ABSTRACT
The data link/network layer provides the low-level services for routing of messages over the LAN, for controlling the flow of data over the LAN. It provides for addressing capabilities and for synchronization and error-handling capabilities. The function of this layer is to provide services to access other LANs via bridges and gateways. Centralized adaptive routing utilizes a central routing control center that takes in systems status information and computes new routes for each node. Flow control and congestion control are needed in networks where excessive message loading causes loss of messages and degraded performance. The Global Unique Identifiers reside in a "catalog" that defines the actual parameters necessary to acquire and access an object. Binding protocols, or levels, are used to define in a logical and physical way, how the namings extend down into physical realizations in a hierarchical fashion. With the proliferation of personal computers and intelligent workstations, an attendant explosion in the number of computer networks has occurred.
