[Asterisk-Users] Interop RTP "Extension headers" for QOS?

[Matt Schulte]

We're setting up a connection with Level3's voip system and when we use
Asterisk or make or recv calls we get an initial pulsing noise. Level3's
Interop team explains that's their RTP extension headers and Asterisk
apparently doesn't know what to do with it. He said we need to either
ignore or of course let the traffic pass. Has anyone heard of this
before? I understand the concept but have no clue where to start
looking. I've been googling all last night about it and have come up
empty.