GatesAir Intraplex NetXpress, Installation And Operation Manual

Page: 159 / 163

7—Glossary Intraplex NetXpress IP Multiplexer
Version 3.05
GatesAir, Inc. 7-5
Intraplex Products
Reference Description
MTU Maximum Transmission Unit; the limit of bytes the interface can transmit at
one time.
Multicast Communication between one sender and multiple receivers over a network; a
packet type in IP.
Netmask A sequence of 0s and 1s that screen out (mask) the network part of an IP
address; ones in the bit position are used for the network and subnet parts,
while zeros are for the host.
NIM Network Interface Module (the NetXpress multiplexer uses the NIM-1 model);
the Primary NIM installs in slot 17 of the NetXpress shelf. The Backup NIM
installs in slot 15 of the shelf. When coupled with the MIU-201 module
interface unit, the NIM-1 provides control for T1/E1 circuit emulation, LAN
and WAN traffic through 10/100 BaseT Ports, and timing control for external
stream traffic and system synchronization.
NTSC National TV Standards Committee; either the committee that developed
television standards for the U.S. or the standards themselves. These
standards are also used in Canada, Japan, South Korea and several Central
and South American countries.
OOF Out Of Frame; an OOF state starts when any two or four incorrect consecutive
frame synchronizing bits are received from the network interface and ends
when reframe occurs.
OOS Out Of Service; indicates that the NIM is not currently in service.
Packet In the NetXpress system, this is a reference to an IP protocol packet.
Early Packet - arrives too early for assembly into the jitter buffer.
Subsequently discarded. Packet sequence number determines jitter buffer
location.
Late Packet - arrives too late for assembly into the jitter buffer. Subsequently
discarded. Packet sequence number determines jitter buffer location.
Lost Packet - packet in the jitter buffer that is missing (has not arrived). Must
be played out to the TDM Bus.
Underrun Packet - discarded packet due to jitter buffer underrun condition.
Overrun Packet - discarded packet due to jitter buffer overrun condition.
Packet Bus High Speed Packet Bus (100 Mbs, full-duplex Ethernet) used for new modules
(CAMs and NIMs).
PAD Program Associated Data; associated with transmission (that is, song titles
and station call letters).
PAL Phrase Alternating Line; this color video and broadcasting standard has a
screen resolution of 625 lines, a refresh rate of 50 Hertz, and is used
primarily in western Europe and South America.
PCV Path Coding Violations; the number of code violations per second within the
path; an interval statistic.
PDU Protocol Data Unit; a frame of data transmitted over the data link layer (for
example, Ethernet and Token Ring) in a communications network. Most
people do not use this term or the term “frame” but refer to every unit of
data over a network as a “packet.”
PDV Packet Delay Variation; also called “jitter.”
Plesiochronous Almost synchronous; when sending and receiving devices of a transmission
are synchronized but yet are set to different clocks.