AAA authentication, authorization, and accounting.
The network security services that provide the primary framework
through which you set up access control on your router or access
address resolution Generally, a method for resolving
differences between computer addressing schemes. Address resolution
usually specifies a method for mapping network layer (Layer 3) addresses
to data link layer (Layer 2) addresses.
agent An object or application that can be a server, a client, or
ASCII American Standard Code for Information Interchange.
8-bit code for character representation (7 bits plus parity).
ATA Analogue Terminal Adapters (ATA) are hardware
devices that act as a Gateway between analogue devices (regular
headphones, cordless phones, or fax machines) and any IP interface,
implementing VoIP protocols such as SIP or H.323.
BRA Basic Rate Access of ISDN; it implements two
64 kbps B channels + one 16 kbps D channel (2B+D), carrying user
traffic and signaling information respectively to the user via twisted
pair local loop.
call Establishment of (or attempt to establish)
a voice or data connection between two endpoints, or between two
points which provide a partial link (e.g. a trunk) between two endpoints.
CAS Channel Associated Signaling. In E1 applications,
timeslot 16 is used to transmit CAS information.
CDR Call Record Detail. A term used to describe
log records for calling services. This includes such information
as where the call originated, what the start time was, who the call
was made to, what time the call ended, etc.
CO central office. A local switching system that connects
lines to lines and lines to trunks. Sometimes used to refer to the
building in which a switching system is located and the associated
equipment. Also the physical point where calls enter the long distance
network. Sometimes referred to as Class 5 office, end office, or
Local Dial Office.
Codec Coder-Decoder. Transforms analog voice into
digital bit stream and vice-versa.
DAL Dedicated Access Line. An analog special-access
line that runs from a caller's own equipment directly to a long
distance company's switch or POP. Usually provided by a local telephone
company. The line may go through the local telco central office,
but the local telco does not switch calls on this line.
DHCP Dynamic Host Control Protocol. A protocol
that is used to dynamically allocate and assign IP addresses. DHCP
allows you to move network devices from one subnet to another without
administrative attention. RFC 2131 and RFC 2132.
dial peer An addressable call endpoint. In Voice over IP (VoIP),
there are two types of dial peers: POTS and VoIP.
dial plan A description of the dialing arrangements
for customer use on a network.
DID Direct Inward Dialing
DNS Domain Name System. System used in the Internet
for translating names of network nodes into addresses.
DSL Digital Subscriber Line. Public network technology
that delivers high bandwidth over conventional copper wiring at
limited distances. There are four types of DSL: ADSL, HDSL, SDSL,
and VDSL. All are provisioned via modem pairs, with one modem located
at a central office and the other at the customer site. Because
most DSL technologies do not use the whole bandwidth of the twisted
pair, there is room remaining for a voice channel.
DTMF Dual Tone Multi Frequency: The paired, high- and low-frequency
tones which make up touch tone dialing.
E.164 ITU-T recommendation for international telecommunication
numbering, especially in ISDN, BISDN, and SMDS. An evolution of
standard telephone numbers.
E1 Wide-area digital transmission scheme. E1 is
the European equivalent of a T1 line. The E1's higher clock rate
(2.048 MHz) allows for 32 64 Kbps channels, which include one channel
for framing and one channel for D-channel information.
end point SIP or H.323 terminal or gateway. An
endpoint can call and be called. It generates and terminates the
FCP Firewall Communication Protocol connects signaling
servers such as SIP Proxies or H.323 gatekeepers with firewalls,
NATs and possibly other intermediate network devices ("middleboxes").
G.711 64 kbos PCM half-duplex codec (high quality,
high bandwidth, minimum processor load).
G.723.1 6,4/5,3 kbps MP-MLQ codec (low quality,
low bandwith, high processor load due to the high compression rate).
G.729 An ITU-T algorithm for voice encoding that
produces an 80-bit voice sample every 10 msec (bit rate of 8 kbps).
The codec works in blocks of 10 msec and so it is possible to generate
frames of multiple 10 msec duration. Implements medium quality,
suitable for low bandwidth, while it requires high processor load.
Gateway The server that connects the VoIP network
with PBXs and PSTN devices.
H.323 Recommendation from the ITU that sets standards
for multimedia communications over IP networks. It also addresses
call control, multimedia management, and bandwidth management.
HTTP Hypertext Transfer Protocol. The protocol
used by Web browsers and Web servers to transfer files, such as
text and graphic files.
HTTP digest A password-based authentication method
supported by LDAP servers.
ICMP Internet Control Message Protocol. A network-layer
Internet protocol that reports errors and provides other information
relevant to IP packet processing. RFC792.
IE Information element.
IETF Internet Engineering Task Force. Task force
consisting of over 80 working groups responsible for developing
Internet standards. The IETF operates under the auspices of ISOC.
IMAP Internet Message Access Protocol. A UNIX server
protocol allowing users to scan message headers, download selected
messages, and administer e-mail folders.
IP Internet Protocol. A network-layer protocol
in the TCP/IP stack that offers a connectionless internetwork service.
IP provides features for addressing, type-of-service (ToS) specification,
fragmentation and reassembly, and security. RFC791.
IPSec IP Security. An IETF standard that is used
to provide security for transmission of sensitive information over
unprotected networks such as the Internet. IPSec acts at the network
layer, protecting and authenticating IP packets between participating
IPSec devices (“peers”), such as Cisco routers.
ISDN Integrated Services Digital Network. A communications
protocol, offered by telephone companies, that permits telephone
networks to carry data, voice, and other traffic.
ISP Internet Service Provider. Company that provides
Internet access to other companies and individuals.
ITU International Telecommunications Union. Established
by the United Nations, with membership from virtually every world
government. Three primary goals are: defining and adopting telecommunications
standards; regulating use of the radio frequency spectrum; and furthering
world-wide telecommunications development.
IVR Integrated voice response. Consists of simple
voice prompting and digit collection to authenticate user and identify
LDAP Lightweight Directory Access Protocol. An
emerging software protocol for enabling anyone to locate organizations,
individuals, and other resources such as files and devices in a
network, whether on the Internet or on a corporate intranet. LDAP
is a “lightweight” (smaller amount of code) version
of DAP (Directory Access Protocol), which is part of X.500, a standard
for directory services in a network.
LEC Local Exchange Carrier. Local or regional telephone
company that owns and operates a telephone network and the customer
lines that connect to it.
location server A device that processes requests (typically from
a redirect or proxy server) to provide information about the possible
location of a target end user.
MGC Media gateway controller. A device that provides
control of media and signalling gateways.
MGCP Media Gateway Control Protocol. Protocol that
helps bridge the gap between circuit-switched and IP networks. A
combination of Internet Protocol Device Control (IPDC) and Simple
Gateway Control Protocol (SGCP). MGCP allows external control and
management of data communications devices, or “media gateways”
at the edge of multiservice packet networks by software programs.
MIB Management Information Base - A directory of
logical names of information resources residing in a network and
pertaining to the network's management.
MIME Multipurpose Internet Mail Extension. A set
of extensions to the SMTP message syntax allowing various file types
to be attached to text mail.
Mu-Law The PCM voice coding and companding standard
used in Japan and North America. A PCM algorithm yielding a raw
64-kbps transmission rate.
name mapping Generally, the process of associating
a name with a network location.
NAT Network Address Translation protocol. Mechanism
for reducing the need for globally unique IP addresses. NAT allows
an organization with addresses that are not globally unique to connect
to the Internet by translating those addresses into globally routable
address space. Also known as Network Address Translator.
NTP Network Time Protocol. The recommended protocol
for synchronizing the time of hosts in the uOne network.
PABXI Private Automatic Branch Exchange. Telephone
switch for use inside a corporation. PABX is the preferred term
in Europe, whereas PBX is used in the United States.
PBX Private Branch Exchange. Privately-owned central
PCM Pulse Code Modulation. The form of modulation
in which the information signals are sampled at regular intervals
and a series of pulses in coded form are transmitted representing
the amplitude of the information signal at that time. For T1 applications,
a method of converting successive (every 125 us) analog samples
of a voice waveform to successive 8-bit codes, to be transmitted
in an 8-bit timeslot of a T1 frame. In “robbed bit”
frames, only the most significant 7 bits are used to encode the
sample. The total bit rate for such a channel is (8000 samples/sec)
x (8-bits/sample) = 64000 bits/sec.
POTS Plain Old Telephone Service. Basic telephone
service supplying standard single line telephones, telephone lines,
and access to the Public Switched Telephone Network.
PRA Primary Rate Access. A Canadian term synonymous
with ISDN PRI.
PRI Primary Rate Interface. PRI is an ISDN interface
to primary rate access. Primary rate access consists of a single
64 Kbps D channel plus 23 T1 or 30 E1 B channels for voice or data.
proxy server An intermediate device that receives
SIP requests from a client and then initiates requests on the client’s
PSTN Public Switched Telephone Network. PSTN refers
to the local telephone company.
Q.931 Call signaling protocol for setup and termination
Q.SIG Q Signaling. An inter-PBX signaling protocol
for networking PBX supplementary services in a multi- or uni-vendor
RADIUS Remote Authentication Dial-In User Service.
An authentication and accounting system used by many Internet Service
RAS Registration, Admission, Status. Protocol used
in the H.323 protocol suite for discovering and interacting with
redirect server A device that receives SIP requests, strips
out the address in the request, checks its address tables for any
other addresses that may be mapped to the one in the request, and
then returns the results of the address mapping to the client.
registrar server A device that processes requests
from UACs for registration of their current location. Registrar
servers are often co-located with a redirect or proxy server.
RFC Request For Comments. Document series used
as the primary means for communicating information about the Internet.
Some RFCs are designated by the IAB as Internet standards. Most
RFCs document protocol specifications such as Telnet and FTP, but
some are humorous or historical. RFCs are available online from
RPC Remote Procedure Call. An external form of
communication that allows objects to communicate with each other
over the network. The RPC programming interface is built into each
server's Client and Server subsystems to provide external communication
RSVP IETF specification that allows applications to request
RTP/RTCP Real-time Transfer Protocol/RTP Control Protocol. An IETF
specification for audio and video signaling management. Allows applications
to synchronize and spoil audio and video information.
RTSP Real Time Streaming Protocol. Proposed standard
for controlling streaming data over the World Wide Web.
SAP Session Announcement Protocol. A protocol
used to assist in the advertisement of multicast multimedia conferences
and other multicast sessions, and to communicate the relevant session
setup information to prospective participants.
SDP Session Description Protocol. A protocol used
to describe the characteristics of multimedia sessions for the purposes
of session announcement, session invitation, and other forms of
multimedia session initiation. RCS 2327.
signaling Process of sending a transmission signal over a physical
medium for purposes of communication.
SIMPLE SIP for Instant Messaging and Presence Leveraging
Extension (IETF working group).
SIP Session Initiation Protocol. Offers many of
the same architectural features as H.323, but relies on IP-specific
technologies, such as DNS (RFC 2543, RFC 3261). It also incorporates
the concept of fixed port numbers for all devices and allows for
the use of proxy servers.
SNMP Simple Network Management Protocol. The Internet
standard protocol developed to manage nodes on an IP network.
SS7 Signaling System 7. The protocol used to communicate
between components of the AIN. The SS7 protocol is used to set up
and tear down phone calls as well as to enable “intelligent”
services. The SS7 network is a physically separate network from
the phone network used to transmit voice data.
STUN Simple Traversal of UDP through NAT is a lightweight
protocol that allows applications to discover the presence and types
of NATs and firewalls between them and the public Internet. It also
provides the ability for applications to determine the public Internet
Protocol (IP) addresses allocated to them by the NAT.(RFC 3489).
T1 Digital WAN carrier facility. T1 transmits
DS-1 formatted data at 1.544 Mbps through the telephone-switching
network, using AMI or B8ZS coding. T1 is the North American equivalent
of an E1 line.
TCL Tool command language.
TCP Transmission Control Protocol. Connection-oriented
transport layer protocol that provides reliable full-duplex data
transmission. TCP is part of the TCP/IP protocol stack.
TFTP Trivial File Transfer Protocol. Allows files
to be transferred from one computer to another over a network.
UA User Agent. See UAC and UAS.
UAC User Agent Client. In SIP, a client application
that initiates the SIP request.
UAS User Agent Server. In SIP, 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.
UCS Unified call services.
UDP A connectionless transport layer protocol in
the TCP/IP protocol stack. UDP is a simple protocol that exchanges
datagrams without acknowledgments or guaranteed delivery, requiring
that error processing and retransmission be handled by other protocols.
URL Uniform Resource Locator. An identifier used
to locate content that is transported via the HTTP protocol.
VFC Voice feature card.
VNM Voice network module.
VoIP Voice over IP. The ability to carry normal
telephony-style voice over an IP-based internet with POTS-like functionality,
reliability, and voice quality.