[asterisk-bugs] [JIRA] (ASTERISK-28342) Ast-to-Ast setup using the same rtcpinterval crashes RTCP and audio stream

[Speed Dial Dave (JIRA)]

    [ https://issues.asterisk.org/jira/browse/ASTERISK-28342?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=246706#comment-246706 ] 

Speed Dial Dave commented on ASTERISK-28342:
--------------------------------------------

I found some time to do more tests, and it indeed seems to be iptables causing the problem. Specifically its connection tracking for UDP traffic appears to be the culprit. Disabling connection tracking for UDP on the relevant ports makes the errors go away:

(this might not be the correct or most suitable way to disable conntrack for this purpose, I don't really know as I avoid iptables as much as I can)

{noformat}
*raw
-A PREROUTING -p udp -m multiport --dports 5060,10000:20000 -j NOTRACK
-A OUTPUT -p udp -m multiport --sports 5060,10000:20000 -j NOTRACK
COMMIT
{noformat}

{noformat}
[root at ast_a blah]# iptables -L -n -t raw
Chain PREROUTING (policy ACCEPT)
target     prot opt source               destination         
CT         udp  --  0.0.0.0/0            0.0.0.0/0            multiport dports 5060,10000:20000 NOTRACK

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination         
CT         udp  --  0.0.0.0/0            0.0.0.0/0            multiport sports 5060,10000:20000 NOTRACK
{noformat}

> Ast-to-Ast setup using the same rtcpinterval crashes RTCP and audio stream
> --------------------------------------------------------------------------
>
>                 Key: ASTERISK-28342
>                 URL: https://issues.asterisk.org/jira/browse/ASTERISK-28342
>             Project: Asterisk
>          Issue Type: Bug
>      Security Level: None
>          Components: Resources/res_rtp_asterisk
>    Affects Versions: 13.21.1, 16.2.1
>         Environment: CentOS 7 (7.6-1810 x86_64)
>            Reporter: Speed Dial Dave
>            Assignee: Speed Dial Dave
>            Severity: Minor
>              Labels: pjsip
>
> When stress-testing PJSIP and Asterisk 16.2.1 by doing direct calls between two identically configured Asterisk setups (over both WAN and LAN) I noticed a specific error message that kept showing up in the logs:
> res_rtp_asterisk.c: RTCP SR transmission error to 1.2.3.4:12345, rtcp halted Operation not permitted
> This started showing up when my tests reached about 200 simultaneously connected calls between the two Asterisk setups. At this level, after a total of 15k calls, the error showed up about 70-80 times on the Asterisk doing the dialing, and about 10-15 times on the one receiving the calls; at ~350 simultaneous calls the number of errors was much higher. When this error popped up the outgoing audio stream ("us") also dropped out from the affected calls, but the channels didn't crash and the calls kept going and finalized normally without any other apparent error.
> As "operation not permitted"/EPERM should be a permission error I first fiddled around with increasing various ulimits as I thought it was some resource starvation, but without luck. After experimenting with various config changes for Asterisk I at one point had different rtcpinterval (rtp.conf) values on the two machines - one was set to 3000 and the other to 6000 - and this completely cleared the problem. Running my test several times more with the two machines having an rtcpinterval difference of only 500 I couldn't get the error to show up again, even when stepping it up to 600 simultaneous calls.



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