Calls dropping out on Incredible PBX system - what to blame?

[isaacl]

I set up a phone system using the Incredible PBX system a few weeks ago.
Recently, users have been complaining about calls dropping out, and small drop outs in middle of calls.
I was going to switch the box hosting the phone server, but I checked the resources on the system in the FreePBX Admin panel, and everything is within reason. So it seems like it has something to do with either the network, or the internet.
We have a Comcast connection, and I checked it on speedtest.net - http://www.speedtest.net/result/995853225.png, and pingtest.net - http://www.pingtest.net/result/26329389.png.
The router is running DD-WRT, but I didn't see any way to monitor individual device or port usage.
How would I go about figuring out what the problem might be?
Thanks!

 

[krzykat]

I'd play with wireshark. It even has options for monitoring SIP packets. Quite often, I find that its an internal network issue that is mis-behaving and packets may be going out of order.

RTCP stats can also help.

 

[isaacl]

Pardon the ignorance, but where do I install it - on the phone server, or on a local PC?
And what do I do with it, and what am I looking for?
Thanks a lot!

 

[briankelly63]

You would install it on a different "troubleshooting" PC. The next challenge will be getting the packets to that PC. that can be done by making your network switch send you the same packets as are going to the pbx network interface (see port mirroring on your switch) or by putting two network interfaces on that "troubleshooting" PC or laptop and then bridging them.

There are videos on youtube showing how to use Wireshark...

Router configuration and "canreinvite" settings could be an issue.

Brian

 

[isaacl]

I am using DD-WRT on my router.
Is there anything specific to check, settings-wise?
And my current sipgate trunks look like this:

type=peer
username=username
fromuser=username
secret=password
context=from-trunk
host=sipgate.com
fromdomain=sipgate.com
insecure=very
caninvite=no
canreinvite=no
nat=yes
disallow=all
allow=ulaw&alaw

Is there anything I should be changing?
Thanks!

 

[briankelly63]

Is this on incoming and outgoing? Any pattern at all?

Set up a continuious ping to a reliable destination that you can keep an eye on. Can you also try someone other than Sipgate?

What are the tracert and ping time to the sipgate server?

 

[krzykat]

Here's a nice how-to for setting up port mirroring with DD-WRT and wireshark.

http://www.question-defense.com/201...itate-port-monitoring-on-a-router-switch-port

 

[isaacl]

We're using the Incredible PBX system, using Google Voice, so the Sipgate part needs to stay.
It seems like it's on both incoming and outgoing, though we have incoming through Callcentric, so it doesn't seem to be a provider issue.

I'm assuming it's something with either:
1) Comcast (our internet provider)
2) The network and/or router
3) The phone server

Here's the tracert to sipgate.com from a PC on the same network:

Tracing route to sipgate.com [204.155.28.10]
over a maximum of 30 hops:

  1    <1 ms    <1 ms    <1 ms  DD-WRT [192.168.1.1]
  2    10 ms     9 ms     9 ms  68.80.15.1
  3     9 ms     9 ms     9 ms  te-1-2-ur02.avenel.nj.panjde.comcast.net [68.86.
192.97]
  4     *        9 ms    37 ms  xe-3-0-1-0-ar03.plainfield.nj.panjde.comcast.net
 [68.85.62.9]
  5    11 ms    11 ms    11 ms  te-0-9-0-4-ar01.plainfield.nj.panjde.comcast.net
 [68.85.62.169]
  6    12 ms    11 ms    12 ms  pos-0-6-0-0-cr01.newyork.ny.ibone.comcast.net [6
8.86.90.25]
  7    11 ms    12 ms    11 ms  TenGigabitEthernet4-4.ar4.NYC1.gblx.net [64.215.
24.85]
  8    95 ms    95 ms    96 ms  64.215.30.154
  9    96 ms    95 ms    96 ms  mango.monkeybrains.net [208.90.215.1]
 10     *       95 ms    95 ms  demarc.sipgate.monkeybrains.net [208.90.215.10]

 11    96 ms     *       96 ms  sipgate.com [204.155.28.10]

Trace complete.

I did setup QoS yesterday on my DD-WRT router to see if that would help, but I just set the priority of the phone server's IP address to Exempt (I used 192.168.1.10/32 for the IP address, I hope that's the right way to do it).
I also have port 5060 and port ranges 10000 to 20000 and 5004 to 5082 forwarding to the phone server.

Any ideas?
Thanks a lot!!

 

[isaacl]

I have WireShark set up and running - thanks @krzykat.
I assume I'm supposed to monitor the phone server, so I set it up to monitor that IP.
Can someone help me with what to do now?
Thanks!

 

[isaacl]

I just ran a few internal tests, and all calling within the network is fine.
I then ran the test on http://www.whichvoip.com/voip/speed_test/ppspeed.html.
These were my statistics:


VoIP test statistics
--------------------
Jitter: you --> server: 1.9 ms
Jitter: server --> you: 4.4 ms
Packet loss: you --> server: 0.2 %
Packet loss: server --> you: 1.4 %
Packet discards: 0.0 %
Packets out of order: 0.0 %
Estimated MOS score: 3.7

Speed test statistics
---------------------
Download speed: 472048 bps
Upload speed: 1512480 bps
Download quality of service: 9 %
Upload quality of service: 55 %
Download test type: socket
Upload test type: socket
Maximum TCP delay: 2260 ms
Average download pause: 53 ms
Minimum round trip time to server: 92 ms
Average round trip time to server: 93 ms
Estimated download bandwidth: 17600000bps
Route concurrency: 37.284344
Download TCP forced idle: 68 %
Maximum route speed: 5698688bps


And I was told that my quality of service was measured at 9%, which shows that your connection is unable to produce a constant stream of data.

What do I do now?
Try Comcast?
Thanks!

 

[isaacl]

Just spoke to Comcast, seems like there was something on their end, and they made a few changes.
Gonna try things out and hope they work!!
Thanks all for the help!

 

[oneadvent]

can we get an update?

 

[isaacl]

Spoke to Comcast a few times, still hasn't really been fixed.
The connection seems to be intermittently dropping every few seconds...
And it's not something on my network, after all the testing I've done with internal calls...
Chatting with them again, trying to get to the bottom of the problem.

 

[wardmundy]

Insist on swapping out the cable modem. Works wonders.

 

[isaacl]

Insist on swapping out the cable modem. Works wonders.

Ha
Been insisting on having them ship me the modem, instead of my going to their "local office".
We got it installed not too long ago, and after all, I am paying them a monthly fee to use the modem (Verizon gives it to you for free)
Sounds like they're going to send out a tech...

 

[gregc]

What ever happened?

We had a packet loss issue with Comcast. Took them a week to find the problem a few blocks away. It was affecting the whole neighborhood.

Upside - I now have the local Comcast tech supervisor on speed dial.

 

[lifespeed]

Ha
Been insisting on having them ship me the modem, instead of my going to their "local office".
We got it installed not too long ago, and after all, I am paying them a monthly fee to use the modem (Verizon gives it to you for free)
Sounds like they're going to send out a tech...

Log into the cable modem and check the outgoing signal level. If it is higher than 49 dBmV it indicates the modem is cranking up the power trying to overcome loss. Check your coax wiring. You should have no more than one splitter in the path to the modem, and it should be high quality and work from 10 MHz to 1 GHz.

Lastly, I second the modem recommend. Best one out, IMHO, is Motorola 6120.

 

[kh40s]

Easiest way to check if you have a packet loss problem is to leave a ping running and come back after an hour. Ctrl-c to interrupt and see if there is packet loss.

incidentally, you should avoid using the Exempt class on DD-WRT. Have a read of the post I made regarding QoS on DD-WRT. It's quite long, so I'm not going to repeat anything here...

 

[isaacl]

Sorry for not responding earlier...
We finally got it repaired.
Had a tech come down again. This one was very knowledgeable, unlike the previous ones.
Found that a connection - "barrel" as they call it, on the outside, must have not been working right, and replaced that.
Then came inside, gave us a new Scientific Atlanta 2100 modem.
Also found that a converter to change something with the signal was the wrong thing (they had used 10db instead of 6db), and replaced that.
Have gotten perfect info back on all the tests I try since, so it seems like we're all taken care of.
I also have changed the DD-WRT settings back to Premium, it was on there before...
Thanks everyone for all the help!!

 

[lifespeed]

Like I said, faulty wiring. Glad you got it fixed.