SL1100 - SIP Trunk

[Lectrician]

Hi.

After reading through the post here:

http://www.tek-tips.com/viewthread.cfm?qid=1784152,

I was wondering if you could also help me?

I have a single SIP trunk to evaluate, and have tried to set it up using the information from the supplier. I can make outbound calls, but they cut off after 12 seconds. No incoming calls come in - The number is engaged. The provider says my system is not registering with the SIP trunk.

I have followed this setup guide:

https://www.voicehost.co.uk/sites/d..._and_sv8100_sip_trunk_configuration_guide.pdf

This is my first attempt at SIP trunking :-/

Thanks.

EDIT:

I have made a couple changes, ignoring 10-23 completely. Inbound calls now work. Outbound calls still terminate after 12 seconds though?

Ta!!

 

[pete83uk]

For the outbound calls, ensure SIP ALG is disabled on your router. What router are you using?

 

[Lectrician]

Using a Vigor 2860, I did telnet in and disable it. Will double check though, thanks.

 

[pete83uk]

For incoming calls, have you opened the ports on the Draytek and pointed them to the phone system?

 

[Lectrician]

Yes, I have the ports forwarded and blocked on all external IPs other than those of the SIP provider. Incoming calls are now working, I had followed the guide from the provider to the letter, but it was incorrect. Inbound calls work fine, outbound work, but are dropped at exactly 12 seconds....

Cheers.

 

[pete83uk]

In Firewall - General setup enable "Accept large incoming fragmented UDP or ICMP packets

 

[Lectrician]

The write up said to untick that box, which goes against the grain I admit. I tried both ways. Would that not effect both incoming and outgoing calls though? Incoming calls can last indefinitely, it’s just outbound that are dropping at 12 seconds?

 

[pete83uk]

What ports have you opened up on the Draytek?

 

[Lectrician]

Port UDP 5060 to the IPLA address, Ports UDP 10020–10275 to the VoIP Gateway address.

 

[pete83uk]

Have you restricted 10020-10275 to the voicehost IP? If so, remove the block on those ports so it can communicate to all IP's. Keep 5060 restricted though.

 

[Lectrician]

Just 5060 restricted to voicehosts IPs. Will have another play later today.

 

[Lectrician]

Hi.

Looking deeper into this, it looks like the SL1100 is sending the BYE command and hanging up as it is not receiving an ACK from the receiving party. If I dial from the SL1100 to a SIP phone I have which is independent, that phone shows a 701 error when the call is terminated, which shows the SL1100 is sending the BYE message. I'm assuming there must be something configured incorrectly, or the router is not behaving well. (Apparently the Drayteks are not too good with SIP). I have double checked the SIP_ALG is off in the router. As far as I understand, once the call is setup, the receiving party phone sends an ACK message back to the SL1100, if it doesn't, the system has to clear down. This ACK must be being blocked somewhere.

 

[Lectrician]

Any ideas where to go next with this? I'm struggling now :-(

 

[belevedere]

Bring in an NEC certified tech, or try calling NEC support directly.

 

[pete83uk]

Have you got it sorted?

 

[Lectrician]

No. Checking trunk compatibility. Have you used Voicehost successfully before?

Cheers.