Glossary: Glossary

3GPP
Third Generation Partneship Project (ETSI)
AAA
Authentication, Authorization, Accounting
ABNF
Augmented Backus-Naur Form
ADSL
Asymmetric Digital Subscriber Line
AGC
Automatic Gain Control
ALG
Application Level Gateway
B2BUA
Back to Back User Agent. See also the definition by wikipedia.
Codec
Algorithm used to encode and decode multi-media data (voice, vide) in format suitable for transport in the Internet. See also: G.711, PCM
G.723.1
6.4/5.3 kbps MP-MLQ codec (low quality, low bandwidth, high processor load due to the compression)
G.726
40/32/24/16 ADPCM codec (good quality, medium bandwidth, low processor load)
G.728
16 kbps LD-CELP codec (medium quality, medium bandwidth, very high processor load)
G.729
8 kbps ACELP codec (medium quality, low bandwidth, high processor load)
GSM
Global System for Mobile communications
iLBC
internet Low Bitrate Codec
CPL
Call Processing Language, an XML based language that can be used to describe and control processing of calls in VoIP systems.
CPS
Calls Per Second
DIAMETER
IETF protocol that can be used for authentication, authorization, and accounting purposes. Successor of RADIUS. See also: RADIUS
DND
Do Not Disturb
DTMF
Dual Tone Multi-Frequency encoding of numbers. See also: VoIP
ETSI
European Telecommunications Standards Institute
G.711
64 kbps PCM half-duplex codec (high quality, high bandwidth, minimum CPU load) See also: Codec
GLP
Gateway Location Protocol
ICMP
Internet Control Message Protocol.
IEEE
Institute of Electrical and Electronic Engineers
IETF
Internet Engineering Task Force, the Internet standards body. See also: IAB, IANA, IESG, SIMPLE, SIPPING
BOF
Birds of a Feather. The term for IETF interest groups.
IAB
Internet Architecture Board, a group of people overseeing the technical aspects of the IETF/IESG See also: IANA, IESG, IETF
IANA
Internet Assigned Number Authority See also: IAB, IESG, IETF
IESG
Internet Engineering Steering Group See also: IAB, IANA, IETF
SIMPLE
Extensions of SIP for Instant Messaging and Presence, also a working group name in the IETF See also: IETF, SIP-related
SIPPING
Session Initiation Protocol Project Investigation, an IETF working group. See also: IETF
IMPP
Instant Messaging and Presence Protocol
IMS
IP Multimedia System
C-BGF
Core Border Gateway Function. (More description needed).
HSS
Home Subscriber Server. This is the server containing database of subscriber related data. See also: AUC, HLR
AUC
Authentication Center. (More description needed). See also: HSS
HLR
Home Location Register. (More accurate description needed). See also: HSS
I-BCF
Interconnect Border Control Function. (Do you know more ? Then please add more accurate description).
I-BGF
Interconnect Border Gateway Function. (More description needed).
I-CSCF
Interrogating Call Session Control Function. This is the element in the home network that determines the S-CSCF the UE should talk to. This is achieved by querying the Home Subscriber Server (HSS).
P-CSCF
The Proxy Call Session Control Function. This is the SIP proxy that UE will contact. This element can be either in home or in visited network. This element ensures that messages from UE are passed to correct home network of the UE.
S-CSCF
Serving Call Session Control Function. This is the element in the home network that registers users and provides services to them.
IPT
Internet Protocol Telephony
ISDN
Integrated Services Digital Network
ISP
Internet Service Provider
ITSP
Internet Telephony Service Provider
ITU
International Telecommunication Union
IVR
Interactive Voice Response
JTAPI
Java Telephony API
LDAP
Lightweight Directory Access Protocol
MGCP
Media Gateway Control Protocol
NAPT
Network Address and Port Translation See also: NAT
NAT
Network Address Translator See also: NAPT
PBX
Packet Branch Exchange
PCM
Pulse Code Modulation See also: Codec
POTS
Plain Old Telephone System
PSTN
Public Switched Telephone Network
PTT
Push To Talk
RADIUS
IETF protocol for authentication, authorization, and accounting. See also: DIAMETER
repository
A code repository system like CVS and subversion is a central storage where all code and all versions are kept. iptel.org projects use both CVS and subversion. See http://en.wikipedia.org/wiki/Version_control_system
branch
A term used in code repositories to describe a separate code tree that was branched out from the main development tree (trunk) and is maintained separately. Typically, in preparation for a new code release, a release branch is created. The main tree (trunk) can thus be used to introduce new code without affecting the release. The release branch is later used for creating bug fix releases.
head
The head of a given branch is (technically) the latest checked in version of the code (and not an earlier revision/version). However, the term head is sometimes also used interchangably with trunk.
tag
A tag is readable name for a given revision/version of a repository trunk or branch. Normally a tag is created when you want to have an easy to remember name for the code as it is at a given point. This means that you later can easily checkout the code using the tag and get the exactly like it was at the time you created the tag. See also: branching
trunk
The main development where all new changes are added and where developers do their stuff is referred to as the trunk.
RSVP
Resource Reservation Setup Protocol
RTP
Real-time Transport Protocol, an IETF protocol that can be used to carry multi-media data over the Internet. See also: RTCP
RTCP
Real-time Transport Control Protocol See also: RTP
RTSP
Real Time Streaming Protocol
SRTP
Secure Real-time Transport Protocol
RTPproxy
Real-time Transport Protocol proxy server.
S/MIME
Secure Multipurpose Internet Mail Extensions
SCTP
Stream control Transmission Protocol, a transport protocol designed specificaly for signalling.
SDP
Session Description Protocol, simple plain text document (usually in the body of SIP messages) that describes the capability of an internet end point.
SEMS
SIP Express Media Server: flexible framework for media-oriented applications.
SER
SIP Express Router, fast and flexible SIP server.
SERctl
The cmd-line tools for administrators of SER based SIP servers.
SERweb
The WWW interface for administrators of SER based SIP servers.
SIP-related
Session Initiation Protocol related terms. See also: SIMPLE
branching
A proxy server can send each SIP request to multiple destinations (either using forking or sending the request sequentially). Each downstream SIP request is sent on its own branch (which is represented by its own UAC in the proxy server). See also: tag, UAC
CSeq
Sequential number of SIP requests within a SIP dialog. The number is used to detect out of order requests and retransmissions.
dialog
Dialog is a relationship between two or more SIP user agents that persist for the duration of a call (or session). Dialog is typically created by INVITE request and destroyed when the user agent receives BYE request. Dialogs are identified using the value of Call-ID header field, from tag, and to tag (thus SIP messages having same Call-ID, from tag, and to tag belong to the same dialog).
downstream
The direction of SIP requests (that is from UAC to UAS). See also: UAC, UAS, upstream
forking
A SIP proxy server may send single SIP message to multiple destinations, this process is called "forking". See also: recursive
recursive
When a proxy server receives a negative reply for a request it previously forwarded, it may decide to forward the request again to another destination (such as voicemail server to store a message). This is called recursive (or sequential) forwarding. See also: forking
Request-URI
The URI representing the intended destination of SIP request. Every SIP request contains the Request-URI on the first line of the message header. See also: URI
retransmission
SIP messages are often transferred by means of unreliable transport protocols such as UDP. SIP implementations would send SIP request again if receives no reply within a period of time to compensate for possible packet losses that can occur in the network.
stateful
Proxy or user agent that keeps transaction state in memory while processing SIP messages. Transaction-stateful implementations can associate SIP responses to SIP requests and can absorb retransmissions.
stateless
Very simple user agent or proxy server. Stateless proxies or user agents keep no state in memory while processing SIP messages and thus are not able to correlate SIP messages.
transaction
A collection of SIP messages which includes initial SIP request and all associated SIP replies.
UAC
User Agent Client. The (logical) part of SIP implementation which generates SIP requests and receives and processes SIP responses. See also: branching, downstream, UAS, upstream
UAS
User Agent Server. Logical part of SIP implementation which receives SIP requests and generates SIP responses. See also: downstream, UAC, upstream
upstream
The direction of SIP responses (that is from UAS to UAC). See also: downstream, UAC, UAS
URI
Uniform Resource Identifier. A string representing a resource in the Internet. See also: Request-URI
SMTP
Simple Mail Transport Protocol
TTL
Time To Live, the maximum number of hosts that any given packet or message is allowed to pass before it will be discarded.
VoIP
Voice over IP See also: DTMF
ADPCM
Adaptive Differential Pulse Code Modulation
CDR
Call Detail Record
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