dslreports logo
site
 
    All Forums Hot Topics Gallery
spc

spacer




how-to block ads


Search Topic:
uniqs
1
share rss forum feed

Stewart

join:2005-07-13
kudos:19
reply to pacpac

Re: RTP/NAT router, how to configure PAP2T/FreePBX?

Sorry, I'm still on 1.8 and don't know whether newer versions differ in this regard. You can use SIP debug in Asterisk to see what re-invites, if any, are being sent. Or, use SIP Debug on the device to see where it is sending RTP. Or, run tcpdump on the Asterisk machine -- you don't even have to look at the dump, just stop it after a few seconds and check the packet count.

If you want to be absolutely certain, rig a way to capture the ATA's traffic with Wireshark and see where RTP packets are coming from and where they are going.


pacpac

join:2011-12-18
kudos:1

I can do 'sip set debug on' at CLI and 'tcpdump -i eth0 -n -s0 -v udp port 5074' at root. How do I see a) what re-invites, if any and b) packet count?

When I do 'tcpdump -i eth0 -n -s0 -v udp port 5074' and close with ctr-C, I see this:

67 packets captured
67 packets received by filter
0 packets dropped by kernel


pacpac

join:2011-12-18
kudos:1

I believe I have identified the issue (ref one earlier discussion). When I do 'sip set debug on' and look at the c=IN IP4 ip address, I note the IP of my Asterisk box does not appear in any. I understand that Asterisk is not proxying the media, but saying to send media to the endpoint. Correct?


Stewart

join:2005-07-13
kudos:19

Sorry, I was confused. If you are doing directrtpsetup, then no re-invites are needed, because the initial invites and responses should have the audio go directly between the endpoints.

For detailed debugging, I typically do
tcpdump -s 0 -w foo.cap
then stop it with ctrl-C. I move the foo.cap file to my local PC with sftp and open it in Wireshark to analyze.


pacpac

join:2011-12-18
kudos:1

I have the .cap file on Wireshark. What do I look for in order to confirm Asterisk do not proxy media?


Stewart

join:2005-07-13
kudos:19

said by pacpac:

I have the .cap file on Wireshark. What do I look for in order to confirm Asterisk do not proxy media?

Among other things, if it is proxying media, the vast majority of the packets will be RTP. With directrtpsetup properly working, you won't see any.

However, Wireshark does a great job of interpreting SIP and SDP, so just select one of those packets (if you are using other than port 5060, tell it to decode as SIP). You can then expand SIP, the header and/or body, and see where both endpoints have been told to send RTP.

pacpac

join:2011-12-18
kudos:1

Thanks. No RTP packets and no acitivity on RTP SET DEBUG ON; working as intended.