[franzellin]

1) I live in Europe
2) I have 2 SIP Phones with 2 different VoIP accounts with the BETAMAX group and I have 2 IPKALL numbers
3) when I call, for instance, the phone nr1 80% of my attempts are positiv, it means the phone1 rings
4) when I call the phone nr 2, only 10% of my attempts are positiv
5) the problem is independent from which kind of phone i use to call, mobile, classic phone, sip phone
6) sometimes I ear 1 ring and nothing more
7) sometimes I ear nothing
8) when it works the quality is perfect

?1) what could be the reason? I have noticed that the probability that works is higher when in the states is still night...
?2) is there something I should modify in my configurations?

thanks - renato

[franzellin]

problem solved, I reduced the REGISTER time from 3600 to 40 and now everything works normally

[boatman]

It is not desirable to register every 40 seconds. If everyone did that it would place significant additional load on the SIP proxy and could even cause a denial of service situation for the proxy.

Apparently, your SIP device is behind a NAT router? Assuming you are using a Linksys ATA of some sort, try the following.


Set 'NAT Keep Alive Intvl' to: 40
Set 'Register Expires' back to 3600.
Set 'NAT Keep Alive Enable' to: yes
Set 'NAT Keep Alive Msg' blank (yes, make the box empty!)
Set 'NAT Keep Alive Dest' to: $PROXY

[franzellin]

done and works, thanks

[natasha_auh]

Nice answer.Few days back my friend was having the same problem.
This post helped her a lot

[boatman]

In case anyone wants to know how this works, I'll explain.

Leaving 'NAT Keep Alive Msg' blank causes a packet to be sent without any message body. A packet without a body is only 60 to 70 bytes. The router keeps ports open based only on what's in the packet header, so the small packet does the job quite well. The small packet does in fact reach the proxy, but it is ignored because it carries no message body.

A better value for 'NAT Keep Alive Intvl' is 59. This is the number of seconds between sending NAT Keep Alive Packets. Most routers (maybe all routers) remember routes for at least 60 seconds, therefore sending another packet after 59 seconds insures that the SIP port is always open. Many routers remember routes for longer than 60 seconds, often 180 seconds or 300 seconds. In these cases one can set 'NAT Keep Alive Intvl' to 179 or 299 respectively.

[franzellin]

thanks again, that is the right way to explain..