LAN/WAN interworking in the OSI environment

The rapid growing number of LAN and WAN services makes interworking between these two types of network increasingly important. This article describes the different LAN/WAN interworking scenarios, without referring to a particular type of LAN or WAN, i.e. it concentrates on OSI Layer 3 and 4. If there is a homogeneous network service, them interworking within the context of the Basic Reference Model is possible. If not, then such interworking is not possible. For the latter case, the international standardization community presents two interworking scenarios: the interworking functional unit and the distributed system gateway. The concepts of naming, addressing, routing and relaying in the OSI environment have been described in detail in part one [3] of this two part series