Systems Network Architecture (SNA) has been enhanced to include features that address the topological, routing, congestion, reliability, and availability problems of networks. An important aspect of this new release of SNA is that it allows multiple active routes between network nodes. Multiple routing permits sessions between network users to use alternate routes in case of unexpected or planned route disruptions. In this paper, the multiple routing architecture of SNA is described.#R##N##R##N#An unrestricted data flow into the network can cause long delays and buffer depletion. Network congestion can be avoided by employing flow control mechanisms at both the local (node) and global (network) levels. This paper focuses on global flow control and describes the adaptive trafic-pacing "window" size algorithm that is the basis of the global flow control in SNA.
['Vijay Ahuja']
Routing and flow control in systems network architecture