Cisco BPX 8620 Installation And Configuration Manual page 587

time division multiplexing.
TDM
The process of combining several communication channels by dividing a channel into time increments
and assigning each channel to a timeslot.
See TDM.
time division
multiplexing
A field in certain FastPacket formats that indicates the amount of time the packet has spent waiting in
timestamp
queues during the transmission between its source and destination nodes. Used to control the delay
experienced by the packet.
An upper bound on the time between RM cells for an active source, i.e., RM cell must be sent at least
Trm
once every Trm msec.
See TBE.
transient buffer
exposure
A physical link between two nodes. The trunk may be one that supports 24-byte FastPackets (packet
trunk
trunk), or one that supports 53 byte ATM cells (cell trunk.)
A set of signaling and information bits that indicate a DS1 line failure.
trunk conditioning
The buffers in packet line cards (NTC, TXR) where the various FastPackets are queued up for
trunk queues
transmission over the packet line(s). The buffers attempt to prioritize each packet so it experiences
minimum delay.
U
µ-law
An analog to digital encoding scheme used to convert voice samples to an 8-bit data word used in
D3/D4 T1 multiplex equipment.
unspecified bit rate.
UBR
QoS class defined by the ATM Forum for ATM networks. UBR allows any amount of data up to a
specified maximum to be sent across the network, but there are no guarantees in terms of cell loss rate
and delay.
user-to-network interface.
UNI
The user to network interface, used for ATM connection to CPE. Compare with NNI. The protocol at
a frame relay port that passes information between the network and the user device attached to the
port.
See USART.
universal
synchronous/
asynchronous
receiver transmitter
See UBR.
unspecified bit rate.
usage parameter control.
UPC
A general procedure for controlling the rate of user data applied to an ATM network. There are a
number of different algorithms for performing UPC. See also GCRA.
Release 9.3.30, Part Number 78-12907-01 Rev. E0, May 2005
Cisco BPX 8600 Series Installation and Configuration
Glossary
GL-21