6. Cisco IP Phone 7960 Administrator Guide for SIP, Version 1.0

glossary

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A

AAA

Authentication, Authorization, and Accounting. AAA is a suite of network security services that provides the primary framework through which access control can be set up on your Cisco router or access server.

ANI

Automatic number identification.

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C

CAS

Channel associated signaling.

CCAPI

Call control applications programming interface.

CLI

Command line interface.

CO

Central office.

CPE

Customer premises equipment. Terminating equipment, such as terminals, telephones, and modems, supplied by the telephone company, installed at the customer sites, and connected to the telephone company network.

CSM

Call switching module.

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D

dial peer

An addressable call endpoint. In Voice over IP (V0IP), there are two types of dial peers: POTS and VoIP.

DNS

Domain name system used to address translation to convert H.323 IDs, URLs, or e-mail IDs to IP addresses. DNS is also used to assist in the locating remote gatekeepers and to reverse-map raw IP addresses to host names of administrative domains.

DNIS

Dialed number identification service (the called number).

DSP

Digital signal processor.

DTMF

Dual tone multi-frequency.

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E

E.164

The international public telecommunications numbering plan. A standard set by ITU-T which addresses telephone numbers.

E&M

Ear and mouth RBS signaling.

endpoint

An H.323 terminal or gateway. An endpoint can call and be called. It generates and/or terminates the information stream.

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G

gateway

A gateway allows SIP or H.323 terminals to communicate with terminals configured to other protocols by converting protocols. A gateway is the point where a circuit-switched call is encoded and repackaged into IP packets.

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H

H.323

An International Telecommunication Union (ITU-T) standard that describes packet-based video, audio, and data conferencing. H.323 is an umbrella standard that describes the architecture of the conferencing system and refers to a set of other standards (H.245, H.225.0, and Q.931) to describe its actual protocol.

H.323 RAS

Registration, admission, and status. The RAS signaling function performs registration, admissions, bandwidth changes, status and disengage procedures between the VoIP gateway and the gatekeeper.

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I

IVR

Integrated voice response. When someone dials in, IVR responds with a prompt to get a personal identification number (PIN), and so on.

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L

LEC

Local exchange carrier.

Location Server

A SIP redirect or proxy server uses a a location service to get information about a caller's location(s). Location services are offered by location servers.

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M

MF

Multi-frequency tones are made of six frequencies that provide 15 two frequency combinations for indication digits 0-9 and KP/ST signals.

multicast

A process of transmitting PDUs from one source to many destinations. The actual mechanism (that is, IP multicast, multi-unicast, and so forth) for this process might be different for LAN technologies.

multipoint-unicast

A process of transferring PDUs (Protocol Data Units) where an endpoint sends more than one copy of a media stream to different endpoints. This can be necessary in networks which do not support multicast.

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N

node

A H.323 entity that uses RAS to communicate with the gatekeeper, for example, an endpoint such as a terminal, proxy, or gateway.

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P

PDU

Protocol data units used by bridges to transfer connectivity information.

POTS

Plain old telephone service. Basic telephone service supplying standard single line telephones, telephone lines, and access to the PSTN.

Proxy Server

An intermediary program that acts as both a server and a client for the purpose of making requests on behalf of other clients. Requests are serviced internally or by passing them on, possibly after translation, to other servers. A proxy interprets, and, if necessary, rewrites a request message before forwarding it.

PSTN

Public switched telephone network. PSTN refers to the local telephone company.

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R

Redirect Server

A redirect server is a server that accepts a SIP request, maps the address into zero or more new addresses and returns these addresses to the client. It does not initiate its own SIP request nor accept calls.

Registrar

A registrar is a server that accepts REGISTER requests. A registrar is typically co-located with a proxy or redirect server and MAY offer location services.

RAS

Registration, admission, and status protocol. This is the protocol that is used between endpoints and the gatekeeper to perform management functions.

RBS

Robbed bit signaling.

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S

SIP

Session Initiation Protocol. This is a protocol developed by the IETF MMUSIC Working Group as an alternative to H.323. SIP features are compliant with IETF RFC 2543, published in March 1999.

SIP equips platforms to signal the setup of voice and multimedia calls over IP networks.

SPI

Service provider interface.

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T

TDM

Time division multiplexing. Technique in which information from multiple channels can be allocated bandwidth on a single wire based on preassigned time slots. Bandwidth is allocated to each channel regardless of whether the station has data to transmit.

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U

User Agent

See UAS .

UAC

User Agent Client: A user agent client is a client application that initiates the SIP request.

UAS

User Agent Server (or user agent): A user agent server is a server application that contacts the user when a SIP request is received, then returns a response on behalf of the user. The response accepts, rejects or redirects the request.

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V

VoIP

Voice over IP. The ability to carry normal telephone-style voice over an IP-based Internet with POTs-like functionality, reliability, and voice quality. VoIP is a blanket term, which generally refers to Cisco's standards based (for example H.323) approach to IP voice traffic.