Hello asterisk-users,

We’re having very odd problems while testing a new server, the configuration is exactly the same as our live cluster, save for a floating address managed by exabgp – the remaining nodes use ucarp. As far as I could tell the versions of asterisk ( 1.8.23.1 ), system packages and even the hardware are the same as on all the others.

The most confusing of all is the output of core show translation recalc:

ast9a*CLI> core show translation recalc 10
Recalculating Codec Translation (number of sample seconds: 10)

Translation times between formats (in microseconds) for one second of data
Source Format (Rows) Destination Format (Columns)

g723 gsm ulaw alaw g726aal2 adpcm slin lpc10 g729 speex ilbc g726 g722 siren7 siren14 slin16 g719 speex16 testlaw
g723 – 2 2 2 2 2 1 2 2 –
2 2 2 – – 3 – – 2
gsm 2 – 2 2 2 2 1 2 2 –
2 2 2 – – 3 – – 2
ulaw 2 2 – 1 2 2 1 2 2 –
2 2 2 – – 3 – – 2
alaw 2 2 1 – 2 2 1 2 2 –
2 2 2 – – 3 – – 2
g726aal2 2 2 2 2 – 2 1 2 2 –
2 2 2 – – 3 – – 2
adpcm 2 2 2 2 2 – 1 2 2 –
2 2 2 – – 3 – – 2
slin 1 1 1 1 1 1 – 1 1 –
1 1 1 – – 2 – – 1
lpc10 2 2 2 2 2 2 1 – 2 –
2 2 2 – – 3 – – 2
g729 2 2 2 2 2 2 1 2 – –
2 2 2 – – 3 – – 2
speex – – – – – – – – – –
– – – – – – – – –
ilbc 2 2 2 2 2 2 1 2 2 –
– 2 2 – – 3 – – 2
g726 2 2 2 2 2 2 1 2 2 –
2 – 2 – – 3 – – 2
g722 2 2 2 2 2 2 1 2 2 –
2 2 – – – 1 – – 2
siren7 – – – – – – – – – –
– – – – – – – – –
siren14 – – – – – – – – – –
– – – – – – – – –
slin16 3 3 3 3 3 3 2 3 3 –
3 3 1 – – – – – 3
g719 – – – – – – – – – –
– – – – – – – – –
speex16 – – – – – – – – – –
– – – – – – – – –
testlaw 2 2 2 2 2 2 1 2 2 –
2 2 2 – – 3 – – –

The above result starts showing up about a minute or two into asterisk’s runtime, and never goes back to normal. We’re not 100% it’s related, but the nodes that are functioning correctly do not exhibit this behaviour. Could this be in-memory caching ? Why on this node and not others ?
On the end user side this seems to be a 5-10 second delay in receiving audio, sometimes no audio is received at all. Nothing unusual in logs. We have also done several packet captures and from the network side it seems like asterisk is just not sending any audio after the call is picked up. We are using UDP for transport. Please let us know if you’ve come across a problem like this before, I’ve had no luck tracking down any similar problems, most people seem to have trouble just with g729, if at all.

Kind regards, Maciej Bonin Systems Administrator Packnet Limited