Cisco 678 Installation And Operation Manual page 182

Glossary
U
User Datagram Protocol. A connectionless transport protocol that runs on top of
UDP
TCP/IP's IP. UDP, like TCP, uses IP for delivery; however, unlike TCP, UDP
provides for exchange of datagrams without acknowledgments or guaranteed
delivery. Best suited for small, independent requests, such as requesting a MIB
value from an SNMP agent, in which first setting up a connection would take
more time than sending the data.
Underwriters Laboratories. A private organization that tests and certifies
UL
electrical components and devices against rigorous safety standards. A UL
Listing Mark on a product means that representative samples of the product have
been tested and evaluated to nationally recognized safety standards with regard
to fire, electric shock, and other related safety hazards.
User Network Interface signaling for ATM communications.
UNI signaling
The line rate for message or data transfer from the source machine to a
upstream rate
destination machine on the network. Also see downstream rate.
V
See Virtual Connection.
VC
A link that seems and behaves like a dedicated point-to-point line or a system that
Virtual Connection
delivers packets in sequence, as happens on an actual point-to-point network. In
(VC)
reality, the data is delivered across a network via the most appropriate route. The
sending and receiving devices do not have to be aware of the options and the route
is chosen only when a message is sent. There is no pre-arrangement, so each
virtual connection exists only for the duration of that one transmission.
Virtual Ethernet Interface.
VIP
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