<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:st1="urn:schemas-microsoft-com:office:smarttags" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=us-ascii">
<meta name=ProgId content=Word.Document>
<meta name=Generator content="Microsoft Word 11">
<meta name=Originator content="Microsoft Word 11">
<link rel=File-List href="cid:filelist.xml@01C541C0.407BF940">
<link rel=Edit-Time-Data href="cid:editdata.mso">
<!--[if !mso]>
<style>
v\:* {behavior:url(#default#VML);}
o\:* {behavior:url(#default#VML);}
w\:* {behavior:url(#default#VML);}
.shape {behavior:url(#default#VML);}
</style>
<![endif]--><o:SmartTagType
namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="PersonName"/>
<!--[if gte mso 9]><xml>
<o:OfficeDocumentSettings>
<o:DoNotRelyOnCSS/>
</o:OfficeDocumentSettings>
</xml><![endif]--><!--[if gte mso 9]><xml>
<w:WordDocument>
<w:SpellingState>Clean</w:SpellingState>
<w:GrammarState>Clean</w:GrammarState>
<w:DocumentKind>DocumentEmail</w:DocumentKind>
<w:EnvelopeVis/>
<w:ValidateAgainstSchemas/>
<w:SaveIfXMLInvalid>false</w:SaveIfXMLInvalid>
<w:IgnoreMixedContent>false</w:IgnoreMixedContent>
<w:AlwaysShowPlaceholderText>false</w:AlwaysShowPlaceholderText>
<w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel>
</w:WordDocument>
</xml><![endif]--><!--[if gte mso 9]><xml>
<w:LatentStyles DefLockedState="false" LatentStyleCount="156">
</w:LatentStyles>
</xml><![endif]--><!--[if !mso]>
<style>
st1\:*{behavior:url(#default#ieooui) }
</style>
<![endif]-->
<style>
<!--
/* Font Definitions */
@font-face
{font-family:Tahoma;
panose-1:2 11 6 4 3 5 4 4 2 4;
mso-font-charset:0;
mso-generic-font-family:swiss;
mso-font-pitch:variable;
mso-font-signature:1627421319 -2147483648 8 0 66047 0;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{mso-style-parent:"";
margin:0in;
margin-bottom:.0001pt;
mso-pagination:widow-orphan;
font-size:12.0pt;
font-family:"Times New Roman";
mso-fareast-font-family:"Times New Roman";}
a:link, span.MsoHyperlink
{color:blue;
text-decoration:underline;
text-underline:single;}
a:visited, span.MsoHyperlinkFollowed
{color:blue;
text-decoration:underline;
text-underline:single;}
span.EmailStyle17
{mso-style-type:personal-reply;
mso-style-noshow:yes;
mso-ansi-font-size:10.0pt;
mso-bidi-font-size:10.0pt;
font-family:Arial;
mso-ascii-font-family:Arial;
mso-hansi-font-family:Arial;
mso-bidi-font-family:Arial;
color:navy;}
@page Section1
{size:8.5in 11.0in;
margin:1.0in 1.25in 1.0in 1.25in;
mso-header-margin:.5in;
mso-footer-margin:.5in;
mso-paper-source:0;}
div.Section1
{page:Section1;}
-->
</style>
<!--[if gte mso 10]>
<style>
/* Style Definitions */
table.MsoNormalTable
{mso-style-name:"Table Normal";
mso-tstyle-rowband-size:0;
mso-tstyle-colband-size:0;
mso-style-noshow:yes;
mso-style-parent:"";
mso-padding-alt:0in 5.4pt 0in 5.4pt;
mso-para-margin:0in;
mso-para-margin-bottom:.0001pt;
mso-pagination:widow-orphan;
font-size:10.0pt;
font-family:"Times New Roman";
mso-ansi-language:#0400;
mso-fareast-language:#0400;
mso-bidi-language:#0400;}
</style>
<![endif]-->
</head>
<body lang=EN-US link=blue vlink=blue style='tab-interval:.5in'>
<div class=Section1>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Paul,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>It looks like UA ACK 100 Trying. First of
all I don’t believe this is needed. Second of all, it changes CSEQ from
101 INVITE to 100. I think that’s not valid at all. <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>HTH<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Alex<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<div>
<div class=MsoNormal align=center style='text-align:center'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>
<hr size=2 width="100%" align=center tabindex=-1>
</span></font></div>
<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'>
serusers-bounces@iptel.org [mailto:serusers-bounces@lists.iptel.org] <b><span
style='font-weight:bold'>On Behalf Of </span></b><st1:PersonName w:st="on">Java
Rockx</st1:PersonName><br>
<b><span style='font-weight:bold'>Sent:</span></b> Friday, April 15, 2005 10:46
AM<br>
<b><span style='font-weight:bold'>To:</span></b> serusers@lists.iptel.org<br>
<b><span style='font-weight:bold'>Subject:</span></b> [Serusers] Another
Looping Question</span></font><o:p></o:p></p>
</div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal style='margin-bottom:12.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>Hi All.<br>
<br>
Below is a snippet of an INVITE and you can see the usual "trying - your
call is important to us" in the dialog. Anyhow, for some reason SER
occasionally attempts to sent the ACK to itself, which causes a looping
condition. The last ACK shown is the start of the looping condition.<br>
<br>
It only happens on occasion. SER should have consumed the ACK rather than
attempted to forward it.<br>
<br>
Can anyone explain this?<br>
<br>
Regards,<br>
Paul<br>
<br>
IP Legend<br>
-------------------<br>
<a href="http://10.3.0.221">10.3.0.221</a> - SER (behind a Cisco 3600 so ALG
rewrote the IPs)<br>
<a href="http://69.36.46.178">69.36.46.178</a> - NATed SIP UA<br>
<br>
U 2005/04/15 02:19:16.252614 <a href="http://69.35.46.178:5060">69.35.46.178:5060</a>
-> <a href="http://10.3.0.221:5060">10.3.0.221:5060</a><br>
INVITE <a href="mailto:sip:8187768080@sipdev.mycompany.net">sip:8187768080@sipdev.mycompany.net</a>
SIP/2.0.<br>
Via: SIP/2.0/UDP <a href="http://192.168.1.102:5060">192.168.1.102:5060</a>;branch=z9hG4bK3915905414.<br>
From: Test User <<a href="mailto:sip:3215591439@sipdev.mycompany.net">sip:3215591439@sipdev.mycompany.net</a>>;tag=1465261089.<br>
To: <<a href="mailto:sip:8187768080@sipdev.mycompany.net">sip:8187768080@sipdev.mycompany.net</a>>.<br>
Call-ID: <a href="mailto:2671219156@192.168.1.102">2671219156@192.168.1.102</a>.<br>
CSeq: 101 INVITE.<br>
Contact: <sip:3215591439@192.168.1.102:5060>.<br>
Proxy-Authorization: Digest username="3215591439", realm="<a
href="http://sipdev.mycompany.net">sipdev.mycompany.net</a>",
nonce="425f5e0de25efdb3f5a6125dcf2147bf30fe9177", uri="<a
href="mailto:sip:8187768080@sipdev.mycompany.net">sip:8187768080@sipdev.mycompany.net</a>",
response="61996c3bdc10990fec7e245751777516", algorithm=MD5,
cnonce="ae02e47a3355bada49ce344c92f48587", qop=auth, nc=00000002.
max-forwards: 70.<br>
Allow: INVITE, ACK, CANCEL, BYE, REFER, NOTIFY.<br>
Content-Type: application/sdp.<br>
Content-Length: 180.<br>
.<br>
v=0.<br>
o=- 32014 3005 IN IP4 <a href="http://192.168.1.102">192.168.1.102</a>.<br>
s=-.<br>
c=IN IP4 <a href="http://192.168.1.102">192.168.1.102</a>.<br>
t=0 0.<br>
m=audio 13456 RTP/AVP 18 0 8 2 4 101.<br>
a=rtpmap:101 telephone-event/8000.<br>
a=fmtp:101 0-15.<br>
a=ptime:20.<br>
.<br>
<br>
#<br>
U 2005/04/15 02:19:16.276216 <a href="http://10.3.0.221:5060">10.3.0.221:5060</a>
-> <a href="http://69.35.46.178:5060">69.35.46.178:5060</a><br>
SIP/2.0 100 trying -- your call is important to us.<br>
Via: SIP/2.0/UDP <a href="http://192.168.1.102:5060">192.168.1.102:5060</a>;branch=z9hG4bK3915905414;rport=5060;received=<a
href="http://69.35.46.178">69.35.46.178</a>.<br>
From: Test User <<a href="mailto:sip:3215591439@sipdev.mycompany.net">sip:3215591439@sipdev.mycompany.net</a>>;tag=1465261089.<br>
To: <<a href="mailto:sip:8187768080@sipdev.myvox.net">sip:8187768080@sipdev.myvox.net</a>>.<br>
Call-ID: <a href="mailto:2671219156@192.168.1.102">2671219156@192.168.1.102</a>.<br>
CSeq: 101 INVITE.<br>
Content-Length: 0.<br>
.<br>
<br>
#<br>
U 2005/04/15 02:19:16.792795 <a href="http://69.35.46.178:5060">69.35.46.178:5060</a>
-> <a href="http://10.3.0.221:5060">10.3.0.221:5060</a><br>
ACK <a href="mailto:sip:8187768080@sipdev.mycompany.net">sip:8187768080@sipdev.mycompany.net</a>
SIP/2.0.<br>
Via: SIP/2.0/UDP <a href="http://192.168.1.102:5060">192.168.1.102:5060</a>;branch=z9hG4bK3499714875.<br>
From: Test User <<a href="mailto:sip:3215591439@sipdev.mycompany.net">sip:3215591439@sipdev.mycompany.net</a>>;tag=1465261089.<br>
To: <<a href="mailto:sip:8187768080@sipdev.mycompany.net">sip:8187768080@sipdev.mycompany.net</a>>;tag=cdbfe46960d7566fcbe09f199f2b328d.c2bb.<br>
Call-ID: <a href="mailto:2671219156@192.168.1.102">2671219156@192.168.1.102</a>.<br>
CSeq: 100 ACK.<br>
Content-Length: 0.<br>
.<br>
<br>
#<br>
U 2005/04/15 02:19:16.912146 <a href="http://10.3.0.221:5060">10.3.0.221:5060</a>
-> <a href="http://10.3.0.221:5060">10.3.0.221:5060</a><br>
ACK <a href="mailto:sip:8187768080@sipdev.mycompany.net">sip:8187768080@sipdev.mycompany.net</a>
SIP/2.0.<br>
Max-Forwards: 10.<br>
Record-Route: <sip:<a href="http://10.3.0.221">10.3.0.221</a>;ftag=1465261089;lr>.<br>
Via: SIP/2.0/UDP <a href="http://10.3.0.221">10.3.0.221</a>;branch=0.<br>
Via: SIP/2.0/UDP <a href="http://192.168.1.102:5060">192.168.1.102:5060</a>;received=<a
href="http://69.35.46.178">69.35.46.178</a>;branch=z9hG4bK3499714875.<br>
From: Test User <<a href="mailto:sip:3215591439@sipdev.mycompany.net">sip:3215591439@sipdev.mycompany.net</a>>;tag=1465261089.<br>
To: <<a href="mailto:sip:8187768080@sipdev.mycompany.net">sip:8187768080@sipdev.mycompany.net</a>>;tag=cdbfe46960d7566fcbe09f199f2b328d.c2bb.<br>
Call-ID: <a href="mailto:2671219156@192.168.1.102">2671219156@192.168.1.102</a>.<br>
CSeq: 100 ACK.<br>
Content-Length: 0.<br>
P-hint: Local Destination.<o:p></o:p></span></font></p>
</div>
</body>
</html>