Integrating the portable APPN protocol stack into a multiprotocol router

Advanced Peer-to-Peer Networking (APPN), including High Performance Routing (HPR) and Dependent LU Requester (DLUR), has been implemented as a portable code base. This paper provides an overview of APPN functionality, and then examines the five interfaces that must be met to integrate the portable APPN code into a multiprotocol router: operating system, configuration, data link control (DLC), HPR's network control layer (NCL), and network management. Operating system portability is achieved through a system services interface layer. Node configuration is managed by a layer that interfaces between platform-specific configuration mechanisms and a verb-based API at the top of the portable stack. The DLC and NCL interfaces are supported by lagers at the bottom of the portable APPN stack; the DLC layer provides a common interface to system-dependent data link control implementations for intermediate session routing, while NCL serves a similar purpose, encompassing priority-based forwarding, for High Performance Routing. Network management interfaces are available for SNA management services and SNMP. Each of interfaces to the portable APPN protocol stack and the associated design issues are described in the context of a multiprotocol router implementation.