Logo: TUG TORONTO USERS GROUP for Midrange Systems
e -server magazine

November 1995: Volume 11, Number 2

Communicating with Sam

Router-Based Frame Relay

By Sam Johnston

From the questions submitted, the selected issue to be addressed in this issue is:


ur company recently completed the migration to a router based Frame Relay network. Our objective was twofold: (1.) Take advantage of the cost effective bandwidth availability of Frame Relay, and (2.) Strategically position our network for the implementation of LAN based applications as we move towards a client server environment in 1996. Based upon our new network topology, what is the most effective way to implement fault tolerance and redundancy; and support our off-site disaster recovery requirements?


f the router utilized is the IBM 2210 product, or another brand with the equivalent support features, then the router can support both the Frame Relay network connection and an ISDN terminal adapter connection via V.25 auto-dial. The router will monitor the primary interface (Frame Relay) for lost connections. If a connection is lost, the router through its WRS (WAN Restoral) configuration, will automatically establish a secondary link (ISDN) providing network fault tolerance and redundancy. Upon restoration of the primary link the router will automatically reestablish the primary link and terminate the secondary.

Utilizing ISDN as the secondary link provides the most cost effective solution for dial on demand for bandwidth restoral at 56Kbps.

Your off-site disaster recovery requirements can be supported by simply placing a router at the location. In addition, ISDN will enhance the fault tolerance and network redundancy by providing a secondary link to the off-site disaster recovery location in case a network failure occurs during a recovery process. T < G

Note: Any TUG member wishing to submit a question to Sam can e-mail or forward their typewritten material to the TUG office, or to Intesys. We would be pleased to publish your question and Sam's answer in an upcoming issue of the TUG/400 e-server magazine.