AF_DECnet Address Families

The AF_DECnet Address families include:

DECnet Phase IV Node Addresses

DECnet Phase IV node addresses are hierarchical, indicating the routing area and the node number within that area. The binary format of the address is a 16-bit unsigned integer. The high-order 6 bits indicate the area, the low-order 10 bits are the node number within the area.

The ASCII format of the address is area.number with area in the range 1–63, and number in the range 1–1023.

For example: A DECnet node address in area 5, number 7 is represented as shown in the following table.

DECnet Extended Addressing

DECnet extended addressing allows the DECnet NSP transport to be run over the OSI-routing layer. Sockets opened through AF_DECnet assumes that addresses of 3 to 20 bytes in length are OSI-style addresses.

DECnet Objects

DECnet client tasks specify the server task that they want to communicate with by using network object number and task names. The DECnet object number is an 8-bit unsigned value. Object numbers in the range 1–127 are reserved as generic objects for digital use. Numbers 1–128 are available for user-written generic objects.

If the object number is zero, then the network connect is done to a specific server task name. Task names are 1–16-byte ASCII strings.