In an OSI network, an intermediate system (IS) is a switching component that provides certain services for the end devices. The generally applicable, network-independent term for such a network component is node; on the Internet, these are gateways or routers
. In OSI terminology, a distinction is made between an intermediate system and a relay system. The former can be any router or host
with router intelligence, the latter are pure "link elements", i.e. only routers.coupling ofCSMA/CD LANs with an X.25 WAN. In this way, subnets of different types in both the LAN and the WAN area can be connected to form a uniform global network. Intermediate systems only comprise protocol layers 1 to 3 in contrast to end systems, which have the full OSI layers 1 to 7.