VoIP glossary

A–F

ACK — SIP request that confirms a final response to an INVITE.

Codec — Software or hardware that encodes and decodes audio or video.

DTMF — Keypad signalling for digits, star, and hash.

E.164 — International telephone-numbering format.

ICE — Method for selecting a working media path through address translation.

G–R

Jitter — Variation in packet arrival time.

MOS — Mean Opinion Score or an estimate of perceived voice quality.

RTP — Protocol that carries real-time audio and video.

RTCP — Companion protocol that reports media statistics.

SRTP — Encrypted and authenticated RTP.

S–Z

SBC — Session border controller; a controlled boundary for SIP and media.

SDP — Session description carried in signalling to negotiate media.

SIP — Signalling protocol used to create, change, and end sessions.

T.38 — Protocol used to relay fax information over packet networks.

VoIP — Voice communication delivered over IP networks.

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