Cisco AS5850 Universal Gateway Operations, Administration, Maintenance, and Provisioning Guide - Glossary [Cisco AS5800 Series Universal Gateways]

Table Of Contents

Glossary

A

AAA

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

access charge

Charges that 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 networks. Accounting management subsystems are responsible for collecting network data relating to resource usage. Related management topics are 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

Traffic director 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.OL-0552-03advertising

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. Notification that a threshold (rising or falling) established by the user has been met. See also event and trap.

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, such as voltage, which reflects variations in some quantity. An example is the 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) dial-in 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 using 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.

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 (for example, 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 thirty 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 (Telcordia Technologies)

Bell Communications Research. Organization that performs research and development on behalf of the regional Bell operating companies (RBOCs).

Broadband Integrated Services Digital Network

BISDN is 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 in digital language. Depending on how the bits within them are ordered, these bytes can be translated into numbers, words, or commands.

bits per second (bps)

Unit used to refer to transmission speeds of sending data (for example, 2400 bps, 14,400 bps, etc.). Speed takes on particular importance when using online Internet services. See also kbps.

Basic Rate Interface (BRI)

BRI is an ISDN scheme 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. See address.

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 other information.

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 (for example, a trunk) between two endpoints.

capture group (RMON 2)

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

carrier

A long-distance company that 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.

CAS

Channel-associated signaling.

CCITT

(Comitre Consultatif Internationale de Telegraphique et Telephonique) 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 the 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. See also switching office (SO).

Challenge Handshake Authentication Protocol (CHAP)

Security feature supported on lines using PPP encapsulation that prevents unauthorized access. CHAP does not itself prevent unauthorized access, it merely identifies the remote end. The router or access server then determines whether that user is allowed access. Compare to PAP.

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.

client

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

client/server

A distributed computing architecture in which numerous dispersed terminals, each having 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 TV installation. Being replaced by fiber optic cable of greater capacity and bandwidth.

command-line interface (CLI)

Text-based interface as opposed to a graphic user interface (GUI). The basic Cisco IOS configuration and management interface.

common carrier

An entity that provides a public communications conduit regardless of 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 initiate corrective action.

Configuration Manager

A TrafficDirector application that allows you to add and configure agents, agent groups, switches, and Frame Relay agents. 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 its pool subranges. The condition is that the start of a pool subrange must coincide with the start of a modem module, and the end of a pool subrange must coincide with the end of a modem module.

constraint-capable modem pool

A constraint-free modem pool that has its pool subranges specified so 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 subranges. A modem pool is created by default to be constraint-free.

customer premises equipment (CPE)

Equipment deployed on premises (other than a carrier) to originate, route, or terminate telecommunications.

D

D-channel (ISDN)

The 24th time slot on T1/PRI, or the 16th time slot on E1/PRI, and used for signaling information. Call setup and teardown information is sent over the D channel.

default firmware

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

demodulation (MOD)

The process of retrieving data from a modulated signal.

dial interfaces

The interfaces used for terminating digital calls. 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 reception of address digits using onhook and offhook transitions of the DC signaling variable.

dial selective signaling

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 can provide phone services that allow customers 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, and so on) 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-kbps or 64-kbps 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.

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

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.

e-mail

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 terminate telephone toll services.

F

faceplate

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

Federal Communications Commission (FCC)

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 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-optic 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 modulated 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). See also TFTP.

firmware list

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

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.

GigE

Gigabit Ethernet. Data transmission of 1000 Mbps.

H

host

On the Internet, a host, or host computer, can serve as both waystation 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 who are capable of logging in through a particular account. A computer system on a network. A host is similar to a node, except that host usually implies a computer system, whereas node generally applies to any networked system, including access servers and routers. See also 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, users 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.

I

information service

The offering for generating, acquiring, storing, transforming, processing, retrieving, utilizing, or making available information using telecommunications. This service includes electronic publishing, but does not include management, control, or operation on 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 other computer 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 are used together 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

A range of IP addresses set aside for a specific allocation purpose, such as DHCP. As clients connect to a network gateway, 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 wire. 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 is 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.

L

local area network (LAN)

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

leased line

A dedicated telephone line for whatever purpose is designated by the lessee. Leased lines are capable of higher transmission speeds for data communications than are 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 viewpoint, the transmission path between a customer's 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

During configuration of 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

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.

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.

modem

The term is short for modulator/demodulator. 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.

modem pool

A modem pool covers a specified range of modems that accept calls based on the number called by dial-in 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 SPE firmware upgrades.

modulation

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

Multilink PPP (MLP)

Method of splitting, recombining, and sequencing datagrams across multiple logical data links.

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.

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. Includes subscriber numbers, databases, signaling systems, and information sufficient for billing and collection. Also used in the transmission, routing, or other provision of a telecommunications service.

network management system (NMS)

System responsible for managing at least part of a network. An NMS is generally a reasonably powerful and well-equipped computer such as an engineering workstation. NMSs communicate with agents to help keep track of network statistics and resources.

network trunks

Circuits connecting switching centers.

NextPort card

Obsolete term. API used by SPEs, SPE firmware, and Cisco IOS software to support modem connections or other services. See universal port card.

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.

O

offline

The absence of connection to another computer. In an offline 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 SPE firmware that is indicated as the alternate firmware image to which the modem module is to be upgraded.

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. Asynchronous Transfer Mode (ATM), a standard for switching data of various types over private and public networks, specifies a packet of uniform 53-byte length.

Password Authentication Protocol (PAP)

Authentication protocol that allows PPP peers to authenticate one another. The remote router attempting to connect to the local router is required to send an authentication request. Unlike CHAP, PAP passes the password and host name or username in the clear (unencrypted). PAP does not itself prevent unauthorized access, but merely identifies the remote end. The router or access server then determines if that user is allowed access. PAP is supported only on PPP lines. Compare with CHAP.

power entry module (PEM)

Module on the back of the Cisco AS5850 through which power is supplied.

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 interexchange carrier establishes itself for the purpose of obtaining LATA access, and to which the regional operating company provides access services.

point-to-point

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

Point-to-Point Protocol (PPP)

Protocol that provides router-to-router and host-to-network connections over synchronous and asynchronous circuits. PPP was designed to work with several network layer protocols, such as IP, IPX, and ARA. PPP also has built-in security mechanisms, such as CHAP and PAP. PPP relies on two protocols: LCP and NCP.

pool subrange

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

port

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

PSTN

Public switched telephone network. 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. Examples of protocols are Ethernet, IEEE 802.5 token ring, X Modem, and Kermit.

Q

quality of service (QoS)

A contracted data rate that is negotiated between two ATM endpoints 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.

R

regional Bell operating company (RBOC)

One of several 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.

route switch controller (RSC) card

The main processor card in a Cisco AS5850. Provides the following functions: transfers data as Fast Ethernet or Gigabit Ethernet packets; boots and reloads software images; provides source clocks used by all server cards and power supplies; extracts an external reference clock from an external E1 or T1 signal; and connects to an external alarm source.

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.

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)

A protocol 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 or Point-to-Point Protocol (SLIP or PPP)

Protocols for establishing TCP/IP Internet connections over dial-up lines, as opposed to leased lines.

Simple Network Management Protocol (SNMP)

A protocol 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. Also known as Virtual Private Network (VPN).

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.

Synchronous Transport Signal level 1 (STS-1)

STS-1 is the 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.

Synchronous Transport Signal level 3 (STS-3c)

STS-3c concatenated or 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 being 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. See also central 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 high throughput because it does not require the start-stop bits used by asynchronous methods. Synchronous transmission is more expensive than other transmission methods.

T

TACACS+

Terminal Access Controller Access Control System Plus. Proprietary Cisco enhancement to Terminal Access Controller Access Control System. 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 solution to network security.

T-1 (T-1) (T1)

Twenty-four (24) voice channels digitized at 64,000 bps, combined into a single 1.544-Mbps digital stream (8,000 bps signaling), and carried over two pairs of regular copper wire. Used primarily by telephone companies until 1983. Now used for dedicated local access to long-distance facilities, long-haul private lines, and regular local service. Today, almost 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. Transmits DS-3 formatted data or voice at 44.736 Mbps through the telephone switching network using fiber optic or coaxial cable.

T-carrier (T-1)

A four-wire digital transmission system that carries in each direction. A 1.544-Mbps digital bitstream. When using one of the framed formats (such as D4 or ESF), a T1 line has 1.536 Mbps available for user data or digitized 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. 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 as Gopher and World Wide Web.

Telcordia Technologies

Formerly Bellcore. See Bellcore.

telco (BOC)

Local telephone company. Formerly Bell operating company.

telecommunications

The transmission of voice and data through a medium of electrical impulses. 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. 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. 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. See also File Transfer Protocol (FTP).

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

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

U

universal port card (UPC)

API used by SPEs, SPE firmware, and Cisco IOS software to support modem connections or other services. Replaces the NextPort card.

V

V.120

Dedicated PPP dial-in.

Virtual Profiles

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

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 bits per sample, it becomes a 64-kbps 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 to a home gateway. L2TP and L2F are common options for tunneling protocol.

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 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 SLIP, 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.

	Cisco AS5850 Universal Gateway Operations, Administration, Maintenance, and Provisioning Guide
	Glossary
Cisco AS5850 Universal Gateway Operations, Administration, Maintenance, and Provisioning Guide Preface Chap 1: Overview Chap 2: Operations Chap 3: Administration Chap 4: Maintenance Chap 5: Provisioning Appendix A: Advanced Quick Reference Glossary	Download this chapter Glossary Download the complete book Book-length pdf (PDF - 2 MB) Feedback Table Of Contents Glossary A AAA Triple-A security in billing stands for authentication, authorization and accounting. access charge Charges that 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 networks. Accounting management subsystems are responsible for collecting network data relating to resource usage. Related management topics are 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 Traffic director 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.OL-0552-03advertising 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. Notification that a threshold (rising or falling) established by the user has been met. See also event and trap. 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, such as voltage, which reflects variations in some quantity. An example is the 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) dial-in 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 using 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. 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 (for example, 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 thirty 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 (Telcordia Technologies) Bell Communications Research. Organization that performs research and development on behalf of the regional Bell operating companies (RBOCs). Broadband Integrated Services Digital Network BISDN is 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 in digital language. Depending on how the bits within them are ordered, these bytes can be translated into numbers, words, or commands. bits per second (bps) Unit used to refer to transmission speeds of sending data (for example, 2400 bps, 14,400 bps, etc.). Speed takes on particular importance when using online Internet services. See also kbps. Basic Rate Interface (BRI) BRI is an ISDN scheme 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. See address. 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 other information. 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 (for example, a trunk) between two endpoints. capture group (RMON 2) Storage of packets, based on filters, for later retrieval. carrier A long-distance company that 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. CAS Channel-associated signaling. CCITT (Comitre Consultatif Internationale de Telegraphique et Telephonique) 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 the 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. See also switching office (SO). Challenge Handshake Authentication Protocol (CHAP) Security feature supported on lines using PPP encapsulation that prevents unauthorized access. CHAP does not itself prevent unauthorized access, it merely identifies the remote end. The router or access server then determines whether that user is allowed access. Compare to PAP. 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. client End-user computer on a network (local or Internet). client/server A distributed computing architecture in which numerous dispersed terminals, each having 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 TV installation. Being replaced by fiber optic cable of greater capacity and bandwidth. command-line interface (CLI) Text-based interface as opposed to a graphic user interface (GUI). The basic Cisco IOS configuration and management interface. common carrier An entity that provides a public communications conduit regardless of 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 initiate corrective action. Configuration Manager A TrafficDirector application that allows you to add and configure agents, agent groups, switches, and Frame Relay agents. 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 its pool subranges. The condition is that the start of a pool subrange must coincide with the start of a modem module, and the end of a pool subrange must coincide with the end of a modem module. constraint-capable modem pool A constraint-free modem pool that has its pool subranges specified so 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 subranges. A modem pool is created by default to be constraint-free. customer premises equipment (CPE) Equipment deployed on premises (other than a carrier) to originate, route, or terminate telecommunications. D D-channel (ISDN) The 24th time slot on T1/PRI, or the 16th time slot on E1/PRI, and used for signaling information. Call setup and teardown information is sent over the D channel. default firmware The SPE firmware in a firmware list that is loaded on the modem modules in the absence of any SPE firmware-related configuration commands. This is always the first firmware image in the firmware list. demodulation (MOD) The process of retrieving data from a modulated signal. dial interfaces The interfaces used for terminating digital calls. 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 reception of address digits using onhook and offhook transitions of the DC signaling variable. dial selective signaling 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 can provide phone services that allow customers 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, and so on) 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-kbps or 64-kbps 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. 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 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. e-mail 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 terminate telephone toll services. F faceplate The front panel of a plug-in module such as a line card or power supply. Federal Communications Commission (FCC) 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 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-optic 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 modulated 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). See also TFTP. firmware list The list of available bundled SPE firmware images in the modem card image running in a particular modem slot. 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. GigE Gigabit Ethernet. Data transmission of 1000 Mbps. H host On the Internet, a host, or host computer, can serve as both waystation 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 who are capable of logging in through a particular account. A computer system on a network. A host is similar to a node, except that host usually implies a computer system, whereas node generally applies to any networked system, including access servers and routers. See also 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, users 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. I information service The offering for generating, acquiring, storing, transforming, processing, retrieving, utilizing, or making available information using telecommunications. This service includes electronic publishing, but does not include management, control, or operation on 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 other computer 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 are used together 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 A range of IP addresses set aside for a specific allocation purpose, such as DHCP. As clients connect to a network gateway, 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 wire. 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 is 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. L local area network (LAN) A limited distance network connecting a defined set of terminals such as workstations within an office, offices in a building, or buildings within a campus. leased line A dedicated telephone line for whatever purpose is designated by the lessee. Leased lines are capable of higher transmission speeds for data communications than are 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 viewpoint, the transmission path between a customer's 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 During configuration of 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 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. 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. modem The term is short for modulator/demodulator. 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. modem pool A modem pool covers a specified range of modems that accept calls based on the number called by dial-in 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 SPE firmware upgrades. modulation Alterations in the characteristics of carrier waves. Usually impressed on the amplitude and the frequency. Multilink PPP (MLP) Method of splitting, recombining, and sequencing datagrams across multiple logical data links. 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. 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. Includes subscriber numbers, databases, signaling systems, and information sufficient for billing and collection. Also used in the transmission, routing, or other provision of a telecommunications service. network management system (NMS) System responsible for managing at least part of a network. An NMS is generally a reasonably powerful and well-equipped computer such as an engineering workstation. NMSs communicate with agents to help keep track of network statistics and resources. network trunks Circuits connecting switching centers. NextPort card Obsolete term. API used by SPEs, SPE firmware, and Cisco IOS software to support modem connections or other services. See universal port card. 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. O offline The absence of connection to another computer. In an offline 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 SPE firmware that is indicated as the alternate firmware image to which the modem module is to be upgraded. 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. Asynchronous Transfer Mode (ATM), a standard for switching data of various types over private and public networks, specifies a packet of uniform 53-byte length. Password Authentication Protocol (PAP) Authentication protocol that allows PPP peers to authenticate one another. The remote router attempting to connect to the local router is required to send an authentication request. Unlike CHAP, PAP passes the password and host name or username in the clear (unencrypted). PAP does not itself prevent unauthorized access, but merely identifies the remote end. The router or access server then determines if that user is allowed access. PAP is supported only on PPP lines. Compare with CHAP. power entry module (PEM) Module on the back of the Cisco AS5850 through which power is supplied. 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 interexchange carrier establishes itself for the purpose of obtaining LATA access, and to which the regional operating company provides access services. point-to-point A communications circuit between two terminations that does not connect with a public telephone system. Point-to-Point Protocol (PPP) Protocol that provides router-to-router and host-to-network connections over synchronous and asynchronous circuits. PPP was designed to work with several network layer protocols, such as IP, IPX, and ARA. PPP also has built-in security mechanisms, such as CHAP and PAP. PPP relies on two protocols: LCP and NCP. pool subrange A contiguous range of modems. The pool-range set for a modem pool is the logical union of a set of pool subranges. port Entrance or access point to a computer, multiplexor device, or network where signals can be supplied, extracted, or observed. PSTN Public switched telephone network. 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. Examples of protocols are Ethernet, IEEE 802.5 token ring, X Modem, and Kermit. Q quality of service (QoS) A contracted data rate that is negotiated between two ATM endpoints 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. R regional Bell operating company (RBOC) One of several 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. route switch controller (RSC) card The main processor card in a Cisco AS5850. Provides the following functions: transfers data as Fast Ethernet or Gigabit Ethernet packets; boots and reloads software images; provides source clocks used by all server cards and power supplies; extracts an external reference clock from an external E1 or T1 signal; and connects to an external alarm source. 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. 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) A protocol 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 or Point-to-Point Protocol (SLIP or PPP) Protocols for establishing TCP/IP Internet connections over dial-up lines, as opposed to leased lines. Simple Network Management Protocol (SNMP) A protocol 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. Also known as Virtual Private Network (VPN). 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. Synchronous Transport Signal level 1 (STS-1) STS-1 is the 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. Synchronous Transport Signal level 3 (STS-3c) STS-3c concatenated or 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 being 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. See also central 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 high throughput because it does not require the start-stop bits used by asynchronous methods. Synchronous transmission is more expensive than other transmission methods. T TACACS+ Terminal Access Controller Access Control System Plus. Proprietary Cisco enhancement to Terminal Access Controller Access Control System. 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 solution to network security. T-1 (T-1) (T1) Twenty-four (24) voice channels digitized at 64,000 bps, combined into a single 1.544-Mbps digital stream (8,000 bps signaling), and carried over two pairs of regular copper wire. Used primarily by telephone companies until 1983. Now used for dedicated local access to long-distance facilities, long-haul private lines, and regular local service. Today, almost 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. Transmits DS-3 formatted data or voice at 44.736 Mbps through the telephone switching network using fiber optic or coaxial cable. T-carrier (T-1) A four-wire digital transmission system that carries in each direction. A 1.544-Mbps digital bitstream. When using one of the framed formats (such as D4 or ESF), a T1 line has 1.536 Mbps available for user data or digitized 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. 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 as Gopher and World Wide Web. Telcordia Technologies Formerly Bellcore. See Bellcore. telco (BOC) Local telephone company. Formerly Bell operating company. telecommunications The transmission of voice and data through a medium of electrical impulses. 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. 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. 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. See also File Transfer Protocol (FTP). 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 Asynchronous lines on a router. TTY is a line configuration, not an interface configuration. These lines correspond to async interfaces that are configured separately. U universal port card (UPC) API used by SPEs, SPE firmware, and Cisco IOS software to support modem connections or other services. Replaces the NextPort card. V V.120 Dedicated PPP dial-in. Virtual Profiles 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 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 bits per sample, it becomes a 64-kbps 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 to a home gateway. L2TP and L2F are common options for tunneling protocol. 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 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 SLIP, 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.
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