)
warehouse: 192.168.130.0 (IPs 192.168.130.1 to 192.168.130.254)
admin: 192.168.131.0 (IPs 192.168.131.1 to 192.168.131.254)
newyor: 192.168.132.0 (IPs 192.168.132.1 to 192.168.132.254)

Keep 192.168.128.0 (192.168.128.1 to 192.168.128.254) for network systems

What mask you use depends mainly on how much you want to separate the segments. If you want to isolate each group and connect via the router (using VLANs too if you wish) then use a mask of 255.255.255.0. In this case your router (or VLAN switches) will need IP addresses on each subnet.

For routing between the two site routers use a 255.255.128.0 mask. So for the site 1 router, it will send packets to site two at 192.168.128.0/255.255.128.0.

This does get complicated if you want to add a third site and is therefore not particularly scalable. You'd probably redesign slightly and use two, three, or four bits to identify main networks.

A simpler and more scalable solution
In the 10.0.0.0 space you can use the second octet to split the main networks. Then you could have site one using 10.1.0.0, and site two 10.2.0.0. Adding a third site is then easy: use 10.3.0.0.

Then the third octet can be used to split the groups. That's much simpler to manage because you can split things using whole octets rather than individual bits. So site 1 group 1 uses 10.1.1.0, and site 2 group 4 uses 10.2.4.0.

With the 10.0.0.0 address space, you'd use a 255.255.0.0 mask for routing between networks, and can use a 255.255.255.0 mask within each site to split groups.