[asterisk-ss7] chan_ss7 error - Write buffer full on CIC

[Jean Cérien]

Hello all chan_ss7 users

I am facing this issue as well, using chan_ss7 1.4.3 and dahdi complete
2.3.0

There seems to be a consensus to set the jitter buffer max size to 1000ms -
I am concerned as will this induce a 1 sec delay ? Or will the adaptative
mode allow to optimize this ?

Is anyone using this parameters in production ? What feedback can you give ?

I am a bit cautious as this is happening in prod (not test), and dont want
to scr*w things up !

Regards,

J.

On Tue, Jan 26, 2010 at 5:45 PM, marek cervenka <cervajs at fpf.slu.cz> wrote:

> > [Jan 26 19:40:39] NOTICE[9960]: l4isup.c:2434 ss7_write: Write buffer
> full
> > on CIC=122 (wrote only 0 of 160), audio lost (suppress 17).
> > [Jan 26 19:40:50] NOTICE[9960]: l4isup.c:2434 ss7_write: Write buffer
> full
> > on CIC=122 (wrote only 0 of 160), audio lost (suppress 0).
> > [Jan 26 19:41:02] NOTICE[9960]: l4isup.c:2434 ss7_write: Write buffer
> full
> > on CIC=122 (wrote only 0 of 160), audio lost (suppress 5).
> > [Jan 26 19:41:20] NOTICE[9960]: l4isup.c:2434 ss7_write: Write buffer
> full
> > on CIC=122 (wrote only 0 of 160), audio lost (suppress 7).
> > [Jan 26 19:41:38] NOTICE[9960]: l4isup.c:2434 ss7_write: Write buffer
> full
> > on CIC=122 (wrote only 0 of 160), audio lost (suppress 10).
>
> from chan_ss7 faq:
>
> ===text====
> Write buffer full on CIC=4 (wrote only 0 of 160), audio lost.
>
> [Sep 19 18:41:08] NOTICE[10930] l4isup.c: Write buffer full on CIC=4
> (wrote only 0 of 160), audio lost.
> [Sep 19 18:41:08] NOTICE[10930] l4isup.c: Write buffer full on CIC=4
> (wrote only 0 of 160), audio lost.
> [Sep 19 18:41:08] NOTICE[10930] l4isup.c: Write buffer full on CIC=4
> (wrote only 0 of 160), audio lost.
>
> Actually, the "Write buffer" is a kind of jitter-buffer. It is inside the
> zaptel driver and is initialized by chan_ss7 to 4 * 160 bytes (80ms). You
> can increase it to some other multiple of 160, but it requires a
> recompile, and will also increase the audio-delay.
>
> The "write-buffer full" problem often occur because of jitter on the
> IP-net.
>
> In IP-networks, there is allways a time-delay from the time a packet is
> sent to it get received at another host. This delay is unfortunately not
> allways the same. Sometimes, the packets will arrive too slow, and
> sometimes they will arrive too fast. When they arrive too fast, the
> send-buffer is filled, chan_ss7 writes the "Write buffer full" and then
> drop the packets.
>
> This problem does not occur in the conventional circuit-switched telephone
> network, since it is completely synchronous and a dedicated (logical)
> circuit is reserved between the sender and receiver.
>
> To get around this problem, you can setup trafic-shaping on the network,
> insert a bigger buffer in chan_ss7 (which will cause more delay), to
> even-out the difference in time-delay. Maybe it will helpl to configure
> the routers to "chop up" big packets in order to get the small RTP packets
> going smoothly.
>
> ===end text===
>
> you can try:
> - newer version of chan_ss7
> - jitter buffer option in ss7.conf
> [jitter]
> jbenable = yes
> jbmaxsize = 1000
> jbresyncthreshold = 1000
> jbimpl = adaptive
>
>
> ---------------------------------------
> Marek Cervenka
> =======================================
>
>
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