Jump to content


Photo

>60 TCP handset connections causing Not Reg on handset


  • Please log in to reply
11 replies to this topic

#1 SimonR

SimonR

    Newbie

  • Members
  • Pip
  • 7 posts

Posted 11 September 2015 - 10:40 AM

Hi.

 

We have recently gone from SnomOne 4.5 to version 5 of the Vodia PBX.  The upgrade largely went well, however, when we had more than 60 handsets connect with the TCP protocol, some handsets couldn't register with the PBX anymore.  We have worked around the problem by having handsets 61- 68 running with a UDP protocol connection, but this isn't a solution I want to persist with.

 

We are running Server 2012 Hyper-v VM on a Server 2012 standard (not R2) host. The handsets are Snom 300.

 

Clearly we are hitting a limit either within the PBX or a TCP limit somewhere.  Can someone please advise us on which parameters we should look to change to allow all our handsets to connect with a TCP connection string?  What log files should I be checking to resolve this?

 

Many thanks

Simon



#2 Vodia PBX

Vodia PBX

    Advanced Member

  • Administrators
  • PipPipPip
  • 8,988 posts
  • Gender:Male

Posted 11 September 2015 - 01:24 PM

There is a setting "Maximum number of SIP connections" in admin/SIP/Settings. Make sure that this set to something higher than 60. 



#3 SimonR

SimonR

    Newbie

  • Members
  • Pip
  • 7 posts

Posted 14 September 2015 - 03:27 AM

Thank you for your very quick reply.  The 'Maximum Number of SIP connections' was already set to 500.  I would have thought that, if that was the constraint, we would not be dropping handsets at greater than 60.  Where should we look next ?



#4 Vodia PBX

Vodia PBX

    Advanced Member

  • Administrators
  • PipPipPip
  • 8,988 posts
  • Gender:Male

Posted 14 September 2015 - 06:14 AM

Maybe there is a limitation set by the server. I searched the Internet and found this one, may be good as a quick checklist: https://social.technet.microsoft.com/Forums/windowsserver/en-US/fb7a6ef7-5a70-43a4-b0fe-c0252877467b/concurrent-tcp-connection 



#5 SimonR

SimonR

    Newbie

  • Members
  • Pip
  • 7 posts

Posted 14 September 2015 - 10:40 AM

Hi,

 

We're going to try disabling the TCP Off load this evening, but to be honest, this doesn't feel like a rational change.  It was your technical support team that spotted that we were running out of TCP connections and recommended trying UDP for the extra handsets.  Its important that we understand which configuration parameter is preventing this from working properly.  Is there a log or  a trace file we can setup to see when the TCP connection is being refused or denied, so that we can then dig into the problem with a little more confidence than just Googling a suggestion?

 

I look forward to your response. 

 

Thank you.



#6 Vodia PBX

Vodia PBX

    Advanced Member

  • Administrators
  • PipPipPip
  • 8,988 posts
  • Gender:Male

Posted 14 September 2015 - 11:19 AM

There is no point in trying out unless you know what the problem is. E.g. you can check the registry on the server if there was a limit, and unless you change it, there will be point in restarting the server.

 

Another problem that is causing such problems are usually firewalls. For example if those phones are behind NAT with a router that accepts only 64 connections, it would perfectly explain the problem. In that case, you would have to get a new router or change the setting on that router, if there is one.

 

From the PBX point of view, there are installations with more than 64 connections and usually there is no problem.



#7 SimonR

SimonR

    Newbie

  • Members
  • Pip
  • 7 posts

Posted 14 September 2015 - 12:18 PM

I absolutely agree with what you have said with regards to understanding the problem.  You suggest checking the registry - great suggestion & happy to do that. Which registry setting should I check?

 

With regards to the firewall or NAT, that isn't the problem here.  There is no firewall internally, and their isn't any internal NAT in place.



#8 Vodia PBX

Vodia PBX

    Advanced Member

  • Administrators
  • PipPipPip
  • 8,988 posts
  • Gender:Male

Posted 14 September 2015 - 12:55 PM

As far as I can see from the various forums about Windows Server 2012 unless you changed something with the TCP configuration it should work out of the box. Older Server versions could have license limitations on the number of connections. But if you don't have a license limitation or changed the settings, you should be able from the server side to have millions of TCP connections there. Also if you can still log in to the PBX through HTTP (which is also TCP) it seems unlikely that the PBX process ran out of sockets. So one key question is if the TCP config has been changed on the server.

 

Maybe we are looking into the wrong direction here... Is there anything special about those phones that are now using UDP? Like they are home office phones, going through the public wild Internet. What you could do is to install Wireshark on the server to see what is going on on the cable level, if the TCP connections make it to the server at all. Also in the SIP log, you can see a log message when the PBX has accepted a TCP connection, which means that everything has worked fine into the PBX. 



#9 SimonR

SimonR

    Newbie

  • Members
  • Pip
  • 7 posts

Posted 14 September 2015 - 01:27 PM

Thank you for that last message. The phones are all SNOM300 devices, however, having rebooted all of them only 2 are consistently going to Not Reg. we have swapped those two out for spare phones, and we appear to be ok. We are not intending to make further changes tonight, so we will see whether we achieve stability. The SIP.log is a file we will now watch for any evidence of wierd behaviour. Thanks again. I will update this post later this week.

#10 SimonR

SimonR

    Newbie

  • Members
  • Pip
  • 7 posts

Posted 15 September 2015 - 05:08 AM

Hi,  We still have the same problem.

 

We can get to a stable state with a mix of TCP and UDP connections.  Ideally we want all the phones on the same configuration with the TCP connection string.  When we go over this 'limit' two specific phones go to Not Reg. We have swapped these phones once, to alternative devices to eliminate a device problem. 

 

The SIP log suggests that these phones end up with a timeout at the PBX end of the connection.  I can send the SIP.log fragment on a PM, i'm not keen to post it on the forum.

 

We are currently running PBX version 5.2.3 - is there a later release we should be using?

 

What do you suggest we do?

 

Thank you for your continued help.



#11 Vodia PBX

Vodia PBX

    Advanced Member

  • Administrators
  • PipPipPip
  • 8,988 posts
  • Gender:Male

Posted 15 September 2015 - 08:20 AM

5.2.3 should be fine for this, no need to change the version. I would at this point really install Wireshark and filter for traffic coming from the phone. If you don't want to install software on the PBX server, consider using a port mirror on the Ethernet switch and run Wireshark on another computer (this is less intrusive).



#12 SimonR

SimonR

    Newbie

  • Members
  • Pip
  • 7 posts

Posted 08 October 2015 - 10:38 AM

The issue was resolved by upgrading to PBX version 5.3.0.  The issue was a constraint/limit that had been imposed by a new compiler that was used for version 5.2.3.  This specifically limited the number of SIP connections to 64.

 

We upgraded to version 5.3.0 and we've not had a repeat of this problem.

 

I can also recommend updating the Snom 300 firmware to version 8.7.3.25, as this reinstated the call pickup and the ability for a user to change the ringtone on the handset.






0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users