Routing and Flow Control in TYMNET

TYMNET uses two mechanisms for moving data: a tree structure for supervisory control of the original network and a virtual circuit approach for everything else. Each mechanism is described. The routing and flow control is contrasted with ideal routing and flow control, and also with conventional packet-switched networks. One of the mechanisms described, the virtual circuit as implemented in TYMNET, is compared to the ideal. This mechanism avoids several inefficiencies found in other packet networks. The tree structure is shown to have several problems which increase roughly with the square of the size of the network.