[asterisk-users] Asterisk and the media path

[Kevin P. Fleming]

On 05/21/2012 07:03 AM, David Wessell wrote:
> I am attempting to get an asterisk server to step out of the media
> path, but am running into a brick wall. Can someone assist? Here's my
> setup..
>
> Ultimate SIP Provider --->  LCR Trunk  (Asterisk 1.6) ---->  PBX (Asterisk 1.8).

In order to be able to know whether any known bugs are interfering with 
what you are trying to do, we need more specific version numbers.

>
> I am attempting to get the trunk to step out of the media stream.
> There is no NAT involved, all machines have a public IP.
>
> In the trunk's sip.conf I have:
>
> directmedia=yes
> directrtpsetup=yes

Please turn off directrtpsetup; it's experimental and doesn't always 
work as you'd expect. In theory it is exactly what you want in this 
scenario, though. If you are using Asterisk 1.6.0.x or 1.6.1.x, 
'directmedia' won't be recognized either.

>
> And on the connection to the pbx I have canreinvite=yes

Why 'directmedia' on one side and 'canreinvite' on the other? They are 
synonyms, you should use the same name on both sides.

>
> On the pbx I have the trunk connection set to canreinvite=yes.

This is unnecessary, unless the devices on the other side of the PBX are 
also on public IPs and you want the PBX to drop out of the media path as 
well.

>
> In the CLI on the LCR trunk I see:
>
>   -- SIP/blahblah-0000000b answered SIP/1722291028-0000000a
>   -- Native bridging SIP/1722291028-0000000a and SIP/siproutes-0000000b
>
> Which would make me think that the lcr trunk is stepping out of the
> media stream. However when I pull up a tcpdump in wireshark I still
> see a RTP connection? Can someone point me in the right direction?

No, native bridging just means that the media stream will be bridged at 
the RTP layer instead of in the Asterisk core. Whether that is done 
using a Packet2Packet bridge in the RTP stack itself, or pushed out to 
the endpoints (directmedia), it's still a native bridge. However, the 
fact that you are seeing this message means you don't have any of the 
large number of reasons that would impede native bridging (transcoding, 
recording, etc.).

It seems like you have the configuration set up (mostly) properly, so in 
order to know what is going on you're going to have to post a more 
complete log snippet, including 'sip debug' output.

-- 
Kevin P. Fleming
Digium, Inc. | Director of Software Technologies
Jabber: kfleming at digium.com | SIP: kpfleming at digium.com | Skype: kpfleming
445 Jan Davis Drive NW - Huntsville, AL 35806 - USA
Check us out at www.digium.com & www.asterisk.org