Glossary
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UNSHIELDED TWISTED PAIR (UTP)—A cable used in 10Base-T wiring that
consists of at least two twisted pairs of 22 to 26 AWG wire. The pairs should have at least
3 twists per foot and have an impedance of 100 W. Level 3, Level 4 and Level 5 UTP
cables fit these criteria.
USER-TO-NETWORK INTERFACE (UNI)—The interface between an end device
and a public or private ATM switch.
VIRTUAL CIRCUIT (VC)—A connection between end users that has defined end
points and route but does not have bandwidth dedicated to it. Bandwidth is allocated on
demand by the network as users have traffic to transmit.
VIRTUAL CHANNEL CONNECTION (VCC)—Virtual channels in two or more
sequential physical circuits can be concatenated to create an end-to-end connection
called a VCC. A VCC is a specific instance of a SVC or PVC. A VCC may traverse one
end-to-end VPC or several sequential VPCs.
VIRTUAL CIRCUIT IDENTIFIER (VCI)—Field in an ATM cell that maps the cell’s
route through the ATM network.
VIRTUAL LAN (VLAN)—A user-configured logical workgroup or collection of
Ethernet addresses, as opposed to a physical LAN defined entirely by wiring.
VIRTUAL PATH IDENTIFIER (VPI)—Field in an ATM cell that maps the cell’s
route through the ATM network.
