<div dir="ltr"><div style="font-family:trebuchet ms,sans-serif" class="gmail_default"><span style="color:rgb(0,0,0);font-family:verdana,geneva,helvetica,arial,sans-serif;font-size:13.44px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);display:inline;float:none">Hi all,<span class="gmail-Apple-converted-space"> </span></span><br style="color:rgb(0,0,0);font-family:verdana,geneva,helvetica,arial,sans-serif;font-size:13.44px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255)"><span style="color:rgb(0,0,0);font-family:verdana,geneva,helvetica,arial,sans-serif;font-size:13.44px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);display:inline;float:none">My scenario is as follows:<span class="gmail-Apple-converted-space"> </span></span><br style="color:rgb(0,0,0);font-family:verdana,geneva,helvetica,arial,sans-serif;font-size:13.44px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255)"><span style="color:rgb(0,0,0);font-family:verdana,geneva,helvetica,arial,sans-serif;font-size:13.44px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);display:inline;float:none">I have All the CSCFs on the same IP using different ports.<span class="gmail-Apple-converted-space"> </span></span><br style="color:rgb(0,0,0);font-family:verdana,geneva,helvetica,arial,sans-serif;font-size:13.44px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255)"><span style="color:rgb(0,0,0);font-family:verdana,geneva,helvetica,arial,sans-serif;font-size:13.44px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);display:inline;float:none">P-CSCF advertises a public IP. Rest of the nodes including I-CSCF and S-CSCF listen local only.<span class="gmail-Apple-converted-space"> </span></span><br style="color:rgb(0,0,0);font-family:verdana,geneva,helvetica,arial,sans-serif;font-size:13.44px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255)"><br style="color:rgb(0,0,0);font-family:verdana,geneva,helvetica,arial,sans-serif;font-size:13.44px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255)"><span style="color:rgb(0,0,0);font-family:verdana,geneva,helvetica,arial,sans-serif;font-size:13.44px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);display:inline;float:none">Behavior: When an ACK or PRACK goes from P-CSCF to S-CSCF, the RURI changes such that alias parameter is removed.<span class="gmail-Apple-converted-space"> </span></span><br style="color:rgb(0,0,0);font-family:verdana,geneva,helvetica,arial,sans-serif;font-size:13.44px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255)"><span style="color:rgb(0,0,0);font-family:verdana,geneva,helvetica,arial,sans-serif;font-size:13.44px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);display:inline;float:none">Hence, P-CSCF ends up sending PRACK and ACK on private IP of UE.<span class="gmail-Apple-converted-space"> </span></span><br style="color:rgb(0,0,0);font-family:verdana,geneva,helvetica,arial,sans-serif;font-size:13.44px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255)"><br style="color:rgb(0,0,0);font-family:verdana,geneva,helvetica,arial,sans-serif;font-size:13.44px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255)"><span style="color:rgb(0,0,0);font-family:verdana,geneva,helvetica,arial,sans-serif;font-size:13.44px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);display:inline;float:none">Here's what the config looks like:<span class="gmail-Apple-converted-space"> </span></span><br style="color:rgb(0,0,0);font-family:verdana,geneva,helvetica,arial,sans-serif;font-size:13.44px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255)"><pre style="color:rgb(0,0,0);font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;word-spacing:0px;background-color:rgb(255,255,255)">listen=udp:lo.ca.l.ip:6000 advertise pu.bl.ic.ip:6000
alias=<a href="http://pcscf-ims.domain.net">pcscf-ims.domain.net</a>

#!define WITH_NAT</pre><br style="color:rgb(0,0,0);font-family:verdana,geneva,helvetica,arial,sans-serif;font-size:13.44px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255)"><span style="color:rgb(0,0,0);font-family:verdana,geneva,helvetica,arial,sans-serif;font-size:13.44px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);display:inline;float:none">Any hints?</span></div></div>