Analyzing the log, codecs used, ...

[Edward Velo]

Hi,

I am experiencing a bit with the Fritzbox 7050 log via telnet. In the beginning of each call I always see a list of possible codecs:

Apr 19 16:50:02 voipd[862]: audio: 10 (10 L16/8000)
Apr 19 16:50:02 voipd[862]: audio: 10 (10 L16/8000) => NOT SUPPORTED
Apr 19 16:50:02 voipd[862]: audio: 0 (0 PCMU/8000)
Apr 19 16:50:02 voipd[862]: audio: 0 (0 PCMU/8000) => (0 (0 PCMU/8000))
Apr 19 16:50:02 voipd[862]: audio: 8 (8 PCMA/8000)
Apr 19 16:50:02 voipd[862]: audio: 8 (8 PCMA/8000) => (8 (8 PCMA/8000))
Apr 19 16:50:02 voipd[862]: audio: 3 (3 GSM/8000)
Apr 19 16:50:02 voipd[862]: audio: 3 (3 GSM/8000) => NOT SUPPORTED
Apr 19 16:50:02 voipd[862]: audio: 111 (111 G726-32/8000)
Apr 19 16:50:02 voipd[862]: audio: 111 (111 G726-32/8000) => (111 (111 G726-32/8000))
Apr 19 16:50:02 voipd[862]: audio: 5 (5 DVI4/8000)
Apr 19 16:50:02 voipd[862]: audio: 5 (5 DVI4/8000) => NOT SUPPORTED
Apr 19 16:50:02 voipd[862]: audio: 7 (7 LPC/8000)
Apr 19 16:50:02 voipd[862]: audio: 7 (7 LPC/8000) => NOT SUPPORTED
Apr 19 16:50:02 voipd[862]: audio: 110 (110 speex/8000)
Apr 19 16:50:02 voipd[862]: audio: 110 (110 speex/8000) => NOT SUPPORTED
Apr 19 16:50:02 voipd[862]: audio: 97 (97 iLBC/8000)
Apr 19 16:50:02 voipd[862]: audio: 97 (97 iLBC/8000) => (97 (97 iLBC/8000))
Apr 19 16:50:02 voipd[862]: audio: 18 (18 G729/8000)
Apr 19 16:50:02 voipd[862]: audio: 18 (18 G729/8000) => (18 (18 G729/8000))
Apr 19 16:50:02 voipd[862]: audio: 101 (101 telephone-event/8000)
Apr 19 16:50:02 voipd[862]: audio: 101 (101 telephone-event/8000) => (101 (101 telephone-event/8000))
Apr 19 16:50:02 voipd[862]: xx.xxx.xxx.x 10936 - 7078 audio 0(PCMU)
Apr 19 16:50:02 voipd[862]: Codec PCMU (0) - audio 106000 hold=none (none) (by remote)

What exactly does this mean? Is that the list offered by the VOIP provider, or the list offered by my Fritz!box? Is the first line "audio: 10 (10 L16/8000)" an offer from one device, and the second line "audio: 10 (10 L16/8000) => NOT SUPPORTED" the reply from the other side? Which side?

I always see this list twice before the calls starts... why is that? Is that once from the Fritz!box and once from the voip provider?

What is the number in front of each codec? For instance the "18" in "audio: 18 (18 G729/8000)" ?

Is the "PCMU (0) - audio 106000" codec a good codec? And what is the 106000? The bandwith that will be used in bps? And why is that different from the 8000 that was offered in the beginning "audio: 0 (0 PCMU/8000)" ?

I guess the last line means which codec was used? Does that "by remote" means that the voip provider selected this codec? Does the "hold=none" mean that VAD (voice activation detection) is disabled?

And what does this mean:

Apr 19 16:49:52 voipd[862]: VoIP led value = 18

Also: what does that number 862 means, on each line?

Many questions from me
Thanks for any help in advance!

 

[spongebob]

In order to find out the meaning of the trace lines I would suggest you to investigate the things from another point of view in parallel. Just place a call, record it with the in-built capture functionalties or use my tool at
http://www.ip-phone-forum.de/showthread.php?t=129725 (unfortunately in German only, but you'll catch the point) and compare the FB traces with the real world's scenarios.

I offer my assitance for the latter if the traces of both sides are available.

Regards
Spongebob - finally reaching the next level - 1k postings of nonsens Arrghhh. One DECIMAL k of course...