SSCA RTP & Media Transport 3

Question 1

At what bitrate does the G.711 codec operate?

Accepted Answer

64 kbps

Answer

G.711 (both μ-law and A-law variants) operates at 64 kbps, providing toll-quality audio without compression.

Question 2

What is the bitrate of the G.729 codec?

Accepted Answer

8 kbps

Answer

G.729 operates at 8 kbps using CS-ACELP compression, making it eight times more bandwidth-efficient than G.711 while maintaining acceptable voice quality.

Question 3

What static RTP payload type number is assigned to G.711 μ-law (PCMU)?

Accepted Answer

0

Answer

Payload type 0 is statically assigned to PCMU (G.711 μ-law), while payload type 8 is assigned to PCMA (G.711 A-law), and payload type 18 to G.729.

Question 4

What security capabilities does SRTP add that standard RTP lacks?

Accepted Answer

Encryption and message authentication of media streams

Answer

SRTP (Secure RTP, RFC 3711) adds AES-based encryption and HMAC-SHA1 authentication to protect the confidentiality and integrity of RTP media streams.

Question 5

What does DTMF stand for?

Accepted Answer

Dual-Tone Multi-Frequency

Answer

DTMF (Dual-Tone Multi-Frequency) is the in-band signaling system used by telephone keypads, where each key press generates two simultaneous audio tones.

(SSCA) Sip School Certified Associate Practice Test

(SSCA) Sip School Certified Associate Practice Test

SSCA RTP & Media Transport 3