We want to connect three LANs in Sheboygan, Wis., to servers in Chicago and St. Louis. We want to use either private line or frame relay instead of the Internet. How many access lines and router ports will we need for private line vs. frame relay? Also, how would we upgrade later to connect Chicago and St. Louis in each case?

Private-line networks require point-to-point connectivity between endpoints. Connecting three sites requires two end-to-end connections.

The easiest way is to connect Sheboygan to Chicago with one line, and Sheboygan to St. Louis with another.

 Pricing might influence your hub and spoke network choices - you might have to route network traffic from Sheboygan to St. Louis through Chicago.

All three nodes can communicate with each other once two spokes are attached to a hub by configuring the hub node to relay traffic between the spoke nodes.

Upgrading a private-line network to provide an additional direct point-to-point connection requires installing another private line.

With frame relay, you can connect each site to the frame relay network, and configure virtual circuits in the frame relay network to simulate point-to-point private-line network connections. Directly connecting more frame relay sites to each other requires configuring more virtual circuits.