User manual

Wide Bank 28 DS3 - Release 2.4 July 2004 Glossary-11
Glossary
Packet Switching An efficient method for breaking down and handling high-volume traffic in a network. A
transmission technique that segments and routes information into discrete units. Packet
switching allows for efficient sharing of network resources as packets from different
sources can all be sent over the same channel in the same bit stream.
Parity Check An error-checking scheme which examines the number of transmitted bits in a block which
hold the value one. For even parity, an overhead parity bit is set to either one or zero to
make the total number of transmitted ONES an even number. For odd parity, the parity bit
is set to make the total number of ONES transmitted an odd number.
Path A logical connection between two points in a network, which may follow many physical
paths.
Payload The portion of the digital signal, excluding overhead, that is available to carry voice and
data services to the subscriber.
Ping An Internet application used to test IP-level connectivity. Ping sends packets toward an
Internet device address and then measures the round-trip delay time required for the device
to reply.
Point of Presence POP. A point in the network where inter-exchange carrier facilities like DS3 or OC-N meet
with access facilities managed by telephone companies or other service providers.
Poll An individual control message from a central controller to an individual station on a
multipoint network inviting that station to send.
Remote Alarm
Indication
RAI. A code sent upstream in a DSn network as a notification that a failure condition has
been declared downstream. (RAI signals were previously referred to as Yellow signals.)
Remote Defect
Indication
RDI. A signal returned to the transmitting Terminating Equipment upon detecting a Loss
of Signal, Loss of Frame, or AIS defect. RDI was previously known as FERF.
Remote Error
Indication
REI. An indication returned to a transmitting node (source) that an errored block has been
detected at the receiving node (sink). This indication was formerly known as Far End Block
Error (FEBE).
Remote Failure
Indication
RFI. A failure is a defect that persists beyond the maximum time allocated to the
transmission system protection mechanisms. When this situation occurs, an RFI is sent to
the far end and will initiate a protection switch if this function has been enabled.
Severely Errored
Framing Seconds
A second with one or more Out of Frame defects OR a detected incoming AIS.
Simple Network
Management
Protocol
SNMP. An application layer providing connection-less protocol and running over UDP
(User Datagram Protocol), that functions as TCP’s stack network management protocol
between a management station and a SNMP agent resident in a managed device. For
managing TCP/IP-based networks, SNMP is the de facto standard. SNMP is designed to
implement an automated network-management system for controlling and performance