Network Terms "T"

Network Glossary and acronym's

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Tape catalog

A graphical representation of the contents of a backup tape. Windows 2000 automatically creates catalogs during backup and stores them on the tape. The tape catalog shows all the backup sets on a tape.

Tape device

A tape drive which can reads a magnetic storage tape, write data to it, and position it to receive data.

TAPI (Telephony Application Programming Interface)

An API that Windows 2000 communication applications use when they make calls over the telephone line. These calls can include data, fax, and voice.

Target replication partner

A replication partner that receives updates from a source replication partner. Also called a destination replication partner.

T-Carriers

Digital lines that carry data, digitized voice, and digitized video signals. A T-Carrier line multiplexes several channels on to a single physical communication medium. Each channel operates at 64 kilobits per second.

TCP (Transmission Control Protocol)

A reliable protocol that divides data into packets, which the IP protocol then sends to other computers on the network.

TCP/IP

TCP/IP is the protocol suite used on the Internet and on most networks. Nearly all computers today use TCP/IP for communication because it is highly scalable and routable.

TDI (Transport Driver Interface)

A Windows NT boundary layer that gives file system drivers a common programming interface so that they do not have to be tied to specific protocols.

TDR (Time-Domain Reflectometer)

A device you can use to examine the breaks and shorts in a network and identify their locations within a few feet. TDRs work by sending a sonar-like pulse down the cable. The pulse looks for shorts or breaks in the cable and reports their location.

Telecommuter

An employee who works outside the office, at home or on the road, and uses a network or the Internet to communicate with the office.

Telephony Application Programming Interface (TAPI)

An API that Windows 2000 communication applications use when they make calls over the telephone line. These calls can include data, fax, and voice.

Telnet

A protocol that emulates a terminal so you can log on to a remote computer. Also called Virtual Terminal Protocol.

Template

A user account template is a standard user account that you create to simplify creating accounts for other users with similar needs.

Terminal

A terminal with no processor. It accepts keystrokes and displays data from a mainframe computer. Also called a dumb terminal.

TFTP (Trivial File Transfer Protocol)

This data transfer utility provides bi-directional file transfers between two TCP/IP hosts, where one is running the TFTP server software. No user authentication is required.

The Microsoft Network (MSN)

An online network sponsored by Microsoft. You can find answers to technical questions, read articles about Microsoft products, chat with other users, and much more.

Thicknet

Thicknet (sometimes called ThickWire) is a term for the larger size of coaxial cable used in Ethernet local area networks.

Thinnet

Thinnet (sometimes called ThinWire) is a term for the smaller size of coaxial cable used in Ethernet local area networks.

Thrashing

Thrashing is excessive paging. It occurs when the computer spends too much time passing pages between physical memory and the paging file on a hard drive. A symptom of thrashing is that the CPU is under-used but the I/O system is working exceptionally hard.

Thread

An object inside a process that runs program instructions. If an operating system allows it, multiple threads can run on different processors at the same time.

Three-way handshake

A process by which a TCP session is initialized. The purpose of the handshake is to synchronize the sending and receiving of segments, and to communicate to the other host the window size and segment size of data it is capable of receiving.

THT (Token Holding Timer)

A timer in which determines how long each station of an FDDI network can keep the token. Each station has a THT.

Thunking

The process by which Win16 on Win32 (WOW) converts calls from 16-bit applications into 32-bit calls for Win32 functions.

Time to Live (TTL)

A name server caches all of the information that it receives during a process known as iterative queries. The amount of time that the data is stored in cache is referred to as Time to Live. The name server administrator of the zone that contains the data determines the TTL for the data. This parameter can be adjusted. The TTL is a maximum hop count.

Time-Domain Reflectometer (TDR)

Token

In computer networking, a token can be either a physical or a virtual object (often used to authenticate users). Security tokens can be in the form of code, PIN number, or devices like smartcards.

Token Holding Timer (THT)

A timer in which determines how long each station of an FDDI network can keep the token. Each station has a THT.

Token passing

Token passing is a mechanism that uses a digital pass card. Only the system holding the token is allowed to communicate.

Token Ring

A network topology in which computers are connected in a closed ring. Tokens passed from one computer to another allow each computer to use the network.

Tombstone

A tombstone marks the fact that someone deleted an object in the directory. When you delete an object in the directory, that item is no longer part of directory replication. Instead, tombstones are replicated to servers to notify them to delete these objects.

Tombstone lifetime

The tombstone lifetime specifies how long a tombstone will exist before the garbage collection process deletes it as well. A tombstone lifetime should be long enough for directory replication to reach every server in your organization.

Tone generator

A tone generator sends an electronic signal on a wire or cable. Use a tone generator to locate the other end of a specific cable. Generate the tone on one end of the cable, then test the other ends of many cables until you detect the tone.

Topology

The physical layout of a network. Topology describes how the network's computers are connected to each other. Common topologies include buses and rings.

Topology table

A topology table is a record of the updates sent between neighboring routers when a new router is discovered.

Totally stubby area

A totally stubby area does not allow ASBR routes or inter-area routes; only routes within its own specific area are allowed.

Traceroute

Traceroute is a Linux diagnostic utility that tests connectivity between devices, but as it does so it shows the path between the two devices. Responses from each hop on the route are measured three times to provide an accurate representation of how long the packet takes to reach, and be returned by that host.

TRACERT

A Microsoft diagnostic utility that verifies the route used from the local host to a remote host.

Transaction

An entire operation consisting of multiple steps that must all be completed properly, or the entire transaction fails.

Transact-SQL

The standard language for communicating between applications and SQL Server. It is an implementation of ANSI-standard Structured Query Language (SQL) that includes extensions such as stored procedures that make Transact-SQL a full programming language. Sometimes referred to as T-SQL.

Transceiver

A transceiver is responsible for transmitting and receiving network communications. To send signals to the network, the transceiver converts digital data from a PC to digital signals. To receive signals, the transceiver converts digital signals from the network to digital data for the PC. Many transceivers are attached to network interface cards.

Transform file

A file with the .MST extension that can be applied to a Windows Installer package (.MSI file) to customize it. Also called a software modification file.

Transit area

A transit area is an area that has more than one way into itself.

Transit AS peering

Transit AS peering is the communication of information between all EBGP peers. This is optimal for scenarios in which an ISP allows their customers using BGP to access all their other customers using BGP.

Transmission Control Protocol (TCP)

A reliable protocol that divides data into packets, which the IP protocol then sends to other computers on the network.

Transmission Media (Media)

In the realm of information technology, transmission media refers to the cables and wires through which signals (such as electric current or light impulse) are transmitted through a network.

Transport Driver Interface (TDI)

A Windows NT boundary layer that gives file system drivers a common programming interface so that they do not have to be tied to specific protocols.

Transport Layer (OSI Model)

Layer 4 of the OSI reference model. This layer is responsible for reliable network communication between end nodes. The transport layer provides mechanisms for the establishment, maintenance, and termination of virtual circuits, transport fault detection and recovery, and information flow control. Corresponds to the transmission control layer of the SNA model. See also application layer, data link layer, network layer, physical layer, presentation layer, and session layer.

Transport policies

Transport policies (also referred to as transport rules) provide an easy, flexible way for administrators to process, filter, store, and modify all e-mail messages within an Exchange organization. Transport rules allow you to:

Apply corporate policies
Apply compliance policies
Apply content restraints
Manage message routing

Each transport rule consists of three components:

Conditions identify the e-mail messages to which a transport policy action are applied.
Exceptions identify the e-mail messages which are excluded from a policy, even if the message matches a transport policy condition.
Actions modify some aspect of message content or the delivery for e-mail messages that match all the conditions and none of the exceptions of a transport policy.

Transport policy actions

Apply corporate policies
Apply compliance policies
Apply content restraints
Manage message routing

Each transport rule consists of three components:

Conditions identify the e-mail messages to which a transport policy action are applied.
Exceptions identify the e-mail messages which are excluded from a policy, even if the message matches a transport policy condition.
Actions modify some aspect of message content or the delivery for e-mail messages that match all the conditions and none of the exceptions of a transport policy.

Transport policy agents

Transport policy agents apply transport policies to e-mails within an Exchange organization. There are two types of transport policy agents in Exchange 2007:

A Transport Rules agent runs on a Hub Transport server and implements policies set by administrators to all e-mail that travels in and out of an Exchange organization.
An Edge Rules agent runs on an Edge Transport server and helps control spam and unwanted mail flow within an organization.

Transport policy conditions

Apply corporate policies
Apply compliance policies
Apply content restraints
Manage message routing

Each transport rule consists of three components:

Conditions identify the e-mail messages to which a transport policy action are applied.
Exceptions identify the e-mail messages which are excluded from a policy, even if the message matches a transport policy condition.
Actions modify some aspect of message content or the delivery for e-mail messages that match all the conditions and none of the exceptions of a transport policy.

Transport policy exceptions

Apply corporate policies
Apply compliance policies
Apply content restraints
Manage message routing

Each transport rule consists of three components:

Conditions identify the e-mail messages to which a transport policy action are applied.
Exceptions identify the e-mail messages which are excluded from a policy, even if the message matches a transport policy condition.
Actions modify some aspect of message content or the delivery for e-mail messages that match all the conditions and none of the exceptions of a transport policy.

Transport protocol

A type of protocol that allows two computers to communicate with each other. For example, TCP/IP and IPX/SPX are both transport protocols.

Transport rules

Apply corporate policies
Apply compliance policies
Apply content restraints
Manage message routing

Each transport rule consists of three components:

Conditions identify the e-mail messages to which a transport policy action are applied.
Exceptions identify the e-mail messages which are excluded from a policy, even if the message matches a transport policy condition.
Actions modify some aspect of message content or the delivery for e-mail messages that match all the conditions and none of the exceptions of a transport policy.

Transport Rules agent

Transport policy agents apply transport policies to e-mails within an Exchange organization. There are two types of transport policy agents in Exchange 2007:

A Transport Rules agent runs on a Hub Transport server and implements policies set by administrators to all e-mail that travels in and out of an Exchange organization.
An Edge Rules agent runs on an Edge Transport server and helps control spam and unwanted mail flow within an organization.

Triggered update

With the triggered update method (also known as a flash updates), routers that receive updated (changed) information broadcast those changes immediately rather than waiting for the next reporting interval. With this method, routers broadcast their routing tables periodically, punctuated by special broadcasts if conditions have changed. This method reduces the convergence time.

Trivial File Transfer Protocol (TFTP)

This data transfer utility provides bi-directional file transfers between two TCP/IP hosts, where one is running the TFTP server software. No user authentication is required.

Trojan horses

Pieces of software code written expressly to cause problems with servers and workstations. A Trojan horse conceals harmful code inside what looks like a harmless data string or program. Once it is inside a computer, however, it damages data or systems. A Trojan horse is a type of computer virus.

Trunk Cable

The central cable connecting all of the nodes, either inserted directly into the trunk, or nodes tapping into the trunk using offshoot cables called drop cables. Commonly used in the physical bus topology.

Trusts

In a one-way trust, accounts in one domain can be given permission to access resources in another domain. In a two-way, trust, permission is given to each domain to access resources in the other domain.

TTL (Time to Live)

Tunnel

A logical connection that carries encapsulated and possibly encrypted data. Encapsulation and encryption make the tunnel a secure and private link for users across a public network such as the internet.

Tunneling

Tunneling is used primarily to support private traffic through a public communication medium. The most widely known form of tunneling is VPN (Virtual Private Networking). A VPN establishes a secured communications tunnel through an insecure network connecting two systems.

Tunnels provide secure communications, they usually provide less than optimal throughput due to the additional overhead of encryption and maintaining the communications link. Tunnels are not directly associated with password theft or protection.

L2TP, PPTP, and IPSec are all VPN tunnel protocols.