Help with network setup - audio breaks up

General Help
1

I have been experiencing some audio breakup on our system. It varies how often it happens or to what degree. Sometimes it happens every couple of minutes and lasts a couple seconds where the caller’s voice sounds choppy. Other times everything sounds choppy all the time and I have to call the person back.

I’m hosting my PBX in my office and the phone I’m using (Sangoma S500) to make the call is on the same network as the PBX (I also have some remote phones). I have a cable internet line with 50mb/s down and 20mb/s up. Here is a voip speed test result of that line.

speed%20test
speed%20test809×523 43.9 KB

I’m using an Asus RT-AC1750 router with these QoS settings

qos1
qos1758×394 66.6 KB

qos2
qos2753×331 66.3 KB

My PBX has an Intel Core i3-7100 CPU @ 3.90GHz CPU, 4GB DDR4 RAM, and an SSD drive.

I do not have the jitter buffer on. I’ve used that in the past and didn’t notice much change. Would turning that on be the first thing to try? Or is there something else I should look at?

2

VoIP needs a stable connection, rather than a fast connection. I’ve seen phones working great with 4-5MB down and 1-2MB up.

What you need to investigate is, where the network interruption is happening. Could be it’s a local issue, could be it’s between you and your provider.

There’s a bunch of tools to capture ping drops, but I’d first try running on my PC two simple constant pings, one that pings the PBX, and one that pings any stable server on the internet, like google.com or 8.8.8.8

Once you confirm that both are stable, AND you had audio issues while ping was fine then you gotta look further.

3

Does this only happen on inbound calls? If you call them back does the problem go away?

4

It happens on inbound and outbound calls.

I’m going to run some ping tests and turn on the jitter buffer to see if I can get some more info or if it fixes it.

5

Ping uses ICMP , the media is using UDP, so ping tests are just not appropriate, the first traffic dropped on a busy network is ICMP . decent QOS (the default) makes the audio a much higher priority, I suggest you enable rtp debugging

RTP set debug on

and watch for any obviously fractured streams.

6

I ran the RTP Debug and got thousands of lines that looked mostly good. But I had this one section with some warnings. This is during a call made by an extension at a remote office. xxx.xxx.xxx.x is the remote office IP. yyy.yyy.yyy.yy is the IP of my trunk provider

[2018-10-19 15:31:05] DEBUG[14859][C-00000056]: res_rtp_asterisk.c:4354 process_dtmf_rfc2833: - RTP 2833 Event: 00000001 (len = 4)
Got  RTP packet from    xxx.xxx.xxx.x:12106 (type 00, seq 033191, ts 1738307872, len 000160)
Sent RTP DTMF packet to yyy.yyy.yyy.yy:11552 (type 101, seq 030740, ts 1738307080, len 000004)
Got  RTP packet from    yyy.yyy.yyy.yy:11552 (type 00, seq 004251, ts 680160, len 000160)
Sent RTP packet to      xxx.xxx.xxx.x:12106 (type 00, seq 021264, ts 679680, len 000160)
Got  RTP packet from    xxx.xxx.xxx.x:12106 (type 101, seq 033192, ts 1738306912, len 000004)
Got  RTP RFC2833 from   xxx.xxx.xxx.x:12106 (type 101, seq 033192, ts 1738306912, len 000004, mark 0, event 00000001, end 1, duration 01040) 
[2018-10-19 15:31:05] DEBUG[14859][C-00000056]: res_rtp_asterisk.c:4354 process_dtmf_rfc2833: - RTP 2833 Event: 00000001 (len = 4)
[2018-10-19 15:31:05] DTMF[14859][C-00000056]: channel.c:4056 __ast_read: DTMF end '1' received on SIP/301-000000d2, duration 130 ms
[2018-10-19 15:31:05] DTMF[14859][C-00000056]: channel.c:4097 __ast_read: DTMF end accepted with begin '1' on SIP/301-000000d2
[2018-10-19 15:31:05] DTMF[14859][C-00000056]: channel.c:4126 __ast_read: DTMF end passthrough '1' on SIP/301-000000d2
Sent RTP DTMF packet to yyy.yyy.yyy.yy:11552 (type 101, seq 030741, ts 1738307080, len 000004)
Sent RTP DTMF packet to yyy.yyy.yyy.yy:11552 (type 101, seq 030742, ts 1738307080, len 000004)
Sent RTP DTMF packet to yyy.yyy.yyy.yy:11552 (type 101, seq 030743, ts 1738307080, len 000004)
Got  RTP packet from    xxx.xxx.xxx.x:12106 (type 101, seq 033192, ts 1738306912, len 000004)
Got  RTP RFC2833 from   xxx.xxx.xxx.x:12106 (type 101, seq 033192, ts 1738306912, len 000004, mark 0, event 00000001, end 1, duration 01040) 
[2018-10-19 15:31:05] DEBUG[14859][C-00000056]: res_rtp_asterisk.c:4354 process_dtmf_rfc2833: - RTP 2833 Event: 00000001 (len = 4)
Got  RTP packet from    xxx.xxx.xxx.x:12106 (type 101, seq 033192, ts 1738306912, len 000004)
Got  RTP RFC2833 from   xxx.xxx.xxx.x:12106 (type 101, seq 033192, ts 1738306912, len 000004, mark 0, event 00000001, end 1, duration 01040) 
[2018-10-19 15:31:05] DEBUG[14859][C-00000056]: res_rtp_asterisk.c:4354 process_dtmf_rfc2833: - RTP 2833 Event: 00000001 (len = 4)
Got  RTP packet from    xxx.xxx.xxx.x:12106 (type 00, seq 033193, ts 1738308032, len 000160)
Sent RTP packet to      yyy.yyy.yyy.yy:11552 (type 00, seq 030744, ts 1738307552, len 000160)
Got  RTP packet from    yyy.yyy.yyy.yy:11552 (type 00, seq 004252, ts 680320, len 000160)
Sent RTP packet to      xxx.xxx.xxx.x:12106 (type 00, seq 021265, ts 679840, len 000160)
Got  RTP packet from    xxx.xxx.xxx.x:12106 (type 00, seq 033194, ts 1738308192, len 000160)
Sent RTP packet to      yyy.yyy.yyy.yy:11552 (type 00, seq 030745, ts 1738307712, len 000160)
Got  RTP packet from    yyy.yyy.yyy.yy:11552 (type 00, seq 004253, ts 680480, len 000160)
Sent RTP packet to      xxx.xxx.xxx.x:12106 (type 00, seq 021266, ts 680000, len 000160)
Got  RTP packet from    xxx.xxx.xxx.x:12106 (type 00, seq 033195, ts 1738308352, len 000160)

Antother warning

Sent RTP packet to      yyy.yyy.yyy.yy:11552 (type 00, seq 026554, ts 1737638992, len 000160)
Sent RTP packet to      yyy.yyy.yyy.yy:13008 (type 00, seq 027993, ts 1737643552, len 000160)
Got  RTP packet from    yyy.yyy.yyy.yy:13008 (type 00, seq 018963, ts 64660329, len 000160)
Sent RTP packet to      xxx.xxx.xxx.x:12114 (type 00, seq 005091, ts 64659848, len 000160)
Got  RTP packet from    xxx.xxx.xxx.x:12106 (type 00, seq 028989, ts 1737639072, len 000160)
[2018-10-19 15:29:42] WARNING[14859][C-00000056]: chan_iax2.c:1240 jb_warning_output: Resyncing the jb. last_delay 0, this delay -217204814, threshold 1000, new offset 217204814
Got  RTP packet from    yyy.yyy.yyy.yy:11552 (type 00, seq 000071, ts 011360, len 000160)
[2018-10-19 15:29:42] WARNING[14918][C-00000056]: chan_iax2.c:1240 jb_warning_output: Resyncing the jb. last_delay 0, this delay -1348, threshold 1000, new offset 1348
Got  RTP packet from    xxx.xxx.xxx.x:12114 (type 00, seq 007059, ts 1737644032, len 000160)
Sent RTP packet to      yyy.yyy.yyy.yy:13008 (type 00, seq 027994, ts 1737643712, len 000160)
Got  RTP packet from    xxx.xxx.xxx.x:12106 (type 00, seq 028990, ts 1737639232, len 000160)
Got  RTP packet from    yyy.yyy.yyy.yy:13008 (type 00, seq 018964, ts 64660489, len 000160)

Another odd spot

Sent RTP packet to      xxx.xxx.xxx.x:12112 (type 00, seq 022774, ts 325280, len 000160)
Got  RTP packet from    yyy.yyy.yyy.yy:17224 (type 00, seq 002037, ts 325920, len 000160)
Sent RTP packet to      xxx.xxx.xxx.x:12112 (type 00, seq 022775, ts 325440, len 000160)
[2018-10-19 15:28:09] ERROR[13806][C-00000055]: pbx_functions.c:701 ast_func_write: Function AUDIOHOOK_INHERIT not registered
Got  RTP packet from    yyy.yyy.yyy.yy:13008 (type 00, seq 018288, ts 64013128, len 000160)
Got  RTP packet from    yyy.yyy.yyy.yy:13008 (type 00, seq 018289, ts 64013288, len 000160)
Got  RTP packet from    yyy.yyy.yyy.yy:13008 (type 00, seq 018290, ts 64013448, len 000160)
Got  RTP packet from    yyy.yyy.yyy.yy:13008 (type 00, seq 018291, ts 64013608, len 000160)
Got  RTP packet from    yyy.yyy.yyy.yy:13008 (type 00, seq 018292, ts 64013768, len 000160)
Got  RTP packet from    yyy.yyy.yyy.yy:13008 (type 00, seq 018293, ts 64013928, len 000160)
Got  RTP packet from    yyy.yyy.yyy.yy:13008 (type 00, seq 018294, ts 64014088, len 000160)
Got  RTP packet from    yyy.yyy.yyy.yy:13008 (type 00, seq 018295, ts 64014248, len 000160)
Got  RTP packet from    yyy.yyy.yyy.yy:13008 (type 00, seq 018296, ts 64014408, len 000160)
Got  RTP packet from    yyy.yyy.yyy.yy:13008 (type 00, seq 018297, ts 64014568, len 000160)
Got  RTP packet from    yyy.yyy.yyy.yy:13008 (type 00, seq 018298, ts 64014728, len 000160)
Got  RTP packet from    yyy.yyy.yyy.yy:13008 (type 00, seq 018299, ts 64014888, len 000160)
Got  RTP packet from    yyy.yyy.yyy.yy:13008 (type 00, seq 018300, ts 64015048, len 000160)
Got  RTP packet from    yyy.yyy.yyy.yy:13008 (type 00, seq 018301, ts 64015208, len 000160)
Got  RTP packet from    yyy.yyy.yyy.yy:13008 (type 00, seq 018302, ts 64015368, len 000160)
Got  RTP packet from    yyy.yyy.yyy.yy:13008 (type 00, seq 018303, ts 64015528, len 000160)
Got  RTP packet from    yyy.yyy.yyy.yy:13008 (type 00, seq 018304, ts 64015688, len 000160)
.....goes on for about 300 lines
7

Yep

Got RTP packet from yyy.yyy.yyy.yy:13008 (type 00, seq 018288, ts 64013128, len 000160)
Got RTP packet from yyy.yyy.yyy.yy:13008 (type 00, seq 018289, ts 64013288, len 000160)
Got RTP packet from yyy.yyy.yyy.yy:13008 (type 00, seq 018290, ts 64013448, len 000160)
Got RTP packet from yyy.yyy.yyy.yy:13008 (type 00, seq 018291, ts 64013608, len 000160)
Got RTP packet from yyy.yyy.yyy.yy:13008 (type 00, seq 018292, ts 64013768, len 000160)
Got RTP packet from yyy.yyy.yyy.yy:13008 (type 00, seq 018293, ts 64013928, len 000160)
Got RTP packet from yyy.yyy.yyy.yy:13008 (type 00, seq 018294, ts 64014088, len 000160)
Got RTP packet from yyy.yyy.yyy.yy:13008 (type 00, seq 018295, ts 64014248, len 000160)
Got RTP packet from yyy.yyy.yyy.yy:13008 (type 00, seq 018296, ts 64014408, len 000160)
Got RTP packet from yyy.yyy.yyy.yy:13008 (type 00, seq 018297, ts 64014568, len 000160)
Got RTP packet from yyy.yyy.yyy.yy:13008 (type 00, seq 018298, ts 64014728, len 000160)
Got RTP packet from yyy.yyy.yyy.yy:13008 (type 00, seq 018299, ts 64014888, len 000160)
Got RTP packet from yyy.yyy.yyy.yy:13008 (type 00, seq 018300, ts 64015048, len 000160)
Got RTP packet from yyy.yyy.yyy.yy:13008 (type 00, seq 018301, ts 64015208, len 000160)
Got RTP packet from yyy.yyy.yyy.yy:13008 (type 00, seq 018302, ts 64015368, len 000160)
Got RTP packet from yyy.yyy.yyy.yy:13008 (type 00, seq 018303, ts 64015528, len 000160)
Got RTP packet from yyy.yyy.yyy.yy:13008 (type 00, seq 018304, ts 64015688, len 000160)

is an audio “break-up”, your getting but not sending and unlikely that any form of jitter buffery can fix it coherently, it can reorder a few out of order packets and fill in couple but you need to fix your network , if QOS isn’t working then jb’s likely wont either and the quick diagnosis is it is your LAN causing the bottle neck.

8

Thanks for the feedback! Any idea where to look first? Should I buy some new VoIP friendly routers? I’m using an ASUS RT-N66R at the remote office location and a Asus RT-AC1750_B1 at the main location with the PBX server. QoS is enabled on both. The phones go through a network switch at the remote office but the PBX is plugged directly into the router at the main location.

9

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