T

T1
T1 is one of the T-carrier telecommunication standards for multiplexing digitized voice signals. A T1 channel operates at 1.544 Mbps. Each T1 channel (64 Kbps) carries a digitized representation of an analog signal that has a bandwidth of 4,000 Hz. Originally, 64 Kbps was required to digitize a 4,000-Hz voice signal. Current digitization technology has reduced that requirement to 32 Kbps or less; however, a T-carrier channel is still 64 Kbps.

T1, T3
T1 and T3 are two services of a hierarchical system for multiplexing digitized voice signals. The first T-carrier was installed in 1962 by the Bell system. The T-carrier family of systems now includes T1, T1C, T1D, T2, T3, and T4 (and their European counterparts E1, E2, etc.). T1 and its successors were designed to multiplex voice communications. Therefore, T1 was designed such that each channel carries a digitized representation of an analog signal that has a bandwidth of 4,000 Hz. It turns out that 64 Kbps is required to digitize a 4,000-Hz voice signal. Current digitization technology has reduced that requirement to 32 Kbps or less; however, a T-carrier channel is still 64 Kbps. A T1 line offers bandwidth of 1.544 Mbps; a T3 offers 44.736 Mbps.

Tempest
Tempest is a U.S. government code word that identifies a classified set of standards for limiting electromagnetic data radiation from electronic equipment such as computers or peripheral devices. Tempest-compliant hardware ("tempested" hardware) is shielded to prevent data from being inadvertently transmitted through the device case, electrical wiring, or nearby antennas.

Thicknet
Thicknet is also known as 10Base5 or Yellow Wire. Thicknet can carry a signal 500 meters before a repeater is required. The maximum number of nodes allowed in a trunk segment is 100. The maximum number of trunk segments allowed in an Ethernet network is five, of which only three may be populated with nodes. Thicknet is no longer installed in computer networks.

Thinnet
Thinnet (or 10Base2) can carry a signal 185 meters before a repeater is required. The maximum number of nodes that can be connected to a Thinnet trunk segment is 30.

Tie Line
A private leased line that directly links two telephones or telephone systems is referred to as a tie line.

Time-Division Multiplexing (TDM)
TDM is a multiplexing technology that guarantees each port a fixed amount of bandwidth on a rotating basis. TDM is suited to constant bit rate traffic.

Token Ring
Token Ring is a LAN protocol used in computer networks. Token Ring operates at 4 and 16 Mbps.

Topology
Topology refers to the specific physical configuration of a network or a portion of a network. Ring and star are examples of different network topologies.

Traffic
Traffic refers to the combination of information flow going to and from devices attached to a network.

Traffic Monitor
A traffic monitor is a device that monitors the status and performance of Physical Layer media, such as cables or leased lines, which are too simple to include their own SNMP agents.

Trap
In SNMP, a trap is an unsolicited report from an agent. A trap notifies the central NMS of certain predefined conditions and changes of status. When traps are received at a certain software destination in the NMS, they can trigger certain actions, such as automatically paging the person who can correct the particular situation reported by the agent.

Transmission Control Protocol (TCP)
TCP is normally used in conjunction with IP in a TCP/IP-based network. The two protocols working together provide for connectivity between applications of networked computers.

Transmission Control Protocol/Internet Protocol (TCP/IP)
TCP is a Transport Layer protocol used to send messages reliably across a network. It is usually paired with IP. TCP/IP also describes suites of protocols, software, and applications designed to work over networks based on TCP and IP.

Transport Driver Interface (TDI)
TDI is the Windows NT interface layer between various transport protocols (Sequenced Packet Exchange [SPX] or TCP) and server or redirector software interfaces.

Tunneling
The process of encapsulating one network protocol within the packets of another is referred to as tunneling. For example, tunneling can be used to encapsulate various network protocols within IP packets for transmission across the Internet. The encapsulated data is encrypted, creating a secure VPN.

Twisted Pair
A twisted pair line, as the name implies, consists of a pair of wires twisted together.