iLBC Data Frame Lengths Supported

BC.

iLBC-Internet Low Bit Rate Codec (iLBC) provides audio quality between that of G.711 and G.729 at bit rates of 15.2 and 13.3 kb/s, while allowing for graceful speech quality degradation in a lossy network due to the speech frames being encoded independently.

By comparison, G.729 does not handle packet loss, delay, and jitter well, due to the dependence between speech frames.

iLBC is supported for SIP, SCCP, H323, and MGCP devices.

iLBC stands for internet Low Bitrate Codec, which is a voice codec used for encoding and decoding audio in Voice over IP (VoIP) communications. It is designed to deliver high-quality audio while using minimal bandwidth. iLBC is an open-source codec, and it is supported on various platforms, including Cisco Unified Communications Manager and other SIP-based VoIP systems.

iLBC supports two data frame lengths, 20 milliseconds, and 30 milliseconds. The data frame length refers to the duration of audio that is encoded or decoded at a time. The longer the data frame length, the better the compression ratio but at the cost of increased latency.

Here are the explanations for each option:

A. 10 milliseconds: This data frame length is not supported by iLBC.

B. 20 milliseconds: This data frame length is supported by iLBC. It is the default frame length, and it provides a good balance between audio quality and bandwidth utilization.

C. 30 milliseconds: This data frame length is supported by iLBC. It provides better audio quality than the 20-millisecond frame length but uses more bandwidth.

D. 40 milliseconds: This data frame length is not supported by iLBC.

E. 50 milliseconds: This data frame length is not supported by iLBC.

F. 60 milliseconds: This data frame length is not supported by iLBC.

In conclusion, the correct answers are B. 20 milliseconds and C. 30 milliseconds.