<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">The bad udp checksum can happen with cards that offload udp checksumming, which is common. If you are not transcoding, we are not doing any digital modification of the codec payload, and its unlikely that the issue is related to anything freeswitch is doing. You can confirm this by examining the audio stream of the incoming and outgoing rtp stream in wireshark.<div class=""><br class=""><div class=""><br class=""></div><div class="">Mike</div><div class=""><br class=""><div><blockquote type="cite" class=""><div class="">On Oct 17, 2014, at 8:49 AM, Iskren Hadzhinedev <<a href="mailto:iskren.hadzhinedev@ikiji.com" class="">iskren.hadzhinedev@ikiji.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div style="white-space: pre-wrap; font-family: 'Exo 2'; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px;" class="">Hello,</div><div style="white-space: pre-wrap; font-family: 'Exo 2'; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px;" class="">Apologies for the late reply.</div><div style="white-space: pre-wrap; font-family: 'Exo 2'; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px;" class="">I don’t think there’s any transcoding, as the endpoint negotiation is set to “generous” and examining the SDPs shows that both endpoints negotiate on PCMA/PCMU. I got a pcap of the RTP streams with tcpdump and I see that from the 126500 packets, 62964 are marked with “bad udp cksum”. All packets with bad udp checksum are originating from the FreeSWITCH box. Is this information helpful at all and what else can I do to figure out the reason behind these issues? Thank you!</div><p style="white-space: pre-wrap; font-family: 'Exo 2'; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px;" class=""> </p><div style="white-space: pre-wrap; font-family: 'Exo 2'; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px;" class="">Kind regards,</div><div style="white-space: pre-wrap; font-family: 'Exo 2'; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px;" class="">-- </div><div style="white-space: pre-wrap; font-family: 'Exo 2'; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px;" class=""><span style="font-weight: 600;" class="">Iskren Hadzhinedev</span></div><p style="white-space: pre-wrap; font-family: 'Exo 2'; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px;" class=""> </p><div style="white-space: pre-wrap; font-family: 'Exo 2'; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px;" class=""><br class="">On Tuesday 14 October 2014 10:03:32 Michael Jerris wrote:<br class=""></div><p style="white-space: pre-wrap; font-family: 'Exo 2'; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 12px 40px;" class="">is there even any transcoding involved in your scenario? Are the artifacts present in the inbound stream as well. I would get a tcpdump and analyze the inbound and outbound streams to see a bit more detail of what is going on.</p><div style="white-space: pre-wrap; font-family: 'Exo 2'; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px 40px;" class=""><br class=""></div><div style="white-space: pre-wrap; font-family: 'Exo 2'; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px 40px;" class="">Mike</div><div style="white-space: pre-wrap; font-family: 'Exo 2'; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px 40px;" class=""><br class=""></div><div style="white-space: pre-wrap; font-family: 'Exo 2'; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px 40px;" class="">On Oct 14, 2014, at 5:12 AM, Iskren Hadzhinedev <<a href="mailto:iskren.hadzhinedev@ikiji.com" class=""><span style="text-decoration: underline; color: rgb(0, 87, 174);" class="">iskren.hadzhinedev@ikiji.com</span></a>> wrote:</div><div style="white-space: pre-wrap; font-family: 'Exo 2'; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px;" class=""><br class=""></div><p style="white-space: pre-wrap; font-family: 'Exo 2'; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 12px 80px 0px;" class="">Hi everyone,</p><p style="white-space: pre-wrap; font-family: 'Exo 2'; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px 80px;" class=""> </p><div style="white-space: pre-wrap; font-family: 'Exo 2'; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px 80px;" class="">Some of the calls using PCMA/PCMU have artifacts (distorted sound, “robotic” voice, stutter) on what looks like a random basis. The other codecs I have tried don’t have issues (tried GSM, iLBC,G722, G729, SILK). Apart from FreeSWITCH, the only other thing running on the machine is a static webpage served by nginx and the load is almost always at 0. Any help or advise on how to chase down this issue is highly appreciated!</div><p style="white-space: pre-wrap; font-family: 'Exo 2'; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px 80px;" class=""> </p><div style="white-space: pre-wrap; font-family: 'Exo 2'; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px 80px;" class="">System specs:</div><div style="white-space: pre-wrap; font-family: 'Exo 2'; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px 80px;" class="">Machine: Xen VM</div><div style="white-space: pre-wrap; font-family: 'Exo 2'; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px 80px;" class="">RAM: 1GB</div><div style="white-space: pre-wrap; font-family: 'Exo 2'; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px 80px;" class="">CPU: Dualcore 2.4 Ghz 64bit</div><div style="white-space: pre-wrap; font-family: 'Exo 2'; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px 80px;" class="">OS: CentOS 6.5</div><div style="white-space: pre-wrap; font-family: 'Exo 2'; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px 80px;" class="">FreeSWITCH Version: 1.5.13b+git~20140621T003222Z~47891d5caa~64bit</div><p style="white-space: pre-wrap; font-family: 'Exo 2'; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px 80px;" class=""> </p><div style="white-space: pre-wrap; font-family: 'Exo 2'; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px 80px;" class="">Max # simultaneous calls: 12</div><div style="white-space: pre-wrap; font-family: 'Exo 2'; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px 80px;" class="">Calls per second: at most 3</div><p style="white-space: pre-wrap; font-family: 'Exo 2'; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px 80px;" class=""> </p><div style="white-space: pre-wrap; font-family: 'Exo 2'; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px 80px;" class="">Endpoints used for testing:</div><div style="white-space: pre-wrap; font-family: 'Exo 2'; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px 80px;" class="">Hardware phones: Yealink T42G, Yealink T48G, Gigaset DE900, Cisco 7975 (with SIP firmware)</div><div style="white-space: pre-wrap; font-family: 'Exo 2'; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px 80px;" class="">Softphones: CounterPath Bria for Android, CsipSimple (android), Linphone, Jitsi</div><div style="white-space: pre-wrap; font-family: 'Exo 2'; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px 80px;" class="">Mobile provider and a landline via gateway.</div></div></blockquote></div><br class=""></div></div></body></html>