<div dir="ltr">Hi all,<div><br></div><div>I've been assigned a task to investigate why hepic doesn't generate MOS scores ever since we changed the kamailio interface MTU from 9001 -> 1500.</div><div><br></div><div>During my investigation, this is what I have found out so far:</div><div><br></div><div>- Putting MTU back to 9001 removes this condition where no MOS was generated.</div><div>- I did a tcpdump of port 9063 which is the port used to send data to Hepic capture server and saw it reports packets are fragmented:</div><div><br></div><div><span style="color:rgb(209,210,211);font-family:Slack-Lato,appleLogo,sans-serif;font-size:15px;font-variant-ligatures:common-ligatures;background-color:rgb(34,37,41)">3:48:55.895505 IP (tos 0x68, ttl 64, id 38049, offset 0, flags [+], proto UDP (17), length 1500)</span><br style="box-sizing:inherit;color:rgb(209,210,211);font-family:Slack-Lato,appleLogo,sans-serif;font-size:15px;font-variant-ligatures:common-ligatures;background-color:rgb(34,37,41)"><span style="color:rgb(209,210,211);font-family:Slack-Lato,appleLogo,sans-serif;font-size:15px;font-variant-ligatures:common-ligatures;background-color:rgb(34,37,41)">  206.81.181.40.5060 > 10.225.88.239.9063: SIP</span><br style="box-sizing:inherit;color:rgb(209,210,211);font-family:Slack-Lato,appleLogo,sans-serif;font-size:15px;font-variant-ligatures:common-ligatures;background-color:rgb(34,37,41)"><span style="color:rgb(209,210,211);font-family:Slack-Lato,appleLogo,sans-serif;font-size:15px;font-variant-ligatures:common-ligatures;background-color:rgb(34,37,41)">13:48:55.896451 IP (tos 0x68, ttl 64, id 38050, offset 0, flags [+], proto UDP (17), length 1500)</span><br style="box-sizing:inherit;color:rgb(209,210,211);font-family:Slack-Lato,appleLogo,sans-serif;font-size:15px;font-variant-ligatures:common-ligatures;background-color:rgb(34,37,41)"><span style="color:rgb(209,210,211);font-family:Slack-Lato,appleLogo,sans-serif;font-size:15px;font-variant-ligatures:common-ligatures;background-color:rgb(34,37,41)">  206.81.181.40.5060 > 10.225.88.239.9063: SIP</span><br></div><div><br></div><div>- Hepic support also caused by using 1500 MTU on the interface.</div><div>- I tried using the following core parameters to see if they could remedy this issue but didn't seem to work:</div><div><br></div><div>





<p class="gmail-p1" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(86,32,244)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures">## MTU related core settings</span></p>
<p class="gmail-p2" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures">udp4_raw=</span><span class="gmail-s2" style="font-variant-ligatures:no-common-ligatures;color:rgb(202,51,35)">-1</span></p>
<p class="gmail-p2" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures">udp4_raw_mtu=</span><span class="gmail-s2" style="font-variant-ligatures:no-common-ligatures;color:rgb(202,51,35)">1500</span></p><p class="gmail-p2" style="margin:0px;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><br></p></div><div>I can't seem to find any parameters in the siptrace module that controls fragmentation of the packets to Hepic.</div><div><br></div><div>Any suggestions on how else to troubleshoot this?</div><div><br></div><div>Thanks.</div><div><br></div><div>-- <br><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div dir="ltr"><div dir="ltr" style="font-size:12.8px">Andy Chen</div><div dir="ltr" style="font-size:12.8px"><div>Sr. Telephony Lead Engineer</div><div><a href="mailto:achen@thinkingphones.com" target="_blank">achen@</a><a href="http://fuze.com" target="_blank">fuze.com</a></div><div><br></div></div></div></div></div></div></div>

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