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<DIV><FONT face=Arial size=2>Hello, </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>i am using rtpproxy with openser to act as a RTP
bridge to IP-SS7 gateway. IP-SS7 GW should not be exposed to external
clients directly. </FONT></DIV>
<DIV><FONT face=Arial size=2>Architecture diagram is like this:</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face="Courier New" size=2>|UA1|--SIP/RTP---|</FONT></DIV>
<DIV><FONT face="Courier New" size=2>
|------------------| </FONT><FONT
face="Courier New" size=2>
|-----------| </FONT></DIV>
<DIV><FONT face="Courier New" size=2>
| OpenSer+RTPProxy | --SIP/RTP-- | IP-SS7-GW | </FONT></DIV>
<DIV><FONT face="Courier New"
size=2> |------------------| |-----------|</FONT></DIV>
<DIV><FONT face="Courier New" size=2>|UA2|--SIP/RTP---|</FONT></DIV>
<DIV><FONT face="Courier New" size=2></FONT> </DIV>
<DIV><FONT face="Courier New" size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Problem is when i try to send fax RTP packets
destined for UA2 from IP-SS7 GW are sent directly. </FONT></DIV>
<DIV><FONT face=Arial size=2>They should go through RTPProxy, otherwise media
ports does not match.</FONT></DIV>
<DIV><FONT face=Arial size=2>onreply route looks like:</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>onreply_route[1] {<BR> if
(isflagset(6) && status =~ "(183)|2[0-9][0-9]")
{<BR>
fix_nated_contact();<BR> }</FONT></DIV>
<DIV><FONT face=Arial size=2>
force_rtp_proxy();<BR>}<BR></FONT></DIV>
<DIV><FONT face=Arial size=2>each request is record_route()'ed before it is sent
to be routed back through proxy.</FONT></DIV>
<DIV><FONT face=Arial size=2>I noticed that OpenSer removes top most via header
in 200 OK messages:</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>200 OK message for re-Invite received by
OpenSer:</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2> SIP/2.0 200
OK\r\n<BR> From:
<sip:870000049@sp2.ntt.lt>;tag=4fbb0552\r\n<BR> To:
<sip:70000050@sp2.ntt.lt>;tag=0-13c4-444c9fc6-f4eac-fdd\r\n<BR>
Call-ID: </FONT><A
href="mailto:cc36b0-0-13c4-444c9fc6-f4eac-2c87@sp2.ntt.lt\r\n"><FONT face=Arial
size=2>cc36b0-0-13c4-444c9fc6-f4eac-2c87@sp2.ntt.lt\r\n</FONT></A><BR><FONT
face=Arial size=2> CSeq: 666497904
INVITE\r\n<BR> Via: SIP/2.0/UDP
84.32.0.18;branch=z9hG4bKf67f.2aeace41.0\r\n<BR> Via:
SIP/2.0/UDP
84.32.0.7:5060;branch=z9hG4bK444cbbfca6214604dc9\r\n<BR>
Supported: 100rel\r\n<BR> User-Agent:
SIP-RG\r\n<BR> Contact:
<sip:70000050@84.32.134.143>\r\n<BR> Content-Type:
application/sdp\r\n<BR> Content-Length:
317\r\n<BR> \r\n<BR>
v=0\r\n<BR> o=SIP-N-TA 0 0 IN IP4
84.32.134.143\r\n<BR> s=5420868F 0000 5420868F 0000 01
0\r\n<BR> c=IN IP4 84.32.134.143\r\n<BR> t=0
0\r\n<BR> m=image 4008 udptl t38\r\n<BR>
c=IN IP4 84.32.134.143\r\n<BR>
a=T38FaxVersion:0\r\n<BR>
a=T38MaxBitRate:14400\r\n<BR>
a=T38FaxFillBitRemoval:0\r\n<BR>
a=T38FaxTranscodingMMR:0\r\n<BR>
a=T38FaxTranscodingJBIG:0\r\n<BR>
a=T38FaxRateManagement:transferredTCF\r\n</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>200 OK message sent to IP-SS7 GW by
OpenSer:</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>SIP/2.0 200 OK</FONT></DIV>
<DIV><FONT face=Arial size=2>From:
<sip:870000049@sp2.ntt.lt>;tag=4fbb0552</FONT></DIV>
<DIV><FONT face=Arial size=2>To:
<sip:70000050@sp2.ntt.lt>;tag=0-13c4-444c9fc6-f4eac-fdd</FONT></DIV>
<DIV><FONT face=Arial size=2>Call-ID: </FONT><A
href="mailto:cc36b0-0-13c4-444c9fc6-f4eac-2c87@sp2.ntt.lt"><FONT face=Arial
size=2>cc36b0-0-13c4-444c9fc6-f4eac-2c87@sp2.ntt.lt</FONT></A></DIV>
<DIV><FONT face=Arial size=2>CSeq: 666497904 INVITE</FONT></DIV>
<DIV><FONT face=Arial size=2>Via: SIP/2.0/UDP
84.32.0.7:5060;branch=z9hG4bK444cbbfca6214604dc9</FONT></DIV>
<DIV><FONT face=Arial size=2>Supported: 100rel</FONT></DIV>
<DIV><FONT face=Arial size=2>User-Agent: SIP-RG</FONT></DIV>
<DIV><FONT face=Arial size=2>Contact:
<sip:70000050@84.32.134.143></FONT></DIV>
<DIV><FONT face=Arial size=2>Content-Type: application/sdp</FONT></DIV>
<DIV><FONT face=Arial size=2>Content-Length: 333</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>v=0</FONT></DIV>
<DIV><FONT face=Arial size=2>o=SIP-N-TA 0 0 IN IP4 84.32.134.143</FONT></DIV>
<DIV><FONT face=Arial size=2>s=5420868F 0000 5420868F 0000 01 0</FONT></DIV>
<DIV><FONT face=Arial size=2>c=IN IP4 84.32.134.143</FONT></DIV>
<DIV><FONT face=Arial size=2>t=0 0</FONT></DIV>
<DIV><FONT face=Arial size=2>m=image 39246 udptl t38</FONT></DIV>
<DIV><FONT face=Arial size=2>c=IN IP4 84.32.0.18</FONT></DIV>
<DIV><FONT face=Arial size=2>a=T38FaxVersion:0</FONT></DIV>
<DIV><FONT face=Arial size=2>a=T38MaxBitRate:14400</FONT></DIV>
<DIV><FONT face=Arial size=2>a=T38FaxFillBitRemoval:0</FONT></DIV>
<DIV><FONT face=Arial size=2>a=T38FaxTranscodingMMR:0</FONT></DIV>
<DIV><FONT face=Arial size=2>a=T38FaxTranscodingJBIG:0</FONT></DIV>
<DIV><FONT face=Arial size=2>a=T38FaxRateManagement:transferredTCF</FONT></DIV>
<DIV><FONT face=Arial size=2>a=nortpproxy:yes</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>In this message there is no indication that is came
from SIP proxy (no record-route, no via header), then IP-SS7 GW sends ACK
message directly.</FONT></DIV>
<DIV><FONT face=Arial size=2>This, i suppose, is normal thing, is it? Problem is
that </FONT><FONT face=Arial size=2>IP-SS7 also sends RTP traffic to UA2
directly. This probably happens because of two 'c=' fields in SDP.</FONT></DIV>
<DIV><FONT face=Arial size=2>OpenSer changes only one in media part.
</FONT><FONT face=Arial size=2>Is there a way to change 'c=' field in SDP not
only on media part? </FONT></DIV>
<DIV><FONT face=Arial size=2>Which should take precedence if both can't be
changed?</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>regards, </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Antanas Masevicius</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
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