Medium data not end end with VoIP to VoIP, why?

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Hello,
I want to provide here only times air for my annoyance and to document a doubtful aspect of the Telefonie over Web.de.

I suffered repeated misfires with pure IP-to-IP Telefonie (both Web.de) during the discussion. Ethereal brought it to the light. The medium data are not negotiated end end.

The RTP data flows over the detour of the dusseligen Asterisk PBXen with Web.de, instead of directly end end to be negotiated. Apparent it comes there also still the-more frequent to “blockages”. No miracle.

In addition the codec from action is so broken-played by the Asterisken that both IP of telephones (BTW, identically, same manufacturer) are constantly forced to G.711, although G.729 is prferiert. I would like to speak however G.729, since I had a volume tariff.

Everything… not inspiring