- One party or the other goes "on-hook."
- header and payload
- destination address/es and originator's address
- It does not carry any address information at all.
- error detection
- With DRMF tones or with an IAM in CCITT Signaling System No. 7
- Mouth-to-ear delay, impact of errored frames, lost packets or frames, variation of packet arrival time, prioritizing VoIP traffic over other internet traffic, talker echo, distortion -- voice quality, voice coding algorithm for standardization, sufficient bit rate capacity, optimized standard packet payload size, packet overhead (efficiency), silence suppression)
- Network management, authentication, voice prompts, PSTN interface, QoS records, H.323 functions
- copper pair, ADSL, CATV cable, fiber (SONET/SD), radio, PDH PCM formats
- POTS voice, data octets, DTMF tones
- 80 or 160
- 100 ms
- 400 ms
- Propagation time
- To detect patterns in voice transmission to eventually save on bit rate capacity use
- A buffer may be found in packet routers where at least one frame or packet must be stored. Thus buffer delay would be a function of the number of routers in tandem.
- Speed up the bit rate.
- a) disregard it
b) use a PLC procedure to camouflage the gap
- Carry out a signaling function
- SIP, H.323, MGCP and Megaco H.248
- How to prioritize VoIP packets versus other data packets
- RTP carries out media content function whereas RTCP works with signaling functions of status and control.
- User agents
- Redirect and proxy
- Call agents
- A gateway controller and a gateway
- Terminations and contexts
- By terminationID.
Return to the Quiz: Do you really know VoIP?
This was first published in June 2006