Delay After Answer
I am having an issue with a couple of phones where they ring, but there is a long delay after the phone is picked up before the audio starts.
My setup:
* Server running Asterisk 13.9.1, Dahdi 2.11.1 w/ OSLEC
* Server is CentOS 7
* Quad core CPU with 16GB Ram
* 2 Snom 300 phones.
* NO NAT. Server and phone are on the same subnet with only a gigabit
switch between them.
* Digium TDM400 analog card with 2 incoming analog PSTN lines
When a call comes in, the system answers, IVR plays, caller dials an extension, Snom 300 rings, handset picked up. Caller continues to hear ringing for another 7 to 10 seconds. Answerer hears a click, a quick burst of audio, then silence, then another click and audio is engaged.
I have tried both SIP and RTP debugging and there are absolutely no messages indicating any timeout or retransmit. I am at a total loss.
In the past I’ve always been able to find an answer to issues like this on my own, but this time I just don’t know. I was even beginning to suspect the network switch might be bad, but pinging between the server and the phones shows no packet loss and 0.969ms average response time.
What am I missing*?*
Thanks, Brent Davidson*
*
6 thoughts on - Delay After Answer
I’ve seen this sort of thing where a DNS server is programmed in resolv.conf but is not accessible over the network. Threads get blocked, and you have to wait for the DNS query to timeout.
I’ve faced the same issue. The issue was related to DNS, the reverse lookup query failure caused the delay around(7-9 seconds). The purpose of reverse lookup is to block IP Spoofing attacks.
Regards, Faheem
Well, I thought I had the problem solved. Ported everything over to PJSip and build RDNS records for the phones and the server, but I am still experiencing the problem on incoming calls.
**
Are you sure *nslookup *command is returning as expected?
Also check the output of the below command.
On Tue, Jun 7, 2016 at 11:54 PM, Brent Davidson
Are you using stun? I have seen that when using stun כתב:
בתאריך 8 ביוני 2016 09:54, “Faheem Muhammad”
Another thing i would check is encryption is disabled on the snom כתב:
בתאריך 8 ביוני 2016 10:07, “Israel Gottlieb”