Hi,
We're running a Thirdlane PBX. We have redundant upstream links to a single ISP and SIP trunks through Bandwidth.com.
When we're running on our backup link, then flip back to our primary link, then back to the backup link, our voice traffic acts funny. On inbound calls, the remote caller can hear the called party, but the called party cannot hear the caller. This happens for about 1.50 hrs and then rights itself without our intervention.
Our route announcements on the backup link have (3) ASNs prepended. The remote media gateway is on the Level3 network. We are able to trace to the remote media gateway, and vice versa.
We have verified that inbound packets from the remote media gateway are hitting our router, and our PBX.
But why is the called party unable to hear the caller for 1.50 hrs?
Any ideas welcome.
Thanks,
Adam
you said ASN so I am assuming you're running BGPv4?
have you run traceroutes from both ends to confirm that the path the traffic takes in one direction is the same as the path in the other direction?
is the changes purely IP? Same SIP settings through and through?
is the volume of calls minimal enough to use wireshark and capture udp packets to/from the ip address of your sip peer?
for diagnostic purposes have you tried reducing your peers with bandwidth.com to a single peer and run the same test?
are your outbound calls working with bi-directional audio during this whole event?