i have a few questions about a two site point to point setup.
i have two sites: site A - flat network - 172.17.x.x/18 - where the default gateway is the firewall. site B - flat network - 172.16.x.x/18 - where the default gateway is the firewall. we currently have a point to point t1 line in place, but it has been giving us problems. it is a true T1 and was installed four years ago, so the equipment is aging - hence my post... i need to replace the routers on each end and verizon has not been very helpful with pertinent information regarding the circuit.
currently the point to point routers are configured with lan addresses on the inside and are plugged into the network (ex site A - has internal address 172.17.1.1, site B has internal address 172.16.1.1) and we manage the route through our firewall (routes on either end pointing traffic from one subnet to the next through the lan router address, but are tied to the default lan interface on the gateway).
my questions are:
is this the most effective setup? i want to know if it would be better to configure the routers to be directly connected to our firewall/gateway and manage the route through the firewall interface (as opposed to the lan address and interface). if so how should the addressing scheme look?
since this is a closed circuit, do i need ip information from my isp? or can i make up arbitrary addresses on the same subnet on each end?
i have two cisco 1700 routers each with a csu/dsu card in it. i'm pretty sure i need the csu/dsu cards to capture traffic on the point to point, but what is the right way to configure the wan(csu/dsu) interface and the lan interface?