X25AM Programming Manual

Glossary
X25AM Programming Manual—527201-001
Glossary-6
NAM protocol.
NAM protocol. Network Access Method protocol. Used by the X25AM process when other
NonStop communications subsystems also using the NAM protocol want to use an
X.25 network or protocol for connection.
network. Group of nodes connected by communications lines.
node. Point of connection in a network. Usually consists of a computer or other peripheral
device that provides a switching or terminating point in the network.
nonswitched line. Line configuration that provides a permanent path between two
stations. This path can be a privately owned cable or a dedicated path leased from a
common carrier. It is generally a leased line.
octal. Base-8 numbering system.
octet. Term meaning eight bits (one byte).
OSI. Open Systems Interconnection. Set of standards used for the interconnection of
heterogeneous computer systems, providing universal connectivity.
packet. Group of bits arranged in a specific format within a frame, transmitted as a whole
on a packet-switching network. The message contains both control information (for
routing) and data.
packet level. X.25 protocol description for packet formats and transmission of data across
the link between the network and the computers, terminals, or other devices.
packet size. Number of octets of user data in a data packet.
packetizing. Procedure by which a message is broken up into packets for transmission in a
packet-switching network.
packet switching. Method for transmitting information in packets in a network.
packet-switching exchanges. Computers in a packet-switching network.
PAD. Packet assembler disassembler. Device that provides a means for assembling or
disassembling communications packets. The device serves as an interface between a
terminal or computer and a packetizing network.
PAD profile. Group of PAD parameter settings.
page. Unit of memory on an NonStop system consisting of 2048 bytes.
page. mode. See block mode.
parity bit. .Bit appended to a group of bits making an odd number of ones in the group (odd
parity) or an even number of ones in the group (even parity).