Nortel BCM 3.7 Manual page 935

Type of Service
See TOS.
U
UDP
Telephony dialing plan: Networked systems that connects using a Universal Dialing Plan
(UDP) have system identification numbers and a location code that are unique to each
system. Also, the Private DN length is the same on all systems. The system identification
numbers and location codes are entered as a unique destination code that gets dialed out
with whatever extension is being dialed. See also CDP.
Data protocol: User Datagram Protocol (UDP) is a protocol that offers a limited amount
of service when messages are exchanged between computers in a network that uses IP.
UDP is an alternative to the Transmission Control Protocol (TCP) and, together with IP, is
sometimes referred to as UDP/IP.
Like the Transmission Control Protocol, UDP uses IP to actually transfer a data unit
(called a datagram) from one computer to another. Unlike TCP, however, UDP does not
provide the service of dividing a message into packets (datagrams) and reassembling it at
the other end. Specifically, UDP doesn't provide sequencing of the packets that the data
arrives in. This means that the application program that uses UDP must be able to make
sure that the entire message has arrived and is in the right order.
Network applications that want to save processing time because they have very small data
units to exchange (and therefore very little message reassembling to do) may prefer UDP
to TCP. The Trivial File Transfer Protocol (TFTP) uses UDP instead of TCP.
Universal Dialing Plan
See UDP.
universal power supply
See UPS.
universal T1 Wide Area Network
See UTWAN.
unsupervised line
A line for which disconnect supervision is disabled. If an external caller hangs up, the
system does not detect the disconnection and does not hang up its line. See disconnect
supervision.
UPS
The Universal Power Supply is a third-party piece of hardware that attaches through the
Business Communications Manager serial port to provide power backup in case of a
power failure.
Programming Operations Guide
U 935