An ITU-T standard addressing Real Time Data Conferencing (Audiographics). See also ITU-T.
A North American Telecommunications term for a digital carrier facility used to transmit a DS1 formatted digital signal at 1.544 Mb/s.
A term for a digital carrier facility used to transmit a DS3 formatted digital signal at 44.736 Mb/s.
A family of digital trunking methods supported in North America. The European counterpart is E-Carrier. See also E-Carrier.
Terminal adapter. A device providing ISDN connectivity to non-ISDN equipment.
Transparent bridging. A system-level concept where the bridges perform MAC address learning and look-ups to determine whether or not a packet on a LAN must be forwarded to another segment. The bridging function is transparent to the end station because the end station does not need to know if the device it is addressing is on the same physical segment. All Ethernet bridges are transparent.
A T-shaped BNC connector used on Ethernet 10BASE2 thin coaxial cable.
Tool Command Language. A set of scripting commands on the Switch Node platform, supported by the BCC.
Transmission Control Protocol. The major transport protocol in the Internet suite of protocols providing reliable, connection-oriented, full-duplex streams. TCP is both an OSI transport layer 4 protocol that regulates source-to-destination communication over virtual circuits and the portion of the TCP/IP protocol suite that governs the exchange of sequential data. See also IP.
Transmission Control Protocol/Internet Protocol. A set of networking protocols designed to link computers from multiple vendors. TCP/IP was originally developed by the Advanced Research Project Agency (ARPA) as part of the UNIX operating system and has been adopted as a networking standard in many government, academic, and technical computing environments.
Transmit data. RS-232-C standard hardware signal to send data from one device to another; also called Tx or Txd.
Time division multiplexer. A device that performs circuit switching. It converts analog signals to digital signals and integrates video, voice, and data applications.
Terminal equipment 1. ISDN-compatible devices, such as a router with an ISDN/BRI module.
Terminal equipment 2. Non ISDN-compatible devices, such as analog phones and PCs.
Bay Networks software providing management access to Bay Networks routers. It may be used to install a router, to maintain router operation, and to monitor and configure various router functions.
A connecting block used in telephone connections, typically consisting of an insulated base covered by four vertical columns of 50 insulation displacement or wire-wrap connectors; also called punchdown block, splice block, Type 66 block, or wiring block.
A 50-pin D connector for 25-pair unshielded twisted pair cable.
A central building or room where distribution cabling is switched and terminated and voice and data communications equipment are located; also called communications closet, equipment room, or wiring closet.
A public packet switched network using the CCITT X.25 protocols. It should not be confused with Telnet.
The Internet standard protocol for remote terminal connection service. The TCP/IP protocol governing the exchange of character-oriented terminal data and described in RFC 854. It allows users of one host to log in to a remote host and interact as normal terminal users of that host.
A device that consists of either a video display and keyboard or a teletypewriter that you use to type and view information. A terminal may be connected to either of the RS-232-compatible serial interface ports on the back panel of the desktop terminal unit.
A type of remote access to a network where a PC or workstation connects to a host computer by emulating an asynchronous or block mode terminal; for example, a VT100 or VT52 terminal emulator program.
A program that allows a computer to emulate a terminal for communication with a mainframe or minicomputer. The workstation thus appears as a terminal, typically a VT100 or VT52, to the remote host.
A device connecting many terminals to a network usually used to reduce the number of cables needed to connect terminals to a mainframe. The terminal server allows terminals to use the LAN as a connection point instead of direct RS-232 serial cables. A terminal server can also connect many network users to its asynchronous ports for dial-out capabilities and printer access. See also LAN.
An electrical impedance attached to the open end of a transmission line to eliminate reflections.
Trivial File Transfer Protocol. A simplified version of FTP that transfers files but does not provide password protection, provide directory capability, or allow transmission of multiple files with one command.
A coaxial cable specified by the IEEE 802.3 10BASE5 standard, approximately 12 mm in diameter and usually colored yellow; also called standard Ethernet, thick Ethernet, ThickNet, or just yellow cable.
A coaxial cable specified by the IEEE 802.3 10BASE2 standard, approximately 5 mm in diameter and usually colored black, to which devices attach by means of BNC T-connectors; also called thin Ethernet or ThinNet.
A limit value associated with a specific parameter or attribute of device or network performance. Detection of this value triggers an appropriate response from the local or remote systems or device. For example, when a threshold value is crossed, a warning message can be sent or a module or port can be partitioned.
The amount of data transmitted end-to-end successfully, per limit of time (usually in a one-second interval).
Token holding timer. A counter on an FDDI ring that controls how long a station can transmit asynchronous frames.
Telecommunications Industry Association. A national trade organization, including members from communications and information technology companies contributing to voluntary industry standards that promote trade and commerce in telecommunications products. http://www.tiaonline.org/
Token ring interface card or token ring interface coupler. An IBM adapter card that allows a controller to attach directly to a token ring LAN.
Token-Ring Link Access Protocol.
Transport layer interface or transport level interface. An interface for transport services (layer 4 of the OSI reference model) that provides a common language to a transport protocol and allows client/server applications to be used in different networking environments.
Tunnel Management Server/System. The Tunnel Management System database resides on a Bay Networks Tunnel Management Server. The database verifies user or domain name information supplied by a remote access server and supplies the server with remote users' tunnel addressing information. See also L2TP, LAC, LNS, VPN.
Delivery of a 3270 data stream via Telnet, provided as part of the TCP/IP protocol suite.
Threaded Neill-Concelman connector. A threaded connector for thin wire Ethernet coaxial cable. See also BNC connector.
A sequence of data bits passed from one node to another around a ring, giving permission to the station possessing the token to send data frames.
The access method used on token ring networks.
A network topology and data signaling scheme in which a special data packet (called a token) is passed from one station to another along an electrical ring. A transmitting station takes possession of the token, transmits the data, then frees the token after the data has made a complete circuit of the electrical ring.
A baseband networking system that operates over shielded twisted-pair copper wires, using a ring topology and token passing access protocol. The original protocol developed by IBM was succeeded by the IEEE 802.5 standard for token ring network communications. Can be run at 4 Mb/s or 16 Mb/s. See also 802.5, Ethernet, LAN.
Bay Networks switching module for token ring networks with wire-speed switching. Part of the Centillion 100 family of switching products.
The physical or logical arrangement of nodes on a network. Physical topology describes the physical relationships between nodes and links. Logical topology is the description of the possible logical connections between network nodes, indicating which pairs of nodes are able to communicate. LANs are usually configured in one of three topologies: star where devices are linked to a central point; ring where devices are connected in a closed loop; or bus where devices are attached to a linear, open-ended cable terminated at each end with a resistive load.
Twisted pair. A cable consisting of two sets of insulated 18- to 24-AWG (American Wire Gauge) wires twisted together to reduce electrical interference, with or without a shield under the outer insulation.
Twisted pair - physical medium dependent. The ANSI standard for running FDDI over UTP wire. Adopted by the IEEE 802.3 for use in 100BASE-TX applications.
A configuration file that lets an interface selectively handle specified network traffic (packets, frames, or datagrams). Using traffic filters, you can instruct a router to block, forward, log, or prioritize certain traffic.
Bay Networks tool included with Optivity Analysis software that assembles information gathered by multiple NMMs and presents the data in a traffic map to aid in identifying redundant links, traffic bottlenecks, and misconfigured internetworking devices.
Part of a packet (message data surrounded by a header and trailer) that carries special information used by the network to the destination station.
Transmitter-receiver. An internal or external device for receiving and transmitting data; for example, an IEEE 802.3 medium attachment unit (MAU), through which Ethernet stations attach to the network cabling medium and which provides circuitry to convert signals between a form suitable for the network and a form suitable for the station.
A cable used to connect a station's AUI port to a transceiver; also called AUI cable, drop cable, or transceiver drop cable.
Aspects covering transmission, multiplexing, and switching in a telecommunications network.
Bridges between source routing networks (SRB) and transparent bridge networks. These bridges allow end stations using different bridging techniques to communicate as though they used the same bridging technique. See also transparent bridging (TB), SRB.
A device, such as a router, that connects dissimilar MAC-layer networks (Ethernet to FDDI, for example) together. All translational devices are store and forward.
The minimum peak power injected into an optical fiber by the transmitter.
A system-level concept where the bridges perform MAC address learning and look-ups to determine whether or not a packet on a LAN must be forwarded to another segment. The bridging function is transparent to the end station because the end station does not need to know if the device it is addressing is on the same physical segment. All Ethernet bridges are transparent.
Layer 4 of the OSI reference model, responsible for reliable end-to-end data transfer between end systems. Manages the transfer of data from a source program to a destination program.
An alarm message that a monitored device sends to the management station whenever that device detects an alarm condition. Alarm conditions include device errors, network errors, status changes, and threshold values exceeded.
Bay Networks software application that works with the Optivity network management application and collects and displays data showing long-term performance trends to aid in planning network expansion. Used to baseline Ethernet, token ring, and FDDI network performance.
Token rotation timer. A timer that controls FDDI ring scheduling during normal operation and detects serious ring errors.
A main or high-bandwidth communication cable between a telco central office and a PBX or between PBXs in different locations.
Cable that connects the ring in (RI) and ring out (RO) ports on token ring hubs in order to connect more than one hub to the token ring network.
A link that connects two trunk ports. For Bay Networks modular and Fast Ethernet switches, trunk links can be either 100 Mb/s full-duplex or 200 Mb/s full-duplex, but not 10 Mb/s.
An expansion port or attachment port used to connect two Bay Networks modular or Fast Ethernet switches.
Time to live. The TTL counter specifies the maximum number of hops that an IP data packet can traverse in the network before an intermediate router discards the packet, thus preventing packets from looping endlessly through the network.
Target token rotation timer. Part of the FDDI token claim process. When the ring is initialized by stations inserting onto the ring, the TTRT of each frame is checked and the frame that contains the lowest TTRT wins the claim.
A virtual, direct pathway with which to transmit bidirectional traffic between two end points. See also VPN.
A mechanism of forwarding traffic from remote users to a corporate network through an existing public IP network. Data is encapsulated within an IP datagram and then decapsulated at the other end point of the tunnel. See also BayDVSTM, GRE, VPN.
The establishment and tearing down of virtual (IP) tunnels, based on server and remote user information. See also TMS, VPN.
Valid transmission timer. In an FDDI network, the valid transmission timer is used to recover from transient ring errors.
A cable consisting of two sets of insulated 18- to 24-AWG (American Wire Gauge) wires twisted together to reduce electrical interference, with or without a shield under the outer insulation.
Transmit. RS-232-C hardware standard signal sending information from one device to another; also called TD.
TX is also used to indicate the medium type, as in 100BASE-TX (indicating UTP connection).
A shielded twisted-pair cable used as distribution cable in the IBM Cabling System. See also IBM Cabling System.
A shielded twisted-pair cable used as distribution cable in the IBM Cabling System, the same as Type 1 cable with the addition of four voice-grade pairs. See also IBM Cabling System.
A flexible shielded twisted-pair cable used for patch cables or short-distance distribution cables in the IBM Cabling System. See also IBM Cabling System.
A flat shielded twisted-pair cable used for under-carpet wiring in the IBM Cabling System. See also IBM Cabling System.
A thin shielded twisted-pair cable used as low-cost, short-distance distribution cable in the IBM Cabling System. See also IBM Cabling System.
A connecting block used in telephone connections, typically consisting of an insulated base covered by four vertical columns of 50 insulation displacement or wire-wrap connectors; also called punchdown block, splice block, telco block, or wiring block.