node type
The term node type is used in the SNA architecture. It is the classification of network facilities that support the Network Addressable Unit( NAU) protocols.
The following physical nodes are defined, referred to as physical units( PU):
PU4: Communications Controller Node Dial-up computerused to control the network,
PU2.0:Cluster Controller Node to control the terminal,
PU1:Terminal Node,
PU2.1: Low entry Networking Node, combines the features of PU2.0 and PU1 and is mostly implemented on personalcomputers( PC) with control components SNCP(System Node Control Point).