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Terminologies Simplified

SONET (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.