question about vlan.ip range addresses

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 172.16.0.0 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

Do you want to have 2 vlans, one for each site? or do you want 8 vlans one for each branch office?

Since you have 2 routers then the first option is probably what you need. However, you can still have 8 vlans if your switches support vlans/trunks, and your routers support sub-interfaces (i.e 802.1q or ISL).

yeah u right, my router support subinterfaces .......so do u think i should go with 8vlan cos my switches support vlan/trunks.................solo ? and also i have 650 hosts

i have two cisco router, do u think ospf or ripv2 can be configured...i dont need to used other protocols, such as eigrp or igp.i was given these two protocol to choose. i did a research on it ......but couldnt get enough informations.

i know that ripv2 can be used in cisco router environment, what about ospf

so do u think i should go with 8vlan cos my switches support vlan/trunks.................solo ?

Generally speaking, the more vlans you have, the more security, department isolation and relative performance gain you get. For example, layer 2 broadscasts would be limited to each department PCs which frees more bandwidth on other department switch ports. Security, in the sense that hackers who try to sniff your switch would be limited to sniffing only the vlan/departments that they are physically connected to, not the whole site.

On the other hand having more vlans can slightly increases the over head on administrators. Also, moving allot of PCs between departments means that their IP configs will have to be changed (unless you use DHCP). On your case, I think I'd go for the 8 vlans plan.

If you need to read about subneting, then here is a good start: www.firewall.cx/ip-subnetting-intro.php . You could skip the introduction if you want.

i know that ripv2 can be used in cisco router environment, what about ospf

OSPF can be used on Cisco routers. It's also supported on many other vendor routers. So if you happen to get new routers say from "Foundry Networks" or 3Com you won't get stuck. OSPF is also very scalable, i.e it's designed to work on large to very large networks. Although RIPv2 would be A little bit easier to configure and manage. I think OSPF is the way to go for large networks like yours.

There is much more to OSPF and RIPv2 than what I've mentioned.