We’re experiencing some really odd behavior with qualify enabled in sip.conf on both Asterisk 11.6-cert15 and 13.8-cert3 running on both CentOS 6.7 and Amazon Linux 2016-09 instances in Amazon AWS.
When qualify is enabled (globally, or on an individual peer), we see consistent and reproducible SIP packet retransmissions from the Asterisk instance in our Wireshark traces (see screen shots below where the Asterisk instance is 10.60.254.113 and the other IPs are Brias).
Our problem is that the frequency of the retransmissions, and the call volumes we’re putting on these instances, essentially causes the CPU to spike and call quality to degrade substantially (even with 16x vCPUs) due to the incredible amount of retransmissions on not only the call setup signaling, but on the options messages as well (it looks like a self imposed DoS attack when viewing with ngrep in realtime).
There is nothing in the system logs or asterisk logs (outside of Asterisk noting the retransmissions when qualify is enabled) to indicate a specific issue or misconfiguration. We’ve built several new instances from scratch with very minimal configurations to test the functionality, with the exact same results.
Our team manages several hundred Asterisk instances across the globe, spanning multiple virtualization environments like VMware, Xen, AWS, and GCP - and we’re stumped on this one.
We’ve done the customary googling until our eyes bleed, and come up with nothing . . so before we go and open a bug report, we’re following the bug report check-list.
Any thoughts / ideas would be greatly appreciated.
All the best,