3 Definitions, symbols and abbreviations

29.3343GPPIMS Application Level Gateway (IMS-ALG) - IMS Access Gateway (IMS-AGW)Iq InterfaceRelease 17Stage 3TS

3.1 Definitions

For the purposes of the present document, the following terms and definitions apply.

Address: term used for "network address" (IP address)

End-to-access edge security: media protection extending between an IMS UE and the first IMS core network node in the media path without being terminated by any intermediary node.

Port: term used for "transport port" (L4 port).

Transcoding: transcoding in general is the translation from one type of encoded media format to another different media format, e.g. G.711 A-law to μ-law or vice versa, G.729 to AMR with 4.75 rate.

NOTE 1: The definition of "transcoding" is according clause 3.10 of ITU-T Recommendation V.152 [23].

NOTE 2: Transcoding belongs to the category of "media aware" IP-to-IP interworking.

Transparent Forwarding: media gateway packet forwarding behaviour with the characteristic of Lx-PDU integrity. This is a unidirectional characteristic of an Lx-PDU flow.

NOTE 3: The definition is according clause 3.2.10 of ITU-T Recommendation H.248.88 [71].

NOTE 4: The semantic covers both traffic directions when applied on H.248 Streams (due to their inherent characteristic of bidirectionality).

Transport Address: term used for the combination of a Network Address and a Transport Port.

For the purposes of the present document, the following terms and definitions as defined in 3GPP TS 23.334 [23] apply:

ICE lite

Full ICE.

3.2 Symbols

For the purposes of the present document, the following symbols apply:

Iq Interface between the IMS Application Level Gateway (ALG) (IMS-ALG) and the IMS Access Gateway (IMS-AGW)

3.3 Abbreviations

For the purposes of the present document, the abbreviations defined in 3GPP TR 21.905 [1] apply, with the following additions. An abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in 3GPP TR 21.905 [1].

ABNF Augmented Backus-Naur Form

ATCF Access Transfer Control Function

ATGW Access Transfer Gateway

B-ALG Bearer Level Application-Level Gateway

BFCP Binary Floor Control Protocol

CCM Codec Control Messages

CVO Coordination of Video Orientation

DBI Delay Budget Information

DSCP Differentiated Service Code Point

e2ae End-to-Access-Edge (security model)

ECN Explicit Congestion Notification

eIMS-AGW IMS Access Gateway enhanced for WebRTC

eP-CSCF P-CSCF enhanced for WebRTC

FECC Far End Camera Control

FIR Full Intra Request

GTT Global Text Telephony

ICE Interactive Connectivity Establishment

IMS-AGW IMS Access Gateway

IMS-ALG IMS Application Level Gateway

IP Internet Protocol

LD Local Descriptor (H.248 protocol element)

MG Media Gateway

MGC Media Gateway Controller

MPS Multimedia Priority Service

MSRP Message Session Relay Protocol

MTSI Multimedia Telephony Service for IMS

NA Not Applicable

NAPT Network Address and Port Translation

NAPT-PT NAPT and Protocol Translation

NAT Network Address Translation

RD Remote Descriptor (H.248 protocol element)

ROI Region of Interest

RTCP RTP Control Protocol

SCTP Stream Control Transport Protocol

SDP Session Description Protocol

SDPCapNeg SDP Capability Negotiation

SRVCC Single Radio Voice Call Continuity

STUN Session Traversal Utilities for NAT

TCP Transmission Control Protocol

TLS Transport Layer Security (protocol)

TMMBN Temporary Maximum Media Stream Bit Rate Notification

TMMBR Temporary Maximum Media Stream Bit Rate Request

ToS Type-of-Service

TISPAN Telecommunications and Internet converged Services and Protocols for Advanced Networking

WebRTC Web Real Time Communication

WIC WebRTC IMS Client

WWSF WebRTC Web Server Function