Would a private-line net need a router?

We are building a network similar to one  you described in your April 14 column. We prefer the security of the private-line method to using frame relay to interconnect our LANs. Would a private-line network connecting three nodes with two spokes connected to a hub require us to install and configure an IP router at the hub site just to move traffic from one spoke node to the other? Or can we make the connection directly?

In a three-noded T-1 network, where one hub node is connected to two spoke nodes, you can terminate each T-1 on dual-channel CSUs with one port on each CSU feeding different ports on a router at the hub.

This way, the through requirement for connecting Spoke 1 to Spoke 2 via connections to the hub site can be achieved by interconnecting the second port on each CSU with a crossover cable (as long as your routers and CSUs provide for defining the appropriate channels for your T-1s).

Adtran and Cisco make this relatively easy. Additional spoke nodes can be added, but they require additional CSU ports and/or routing facilities.

Expandability is one of the attractions of using frame relay, or even Internet VPN networking.