We have a WAN with more 40 branch offices. Our main problem is the HQ office where our class c or /24 ip we had has runout and we now need to expand. we have ip range 192.168.1.0/24. we have 20 DB servers and a DHCP Server. In small summary diagram our network is like below
The problem is how we increase the LAN segment. we are considering number of options and they all have pros and cons and I wanted to some experts views;
1. We are considering just increasing the LAN segment to a class B, but we fear that the broadcast domain will grow too big on the same segment where the application servers are sitting. We are also reluctant to change IP settings on some application servers which have misbehaved in the past when you change the IP address setting.
2. Or We would like to introduce a bigger router before the Firewall and break the LAN in different segments, but need to be sure all the LAN segments applications will work fine
3. Another option is to do VLANs since some switches are managed ones but some are not. Am also not sure this is a good option and am not too sure if VLANs are really that good and how the configuration is done. Apart frombeinga cheaper options are the VLANs better than just using routers.
My question is what are the other options available, or which of the above would best suit our scenario. Any piece of advice will be highly appreciated.