Table Of Contents

glossary

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A

AAA

Triple A security in billing that stands for authentication, authorization and accounting.

access charge

Charges long distance providers pay to local telephone service providers for use of the local network to complete long distance calls.

access line

The circuit between a telephone subscriber and the local switching center.

access server

Communications processor that connects asynchronous devices to a LAN or WAN through network and terminal emulation software. Performs both synchronous and asynchronous routing of supported protocols. Sometimes called a network access server. See also communication server.

accounting management

One of five categories of network management defined by ISO for management of OSI networks. Accounting management subsystems are responsible for collecting network data relating to resource usage. See also configuration management, fault management, performance management, and security management.

address

Data structure or logical convention used to identify a unique entity, such as a particular process or network device.

address mapping group (RMON2)

A list of MAC addresses that correspond to the network addresses discovered by the SwitchProbe device.

address mask

Bit combination used to describe which portion of an address refers to the network or subnet and which part refers to the host. Sometimes referred to simply as mask. See also subnet mask.

administrative applications

TrafficDirector applications performed by a network administrator that concentrate on performing the necessary configuration tasks to functionally link data-monitoring devices to utilities that display the monitored data.

advertising

Router process in which routing or service updates are sent at specified intervals so that other routers on the network can maintain lists of usable routes.

agent

Firmware embedded or software installed on a device.

agent group

A collection of one or more agents created by a network administrator. The TrafficDirector application handles an agent group as a single agent, allowing you to collectively monitor network statistics from more than one segment or point on a segment.

alarm

SNMP message notifying an operator, or administrator, of a network problem. Similar to event or trap. Notification that a threshold (rising or falling) established by the user has been met.

alarm discovery

Alarm information displayed on the lower half of the Domain Discovery window that includes alarms configured on an agent. You can obtain additional details by selecting a specific alarm.

alarm group (RMON1)

Periodically takes statistical samples from variables in the SwitchProbe device and compares them with previously configured thresholds. If the monitored variable crosses a threshold, an event is generated. A mechanism is implemented to limit the generation of alarms. This group includes the alarm Table and requires the implementation of the Event group. Elements include alarm type, interval, starting threshold, and stop threshold.

alert

A message sent to all IP addresses defined in the trap community string.

Alert Monitor

A TrafficDirector application that displays alerts when a threshold is met.

All Conversations

A TrafficDirector application that displays, for a selected domain, all conversations taking place between a pair of hosts.

All Talkers

A TrafficDirector application that displays, for a selected domain, all talkers seen by the agent connected to the network segment.

analog signal (AS)

A signal in the form of a continuous varying physical quantity, e.g. , voltage, which reflects variations in some quantity, like loudness in the human voice.

analyzer port

A port on a switch designated by the switch management console to host a SwitchProbe device or analyzer. This port is most often put in receive-only mode and packets are mirrored to it when the mirroring function is activated.

assigned numbers

RFC [STD2] documents the currently assigned values from several series of numbers used in network protocol implementations. This RFC is updated periodically, and current information can be obtained from the IANA. If you are developing a protocol or application that will require the use of a link, socket, port, protocol, and so forth, contact the IANA to receive a number assignment.

async interface

Asychronous interface is used to terminate analog (async) dialin calls.

asynchronous transmission

This term describes digital signals that are transmitted without precise clocking. Such signals generally have different frequencies and phase relationships. Asynchronous transmissions usually encapsulate individual characters in control bits (called start and stop bits) that designate the beginning and end of each character. A method of sending data over a communications line by placing a block of transmitted bits in an "envelope." The envelope begins with a "start" bit that tells a computer a character is beginning. The "stop" bit sends a message that a character has ended. Asynchronous transmission also has the advantage of not needing precise clocking mechanisms that maintain a time relationship between transmitter and receiver.

Asynchronous Transfer Mode (ATM)

An international packet switching standard. The standard uses a cell-switched approach, in which each packet of information features a uniform size of 53 bytes (digital words of eight bits each). Of the total cell, 48 bytes is the "payload," or information to be transmitted. Five bytes are used as a "header," providing all the addressing information for that particular packet. ATM could switch and route information of all types, including video, voice and data.

authentication

In security, the verification of the identity of a person or process.

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B

B channel

Bearer channel. In ISDN, a full-duplex, 64-kbps channel used to send user data. Compare to D channel, E channel, and H channel.

backplane

Physical connection between an interface processor or card and the data buses and the power distribution buses inside a chassis.

bandwidth

Difference between the highest and lowest frequencies available for network signals. The term is also used to describe the rated throughput capacity of a given network medium or protocol. The transmission capacity of a telecommunications link (e.g., 64 kbps).

baseband

The total frequency band occupied by the aggregate of all the voice and data signals used to modulate a radio carrier.

baseline report

Compares two similar time ranges in one report. A baseline time range is maintained (protected against purge action) so that baseline data is available at report time. The baseline time range can be one to 30 days. You can baseline both detail and summary data, and you can store up to two baseline time ranges. However, the comparison reports run on any two time ranges where data is available. The baseline comparison is a one-to-one comparison; therefore, no computation of average, minimum, maximum, or standard deviation is performed on the baseline data.

basic service

The minimum set of capabilities deemed necessary for use of the public telecommunications network. Current basic service includes an access line (usually one-party, analog, rotary dial), access to local and long distance calling, access to emergency calling (911), and access to voice/nonvoice relay service.

baud

A unit of signaling speed. The speed in Baud is the number of discrete conditions or signal elements per second. If each signal event represents only one bit condition, then Baud is the same as bits per second. Baud does not equal bits per second.

Bell operating company (BOC)

A local telephone company formerly owned by AT&T.

Bellcore

Bell Communications Research. Organization that performs research and development on behalf of the RBOCs.

Broadband Integrated Services Digital Network (BISDN)

A high speed ISDN service intended to support full motion video and image applications, as well as data, at speeds of approximately 150 Mbps.

bit

A binary digit, the smallest unit of information in a computer, represented as a 0 or 1. One character is typically seven or eight bits in length.

bit rate

The speed at which digital signals are transmitted, expressed in bits per second.

bit/byte

A bit is the most basic element of digital information. One bit represented by either a 0 or 1, the absence or presence of electricity or light is combined with other bits to form an eight-bit word or Byte. Bytes are the words of our digital language. Depending on how the bits within them are ordered, these bytes can be translated into numbers, words, or commands.

bps

Bits per second, used to refer to transmission speeds of sending data (e.g., 2400 bps, 14,400 bps, etc.). Speed takes on particular importance when using on-line Internet services. See also "kbps."

Basic Rate Interface (BRI)

This ISDN scheme is identified as 2B+D, and permits two "bearer" channels, each operating at 64 kbps, and one "data" channel, operating at 16 kbps, to be carried over a single twisted pair copper wire.

broadband

A transmission facility having a bandwidth of greater than 20 kHz. Any communications system able to deliver multiple channels or services of video, voice, or data to its users or subscribers over a broad band of RF spectrum.

broadcast address

Special address reserved for sending a message to all stations. Generally, a broadcast address is a MAC destination address of all ones.

bus

Common physical signal path, or highway, composed of wires or other media across which signals can be sent from one part of a computer to another.

byte

A collection of bits used to form a character or some other information.

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C

call

Establishment of (or attempt to establish) a voice or data connection between two endpoints, or between two points which provide a partial link (e.g. a trunk) between two endpoints.

capture group (RMON 2)

Storage of packets, based on filters, for later retrieval.

carrier

A long distance company which uses primarily its own transmission facilities, as opposed to resellers which lease or buy most or all transmission facilities from carriers. Many people refer to any type of long distance company, whether it has its own network or not, as a carrier, so the term is not as restrictive as it used to be.

Channel-Associated Signaling (CAS)

Comitre Consultatif Internationale de Telegraphique et Telephonique (CCITT)

An international group operating under the auspices of the International Telecommunications Union (ITU) and charged with establishing telecommunications standards. Name recently changed to ITU-TSS (International Telecommunications Union-Telecommunications Standards Sector).

cell

An ATM unit of segmented data that consists of 53 bytes or octets. Of these, five constitute the header and the remaining 48 carry the data payload. Cell-switching gives maximum utilization of physical resources.

central office (CO)

The telephone company facility housing the switches and other equipment that provide telephone service for customers in an immediate geographical area.

channel

A transmission path between two points. For example, a DS0 in a T1 line.

circuit

A path for the transmission of electromagnetic signals to include all conditioning and signaling equipment.

circuit switching

The type of signal switching traditionally used by telephone companies to create a physical connection between a caller and a called party.

Cisco IOS

Cisco-proprietary Internetwork Operating System.

Cisco Discovery Protocol Media (CDP)

The protocol-independent, device-discovery protocol that runs on all Cisco-manufactured equipment including routers, access servers, bridges, and switches. Using CDP, a device can advertise its existence to other devices and receive information about other devices on the same LAN, or on the remote side of a WAN. Runs on all media that support SNAP, including LANs, Frame Relay, and ATM.

Command Language Interpreter (CLI)

Basic Cisco IOS configuration and management interface.

client

End-user computer on a network (local or Internet).

client/server

A distributed computing architecture in which numerous dispersed terminals, each has its own central processor and memory, communicates with centralized processing, storage and output resources. In a client/server network, the client is a front end resource for a user, while the server represents the back end set of resources. Servers include mainframe computers, minicomputers, personal computers, hard disk, and other types of memory devices. Clients typically are personal computers. Client/server also is a concept used by software programs running on distributed computing platforms. In a cable TV context, a client is a set top terminal or other intelligent device at a customer premises.

coaxial cable

Cable that has been used for cable television installation. Being replaced by fiber optic cable of greater capacity and bandwidth.

command line interface

The TrafficDirector command-line interface on UNIX. Accessible at the shell prompt on UNIX, and accessible at the DOS prompt on Microsoft Windows. When invoked, displays CLI usage options.

common carrier

An entitry that provides a public communications conduit without regard to content.

communications protocol

A collection of rules that ensure compatibility of transmitting and receiving equipment. Protocols usually have three main parts, the method by which data is coded, the method by which codes are received, and the methods used to establish control, detect errors and failures, and intiate corrective action.

Configuration Manager

A TrafficDirector application allows you to add and configure agents, agent groups, switches, and Frame Relay agents. Configuration Manager also provides a means for installing domains, logging, traps, and resources on a variety of agents including DLCIs and switch ports.

Configuration Rollup (or Config Rollup)

A TrafficDirector application that allows you to define the number of days that different kinds of data are stored in an SQL report database before being deleted.

constrained modem pool

A modem pool that has a condition imposed on the starting and ending modem numbers for it pool sub-ranges. The condition is that the start of a pool sub-range must coincide with the start of a modem module, and the end of a pool sub-range must coincide with the end of a modem module.

constraint-capable modem pool

A constraint-free modem-pool that has its pool sub-ranges specified that the conditions for a constrained modem-pool are met.

constraint-free modem pool

A modem pool that has no conditions imposed on the starting and ending modem numbers for its pool sub-ranges. A modem pool is created by default to be constraint-free.

customer premises equipment (CPE)

Equipment employed at the clients location or premises (other than a carrier) to originate, route, or end telecommunications.

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D

D-channel (ISDN)

This is the 24th timeslot on T1/PRI or the 16th timeslot on E1/PRI and is used for signaling information. Call setup and teardown information is sent over the D-channel.

default firmware

The modem firmware in a firmware list that would be loaded on the modem modules in the absence of any modem firmware-related configuration commands. This will always be the first firmware image in the firmware list.

demodulation (MOD)

The process of retrieving data from a modulated signal.

dial interface

These interfaces are used for ending digital calls. Dialer interfaces are also used for async calls.

dial pulsing (DP)

The transmitting of telephone address signals by momentarily opening a DC circuit a number of times corresponding to the decimal digit which is dialed. Transmission and/or reception of address digits using "onhook" and "offhook" transitions of the DC signaling variable.

dial selective signaling (DSS)

A multipoint network in which the called party is selected by a prearranged dialing code.

dial tone (DT)

A tone indicating that automatic switching equipment is ready to receive dial signals.

dialing parity

A company that is not an affiliate of a local phone company is able to provide phone services in such a manner that customers have the ability to route their calls automatically without the use of any access code.

digital transmission

Transmission of data, audio, or video messages in discrete codes generated by computers.

domain

The name of a computer or network on the Internet, specifically the characters to the right of the "@" sign, indicating the organization and the type of organization (.mil=military; .org=nonprofit; .edu=educational institution; .com=commercial, etc.) that operates that domain or the physical location of the computer (.ca=Canada, .uk=United Kingdom)

DS3

Digital signal level 3. Framing specification used for transmitting digital signals at 44.736 Mbps on a T3 facility. See also E3 and T3.

DS0 Channel

Digital Signal Level 0. A 56 or 64 kbit/s channel. The DS0 channels for the T1 also pass signaling information using "robbed-bit" signaling.

duplex signaling (DS)

A long-range bidirectional signaling method using paths derived from transmission cable pairs. It is based on a balanced and symmetrical circuit that is identical at both ends. This circuit presents an E&M lead interface to connecting circuits.

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E

E3

Wide-area digital transmission scheme used predominantly in Europe. E3 carries data at a rate of 34.368 Mbps. See also DS3. Compare with T3.

egress interface

Egress interfaces are network connections, or ports, used for outbound traffic flow.

EIA/TIA-232

Common physical layer interface standard, developed by EIA and TIA, that supports unbalanced circuits at signal speeds up to 64 kbps. Closely resembles the V.24 specification. Formerly called RS-232.

eligible telecommunications carrier

A telecommunications carrier is eligible to receive universal service support, if it offers phone service to all customers throughout a service area without preference, and it advertises the available supported services through the mass media.

Email

Electronic mail. Messages are composed on computers and then sent over a network, in electronic form to other network users.

Ethernet

Baseband LAN specification originated by Xerox and developed jointly by Xerox, Intel, and Digital Equipment Corp. Nodes on Ethernet networks use CSMA/CD to contend for access to the transmission medium. 10-Mbps Ethernet includes specifications for many different cable types, including 10Base2, 10Base5, 10BaseF, 10BaseT, and 10Broad36. A newer standard, Fast Ethernet, calls for data to be carried at 100 Mbps. Ethernet is similar to IEEE 802.3.

exchange access

The offering of access to telephone exchange services or facilities to originate or end telephone toll services.

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F

faceplate

The front panel of a plug-in module such as a line card or power supply.

Federal Communications Commission

Government agency that regulates wire, satellite, and over-the-air transmissions.

fiber optic

The rapid transmission of light pulses in a coded digital format through the fiber cable. In a fiber optic transmitter, a light source such as a laser or light-emitting diode (LED) is connected to the fiber cable. This light source converts an electronic input signal into a series of light pulses (representing bits) by blinking on and off millions of times per second. This stream of light pulses is the combination of many lower rate bit streams formed using digital multiplexing techniques. At the other end of the fiber, fiber optics receivers capture the light pulses for conversion to electrical signals.

fiber optic cable

Cable that consists of several strands of glass-like material capable of transmitting modilated light using a laser, with the capacity of 600 times that of coaxial cable.

File Transfer Protocol (FTP)

The first and most fundamental way to transfer files to and from remote computer sites. "Anonymous ftp" refers to accessing public file archives without a password (login=anonymous, password=your email address).

firmware list

The list of available bundled modem firmware images in the modem card image running in a particular modem slot.

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G

grade of service (GS)

The probability of a call being blocked by busy trunks, expressed as a decimal fraction, and usually meaning the busy-hour probability.

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H

host

On the Internet, a host, or host computer, can serve as both way station and entry point for network users. Hosts serve information to remote users, for example using World Wide Web or Gopher. They also provide access to the Internet for local users, capable of logging in through a particular account. A host is similar to node, except that "host" usually implies a computer system, whereas "node" generally applies to any networked system, including access servers and routers. See node.

hypertext

The World Wide Web is built around this concept. Documents are formatted with special tools that permit authors to link information to other documents of relevance elsewhere on the Internet. The Web is composed of "pages," documents written in hypertext, or HyperText Markup Language (HTML). Using this information, graphical browsers like Mosaic or Netscape display images and text. By clicking on highlighted text, one can move to related information and images located anywhere around the world, reading and accessing countless pages of online information in various media (audio, video, pictures, etc.). A nongraphical browser called Lynx also enables access to Hypertext documents, with keystrokes instead of a mouse.

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I

information service

The offering for generating, acquiring, storing, transforming, processing, retrieving, utilizing, making information available using telecommunications. This service includes electronic publishing, but does not include management, control, or operation of a telecommunications system or the management of a telecommunications service.

ingress interface

Interfaces used for inbound traffic flow.

interexchange carrier (IXC)

Telecommunications providers that provide service between local service areas.

Internet

An international network of computer networks with common protocol standards. World wide computer interconnection. Provides any computer with the capability of linking to any and all other computers through mainframe computer links and telephone connections.

IOS

See Cisco IOS.

IP address

The 32-bit address assigned to hosts using TCP/IP. An IP address belongs to one of five classes (A, B, C, D, or E) and is written as four octets separated by periods. This is called dotted decimal format. For example: 172.16.211.0. Each address consists of a network number, an optional subnetwork number, and a host number. The network and subnetwork numbers together are used for routing, and the host number is used to address an individual host within the network or subnetwork. A subnet mask is used to extract network and subnetwork information from the IP address. Also called Internet address. See also IP and subnet mask.

IP address pools

Administratively defined numeric group of available internet protocol (IP) network device identifier. Range of numeric IP addresses set aside for a specific allocation purpose, such as DHCP. As clients connect to the Network Access Server (NAS), they request and are assigned an IP address from the configured IP address pool.

Integrated Services Digital Network (ISDN)

In its simplest form, called Basic rate ISDN, it provides a means of transmitting two voice channels (each operating at 64 Kbps) and one data channel (operating at 16 Kbps) over a single pair of twisted copper conductors. The two voice channels are called bearer, or "B" channels; the single data channel is the "D" channel. A more complex form of ISDN is called Primary rate ISDN; in this system there are 23 "B" channels operating at 64 Kbps and one "D" channel operating at 64 Kbps. Thus the transmission capability of Basic rate is 144 Kbps, and that of Primary rate ISDN at 1.5 Mbps.

Internet service provider (ISP)

A company that allows home and corporate users to connect to the Internet.

ITU-T

International Telecommunications Union, Standardization Sector. ITU-T is the telecommunication standardization sector of ITU. This sector is responsible for making technical recommendations about telephone and data (including fax) communications systems for service providers and suppliers. The ITU-T carries out the functions of the former CCITT. A sister organization, ITU-R, carries out similar functions for radio.

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L

local area network (LAN)

A limited distance network connecting a defined set of terminals. It could connect workstations within an office, offices in a building, or buildings within a campus.

leased line

A dedicated telephone line for whatever purpose designated by the lessee. Leased lines are capable of higher transmission speeds for data communications than regular telephone lines, and are often required for large computers with multiple users connecting simultaneously to the Internet.

line

(a) From a switching viewpoint, the Loop, Station Equipment and Central Office - associated equipment assigned to a customer. (b) From a Transmission view point , the transmission path between a customers station equipment and a switching System (also called a Loop). (c) In Carrier Systems, the portion of the transmission system between two terminal locations. The line includes the transmission media and associated line Repeaters. (d) The side of the Central Office equipment that connects to the Outside Plant. The other side is called the drop side.

line signaling

When configuring a router for signaling, line signaling can be used for both inbound and outbound calls. The line signaling configuration must match the corresponding telco switch configuration.

local area network (LAN)

Intraoffice communication system usually used to provide data transmission in addition to voice transmission.

local exchange carrier (LEC)

Any company that is engaged in the provision of telephone exchange service or exchange access.

loopback

A method of performing transmission tests on a circuit not requiring the assistance of personnel at the distant end. A diagnostic test that returns a transmitted signal to the sending device after it has passed through a network or across a particular link. The returned signal can then be compared to the transmitted one. The discrepancy between the two helps you to trace faults. When you are trying to locate a faulty piece of equipment, you can use repeated loopbacks to eliminate healthy machines until the problem is found.

loopback interface

A logical interface on the router that can be used for diagnostics and troubleshooting purposes. It is also used to conserve address space so other physical interfaces can be unnumbered to this interface. The state of the Loopback interface is always UP/UP.

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M

management information base (MIB)

A database of network management information that is used and maintained by a network management protocol such as CMIP (Common Management Information Protocol) or SNMP (Simple Network Management Protocol). The value of a MIB object can be changed or retrieved using CMIP or SNMP commands, usually through a GUI-based network management system. MIB objects are organized in a tree structure that includes public (standard) and private (proprietary) branches.

MICA

Multiservice Cisco IOS Channel Aggregation. Technology that enables the simultaneous support of remote-access users through both analog modems and ISDN devices.

modem

A device that converts digital signals generated by a computer into analog signals for transmission over telephone lines. Modems also convert analog signals from telephone lines into digital signals for computer use. (The term stands for modulator/demodulator).

modem pools

The modem pool covers a specified range of modems that accept calls based on the number called by dialin users. If there is only one dial-in number, then all modems can be defined under the default modem pool. It is also used for modem firmware upgrades.

modulation

Alterations in the characteristics of carrier waves. Usually impressed on the amplitude and the frequency.

Multilink virtual template

A virtual template from which the specified Multilink PPP bundle can clone its interface parameters.

multiplexing

Creating multiple channels by interspersing more than one signal over a single relay, such as cable, or microwave.

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N

network

A group of stations linked together to broadcast the same program simultaneously. Also used as designate cable program providers.

network element

A facility or the equipment used in the provision of a telecommunications service. The term includes subscriber numbers, databases, signaling systems, and information sufficient for billing and collection. It is also used in the transmission, routing, or other provision of a telecommunications service.

network trunks

Circuits connecting switching centers.

node

Endpoint of a network connection or a junction common to two or more lines in a network. Nodes can be processors, controllers, or workstations. Nodes, which vary in routing and other functional capabilities, can be interconnected by links, and serve as control points in the network. "Node" is sometimes used generically to refer to any entity that can access a network, and is frequently used interchangeably with "device." See also host.

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O

offline

The absence of connection to another computer. In an "off line" mail system, the user reads and writes e-mail messages in an editor without a modem connection to a remote computer. Another piece of software then automatically establishes a connection to a remote host computer, sends and receives accumulated e-mail, then hangs up. This is less interactive than online systems, but tends to be cheaper for the user and is sometimes a necessity in areas with particularly bad telephone lines.

online

A "live" connection to another computer. In an online e-mail system, a user works directly with a remote host computer, reading and sending e-mail while connected to that computer. Interactive Internet functions like WWW and Gopher require an online interface.

override firmware

The modem firmware that is indicated as the alternate firmware image to which the modem module is to be upgraded.

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P

packet

A bundle of data packaged for transmission over a network. Packets can be various lengths, ranging from about 40 bytes up to 32,000 bytes on the Internet, but typically about 1,500 bytes in length. The Asynchronous Transfer Mode, a new standard for switching data of various types over private and public networks, specifies a packet of uniform 53 byte length.

personal communication service (PCS)

Wireless technology that offers ways to exchange voice and data. Competition for cellular telephones.

point of presence (PoP)

A physical location within a LATA at which an IC establishes itself for the purpose of obtaining LATA access, and to which the BOC provides access services.

point-to-point

A communications circuit between two terminations which does not connect with a public telephone system.

pool subrange

A contiguous range of modems. The pool-range set for a modem-pool is the logical union of a set of pool sub-ranges.

port

Entrance or access point to a computer, multiplexor device, or network where signals may be supplied, extracted, or observed.

public switched telephone network (PSTN)

General term referring to the various telephone networks and services in place worldwide. Sometimes called plain old telephone service (POTS).

protocol

A set of rules about how computers act when talking to each other. Standard protocols are Ethernet, IEEE 802.5 token ring, X Modem or Kermit.

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Q

quality of service (QoS)

A contracted data rate that is negotiated between two ATM end points that guarantees throughput and data delivery. A measurement of performance for a transmission system that reflects its transmission quality and service availability.

queue

A temporary delay in providing service caused by the inability of the system provided to handle the number of messages or calls attempted.

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R

regional Bell operating company (RBOC)

Corporate entities that emerged from the breakup of the AT&T monopoly to own local telephone service in designated geographic regions in the USA.

remote access (ra)

The ability of transmission points to gain access to a computer that is at a different location.

routing protocol

Protocol that accomplishes routing through the implementation of a specific routing algorithm. Examples of routing protocols include RIP, IGRP, EIGRP, OSPF, and BGP.

RS-232

See EIA/TIA-232.

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S

server

The main computer on a network, including local area networks (LANs) and hosts on the Internet. So called because it "serves" software or information to the "client" computers on the network.

service provider

A company or organization that provides e-mail or Internet connectivity, typically for a fee.

Stack Group Bidding Protocol (SGBP)

Aprotocol used for configuring Multichassis Multilink PPP.

signaling

The transmission of Address, Supervision, or other Switching information between stations and Switching Systems, or between Switching Systems, including billing information.

Serial Line Internet Protocol and Point-to-Point Protocol (SL/IP and PPP)

Protocols used to establish real TCP/IP Internet connections over dialup lines, as opposed to leased lines.

Simple Network Management Protocol (SNMP)

Protocol used for monitoring and managing network devices.

software-defined network (SDN)

A switched long-distance service for large users with multiple locations. Instead of putting together their own network, large users can get special usage rates for calls made on regular long-distance company switched long distance services. The service is also know as virtual private network.

SONET

Synchronous Optical Network. Specification for a high-speed (up to 2.5 Gbps) synchronous network developed by Bellcore and designed to run on optical fiber. STS-1 is the basic building block of SONET. See also STS-1.

STS-1

Synchronous Transport Signal level 1. Basic building block signal of SONET, operating at 51.84 Mbps. Faster SONET rates are defined at STS-n, where n is a multiple of 51.84 Mbps. See also SONET.

STS-3c

Synchronous Transport Signal level 3, linked together. SONET format that specifies the frame structure for the 155.52-Mbps lines used to carry ATM cells. See also SONET.

subnet mask

A 32-bit address mask used in IP to indicate the bits of an IP address that are used for the subnet address. Sometimes referred to simply as a mask. See also IP address.

switching

The operations involved in interconnecting circuits in order to establish communications.

switching office (SO)

A telephone company office that contains a switch. Also known as Cenral Office (CO).

synchronous transmission

A method of sending information over a transmission line, and separating discrete characters and symbols by a precise separation in time. Synchronous transmission offers higher throughput because it does not require the start-stop bits used by asynchronous methods. Synchronous transmission is more expensive than other transmission methods.

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T

Terminal Acess Controller Access Control System Plus (TACACS+)

A proprietary Cisco enhancement to Terminal Access Controller Access Control System (TACACS). Provides additional support for authentication, authorization, and accounting. Authentication protocol that provides remote access authentication and related services, such as event logging. User passwords are administered in a central database rather than in individual routers, providing an easily-scalable network security solution.

T-1 (T-1) (T1)

Twenty-four (24) voice channels digitized at 64,000 bps, combined into a single 1. 544-Mbps digital stream (8000-bps signaling), and carried over two pairs of regular copper telephone wires. Used primarily by telephone companies until 1983. Now used for dedicated local access to long distance facilities, long-haul private lines, and for regular local service. Today, most any 1.544 Mbps digital stream is called T-1, regardless of its makeup or transmission medium.

T-3 (T-3) (T3)

Digital WAN carrier facility. T3 transmits DS-3 formatted data or voice at 44.736 Mbps through the telephone switching network using fiber optic cable.

T-carrier (T-1)

A 4-wire digital transmission system which carries a 1.544-Mb/s digital bitstream in each direction. When using one of the framed formats (for example, D4 or ESF), T-1 has 1.536 Mb/s available for user data or digititized voice. Usually channelized into 24 voiceband channels using TDM (24 8-bit PCM samples per 193-bit frame).

TCP/IP

Transmission Control Protocol/Internet Protocol, TCP and IP are two open protocol standards used among computers connected to the Internet, allowing different computer systems and platforms to share data seamlessly. TCP/IP forms the foundation for Internet communications, and provides such services such as Gopher and World Wide Web.

Tellcordia Technologies

Formerly Bellcore. See Bellcore.

TELCO (BOC)

Local telephone company.

telecommunications

The transmission of voice and data through a medium of electrical impulses, and includes all aspects of transmitting information.

telecommunications carrier

Any provider or common carrier of telecommunications services.

telecommunications equipment

Equipment, other than customer premises equipment, used by a carrier to provide telecommunications services, and includes software integral to such equipment (including upgrades).

telecommunications service

The offering of telecommunications, for a fee, directly to the public.

Telnet

A method of connecting from one host computer system to another using the Internet. Telnet allows users to log in to accounts on remote systems, and retrieve text-based information from a remote host.

terminal

A point where information can enter or leave a communications network.

terminal equipment (TE)

Devices and their associated interfaces used to forward information to a local customer or distant terminal.

TFTP

Trivial File Transfer Protocol. Simplified version of FTP that allows files to be transferred between computers over a network.

tip and ring

The two sides of a telephone circuit. The names come from old telephone switch board plugs: the tip wire was connected to the tip of the plug, and the ring wire was connected to the ring at the base of the plug.

topology

Physical arrangement of network nodes and media within an enterprise networking structure.

traffic

Calls being sent and received over a communications network.

transmission (XMISSION) (XMIT)

The electrical transfer of a signal, message, or other form of data from one location to another, with acceptable loss of content due to attenuation, distortion, or noise.

trunk

A communication channel between two Switching Systems.

TTY line

These are asynchronous lines on the router. TTY is a line configuration, not an interface configuration. These lines correspond to async interfaces that are configured separately.

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V

V.120

Dedicated PPP Dial-in.

virtual profiles

Virtual Profiles is a unique Point-to-Point application that can create and configure a virtual access interface dynamically when a dial-in call is received, and tear down the interface dynamically when the call ends.

virtual template

Virutal Templates are used for cloning virtual-access interfaces for inbound calls.

voiceband channel

A transmission channel with a nominal 4 kHz bandwidth, suitable for voice transmission. If sampled at an 8 kHz sampling rate with 8 bit/sample, it becomes a 64 kbit/s data stream.

voice over IP (VoIP)

A technology used to transport voice traffic over the Internet using the existing IP network infrastructure.

VPDN

Virtual Private Dialup Network. The forwarding of PPP links from an Internet Service Provider (ISP) to a home gateway. L2TP and L2F are common options for tunneling protocol.

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W

wide area network (WAN)

An integrated data network linking metropolitan or local networks over common carrier facilities.

World Wide Web (WWW)

The newest and increasingly the most popular service on the Internet, WWW is a "hypertext" information system capable of presenting multimedia information to those with a "direct connection" to the Internet. It requires SL/IP, PPP, or some other dedicated Internet connection and browser software (like Mosaic or Netscape). Users without such a dedicated connection, but who have an online account, can use Lynx, a nongraphical, text-based browser.