Which two data frame lengths are supported by iLBC? (Choose two.)

Which two data frame lengths are supported by iLBC? (Choose two.)
A . 10 milliseconds
B . 20 milliseconds
C . 30 milliseconds
D . 40 milliseconds
E . 50 milliseconds
F . 60 milliseconds

Answer: B, C

Explanation:

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.