[asterisk-bugs] [JIRA] (ASTERISK-27421) RTP source learning not working with devices that have some clock issues

[Asterisk Team (JIRA)]

    [ https://issues.asterisk.org/jira/browse/ASTERISK-27421?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=240028#comment-240028 ] 

Asterisk Team commented on ASTERISK-27421:
------------------------------------------

Thanks for creating a report! The issue has entered the triage process. That means the issue will wait in this status until a Bug Marshal has an opportunity to review the issue. Once the issue has been reviewed you will receive comments regarding the next steps towards resolution.

A good first step is for you to review the [Asterisk Issue Guidelines|https://wiki.asterisk.org/wiki/display/AST/Asterisk+Issue+Guidelines] if you haven't already. The guidelines detail what is expected from an Asterisk issue report.

Then, if you are submitting a patch, please review the [Patch Contribution Process|https://wiki.asterisk.org/wiki/display/AST/Patch+Contribution+Process].

> RTP source learning not working with devices that have some clock issues
> ------------------------------------------------------------------------
>
>                 Key: ASTERISK-27421
>                 URL: https://issues.asterisk.org/jira/browse/ASTERISK-27421
>             Project: Asterisk
>          Issue Type: Bug
>      Security Level: None
>          Components: Resources/res_rtp_asterisk
>    Affects Versions: 13.18.2
>            Reporter: nappsoft
>            Severity: Minor
>
> I've observed some Softphones that do not send packets perfectly frequent but for example with 30ms between the first and the second packets and <1 ms between the second and the third. While a jitterbuffer can handle this perfectly, the strict learning algorithm doesn't accept that: it will reset the learning process on every third packet as there are less than 5 ms between these packets.
> I've attached a patch that is changing the implementation in a way that not the time between two packets is taken into account to detect a flood, but the time between the first and the last packet during the learning phase. (A timeout lower than 30ms between 4 packets will not be accepted) what solves the described issue and will still detect flood attacks.



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