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(Synchronous Optical Network): A high-speed network technology
that provides data transfer rates from 51.8 Mbps to 9.953
Gbps using fiber-optic cabling.
SOCKS (Socket secure): A security protocol used to
communicate through a firewall or proxy server.
The SOCKS protocol uses TCP/IP sockets for communication.
SPID (Service Profile Identifier): SPID is the number
used by your ISDN service provider to identify services on
your ISDN line. A SPID informs the service provider's central
office about the capabilities of each ISDN terminal (like
whether the terminal accepts voice or data) on the B-channels.
Source-route bridging: A bridging technology that can
determine the path on which data is transferred from one workstation
to another. Source-route bridges execute the routing instructions
placed into each data packet upon assembly.
Switched circuit: A temporary connection between endpoints
established for the duration of a call over which two parties
exchange data. The circuit is disconnected when the call ends.
Splitterless DSL: An ADSL installation standard (ITU-T
G.992.2) developed by the Universal ADSL Working Group that
provides a data transfer rate from 1.544 Mbps to 6 Mbps downstream
and 128 Kbps to 384 Kbps upstream.
Switched-56: A data service consisting of a single
56 Kbps channel. This service is available over any type of
line. It is the only service available to T1 access lines
and Switched-56 lines. Because Switched-56 was the first available
data service, both the service itself and the lines that accessed
it were called Switched-56. However, any type of line can
now access Switched-56 data service.
Switched-64: A data service consisting of a single
64 Kbps channel. This service is available over T1 PRI and
ISDN BRI lines only.
Star-wired ring topology: A star-wired ring topology
may appear (externally) to be the same as a star topology.
Internally, a star-wired ring contains wiring that allows
information to pass from one device to another in a circle
or ring. The token-ring protocol uses a star-wired ring topology.
Synchronization: The method of ensuring that the receiving
end can recognize characters in order in which the transmitting
end sends them in a serial data transmission is called synchronization.
Without synchronization, the receiving end would perceive
data simply as a series of binary digits with no relation
to one another.
STS (Synchronous Transport Signal): STS is a standardized
electrical signal that is considered the building block of
SONET multiplexing hierarchy.
Stateful filter: A filter that identifies suspicious
packets by looking at packet addresses and the context of
the session in which the packets are sent.
SAN (Storage Area Network): A high-speed subnetwork
that interconnects different data storage devices with associated
data servers for a large network. SANs support disk mirroring,
backup and restore, archival and retrieval of archived data,
data migration from one storage device to another, and the
sharing of data among different servers in a network.
T1 line: A T1 line consists of twenty-four 64 Kbps
channels. A T1 line uses copper wire and spans distances within
metros. There are 2 types of T1 lines: T1 access lines and
T1 PRI lines.
T1 access line: A 1.544 Mbps T1 line that provides
twenty-four 56 Kbps data channels and uses inband signaling.
This type of line can contain all switched channels, all nailed-up
channels, or a combination of switched and nailed-up channels.
T1 PRI line: A T1 PRI line uses twenty three B channels
for user data, and one 64 Kbps D channel for ISDN D-channel
signaling. The B channels can be all switched, all nailed
up, or a combination of switched and nailed up. PRI stands
for Primary Rate Interface.
TACACS (Terminal Access Concentrator Access Control Server):
TACAS is a very simple query/response protocol that enables
the MAX to check a user's password, and enable or prevent
access. A TACACS server supports only the basic password exchanges
that PAP uses; it does not support CHAP.