X25AM Configuration and Management Manual

Glossary
X25AM Configuration and Management Manual—523424-004
Glossary-2
call connected packet
call connected packet. Packet that the network sends to a caller in response to receiving a
call accepted packet from a remote entity.
call redirection. Optional network facility that allows the network to pass a call to another
subscriber number.
call request packet. Packet that a caller sends to a network addressed to a remote entity to
initiate a call.
call setup. Descriptive phrase for the activities required to establish a virtual circuit,
involving call request, incoming call, call accepted, and call connected packets. Data
transmission between the caller and the remote entity can begin after the circuit is
established.
called address. Network address of a remote device or system (the entity being called).
calling address. Network address of a local device or system (the entity making the call).
call user data (CUD). Optional field, which can be included in call setup packets, such as
call request and incoming call. In standard format packets, the CUD can be specified
for a maximum of 16 bytes, depending on the protocol configured for the particular
subdevice. If the extended packet format has been configured, a CUD field of up to
128 packets can be sent, using the fast select optional facility.
channel. A path over which data and messages are sent.
character. Letter, figure, number, punctuation mark, or another symbol contained in a
message or used in a control function.
circuit. Means of two-way communications between two network entities.
clear-confirmation packet. Packet sent by the network to the caller when a call has been
disconnected in response to the caller request to disconnect.
clear-indication packet. Packet sent by the network when a call is disconnected.
clear-request packet. Packet sent by the caller to disconnect the call.
CLIP. See communications line interface processor (CLIP).
clock. In synchronous transmission, the source for timing signals.
combined station. A station configuration, connecting a point-to-point link, where each
station shares link-management responsibility. Either station can transmit to the other
without first seeking permission to do so. This is the type of configuration prescribed by
LAPB for X.25 connections. See also primary station and secondary station.
common carrier. Company that furnishes communications services to the public and is
regulated by appropriate state or federal agencies.