Since February, however, the Arboretum LAN has been connected to the University backbone, and from there to the Internet, via a US West 56 kbps frame-relay connection. But because frame relay shares infrastructure among multiple users, it is a cost-effective way to connect remote LANs to the campus backbone. From that point on, the service provider network is a mesh of physical switches and fiber lines that statistically multiplexes data from multiple PVCs over the same infrastructure, making better use of resources and lowering costs to the customer. Frame Relay networks deliberately overbook resources. Computer data applications require lots of bandwidth for very brief intervals, leaving dedicated lines idle much of the time.
Frame relay switches multiplex data on shared lines asynchronously .
Frame relay switches transfer data packets just as quickly as they can, without correcting any corrupted data, checking order sequence, or waiting for acknowledgment of packet delivery. In this they are an outgrowth of the demonstrably inherent reliability of digital transmission over glass fiber, on the one hand, and the general recognition, on the other, that since end points must handle data integrity, sequencing, and retransmission anyway, intermediate switching gear can achieve significantly better performance at much lower cost by giving up these functions. Our counterparts in Duluth have had several frame-relay connections in place for some time. These sites connect to UMD via frame relay and then over leased lines to the rest of the University system and the Internet. We expect to use frame relay to connect ten to twenty Access Minnesota sites from all over the state into our network by the end of June.