Carrier Access Access Navigator, Руководство пользователя

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GlossaryGlossaryGlossaryGlossary-12 August 2003 Access Navigator - Release 1.8
Glossary
Stratum
Stratum or Stratum Level refers to the accuracy of the clock source used to synchronize
SONET communications systems. Accuracy is important in maintaining communications
across a network. During local network failures, a backup clock source is used to maintain
network timing. But when the backup clock becomes temporarily isolated because of an
equipment or line failure, the clock phase will drift slowly until the communications link
eventually falls out of synchronization. Stratum 1 is the primary SONET clock source
obtained from a Cesium beam time standard located in Paris, France. Stratum 2 is less
accurate, but can keep a network synchronized for 3 to 5 days. Stratum 3 and Stratum 4 are
each less accurate (and less expensive) and can provide backups for shorter time periods.
Symmetrical
Digital
Subscriber Line
SDSL. A service providing data transfer rates of up to 1 megabit per second in both
directions (symmetrical). SDSL is preferred over Asymmetrical DSL (ADSL) for most
business networking applications. A low-cost SDSL router can provide one or more
Ethernet ports for simple connection to the subscriber's computers or local area network.
Superframe
SF. Any structure made of multiple lower-rate frames.
Telcordia
Previously known as Bellcore (Bell Communications Research), the company now known
as Telcordia Technologies was created during the divestiture of the Bell System in 1984 to
serve the Bell operating companies by providing a center for technological expertise and
innovation.
Telnet
Telecommunications network protocol. A terminal emulation protocol that runs on top of
TCP/IP. Telnet lets a user log into a remote host or server. A user name and password are
normally required. Telnet provides a simple command line interface using text characters.
Originally developed for ARPAnet, Telnet is defined in Internet STD 8 and RFC 854
TR-08
A Telcordia technical requirement for digital loop carrier systems based on the SLC-96
terminal. This interface transports 96 analog telephone lines over four T1 lines connecting
the switch to the TR-08 terminal. Terminals can have up to four shelves (A, B, C, D) with
each shelf terminating up to 24 analog voice lines. The switch manages the terminal
through the out-of-band SLC-96 digital data link (DDL) channel on the T1 connection to
Shelf A
Transmission
Control
Protocol
TCP. A transport layer protocol that offers connection-oriented, reliable stream service
between two hosts. TCP is the primary transport protocol used by TCP/IP applications.
Trap
A monitoring function that triggers an alarm or sends a message when a certain event
occurs or a threshold value is exceeded.
Trunk level 1
T1. A digital transmission link used in North America to transport data at 1.544 million bits
per second. T1 is a facility or service normally delivered over two pairs of copper wires,
one pair for transmit and one pair for receive. Fiber T1 (FT1) uses fiber optics instead of
copper. T1 is based on the DS1 time division multiplexed (TDM) signal carrying 24 DS0
channels