Outgoing and incoming call test with GXP1100 and Netgear N150 WNR1000 router

Created on 2012-02-23 by David Gómez

Switzernet

Outgoing calls

Case 0

Case 1

Case 2

Case 3

Incoming calls

Case 0

Case 1

Case 2

This document describes the test performed with a GXP1100 connected to a Netgear N150 WNR1000 router. This router filters the SIP messages modifying them doing impossible that a call could be established.

Outgoing calls

Case 0

“Case 0” represents a usual call. The call is originated from the phone connected to the problematic router, as the following figure shows:

U 212.147.8.99:64041 -> 91.121.122.64:5060

INVITE sip:0215500331@astrad.switzernet.com SIP/2.0.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK1658359789;rport.

Route: <sip:astrad.switzernet.com:5060;lr>.

From: <sip:41215500335@astrad.switzernet.com>;tag=1665791202.

To: <sip:0215500331@astrad.switzernet.com>.

Call-ID: 1757142519-5060-617@BA.A.A.I.

CSeq: 50 INVITE.

Contact: <sip:41215500335@192.168.1.132:5060>.

Max-Forwards: 70.

User-Agent: Grandstream GXP1100 1.0.1.83.

Privacy: none.

P-Preferred-Identity: <sip:41215500335@astrad.switzernet.com>.

Supported: replaces, path, timer.

Allow: INVITE, ACK, OPTIONS, CANCEL, BYE, SUBSCRIBE, NOTIFY, INFO, REFER, UPDATE, MESSAGE.

Content-Type: application/sdp.

Accept: application/sdp, application/dtmf-relay.

Content-Length:   387.

.

v=0.

o=41215500335 8000 8000 IN IP4 192.168.1.132.

s=SIP Call.

c=IN IP4 192.168.1.132.

t=0 0.

m=audio 5004 RTP/AVP 0 8 18 4 2 97 101.

a=sendrecv.

a=rtpmap:0 PCMU/8000.

a=ptime:20.

a=rtpmap:8 PCMA/8000.

a=rtpmap:18 G729/8000.

a=fmtp:18 annexb=no.

a=rtpmap:4 G723/8000.

a=rtpmap:2 G726-32/8000.

a=rtpmap:97 iLBC/8000.

a=fmtp:97 mode=20.

a=rtpmap:101 telephone-event/8000.

a=fmtp:101 0-15.

U 91.121.122.64:5060 -> 212.147.8.99:64041

SIP/2.0 407 Proxy Authentication Required.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK1658359789;received=212.147.8.99;rport=64041.

From: <sip:41215500335@astrad.switzernet.com>;tag=1665791202.

To: <sip:0215500331@astrad.switzernet.com>;tag=as11aba2cf.

Call-ID: 1757142519-5060-617@BA.A.A.I.

CSeq: 50 INVITE.

User-Agent: Asterisk PBX.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

Proxy-Authenticate: Digest algorithm=MD5, realm="switzernet", nonce="14975ec3".

Content-Length: 0.

U 212.147.8.99:64041 -> 91.121.122.64:5060

ACK sip:0215500331@astrad.switzernet.com SIP/2.0.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK1658359789;rport.

Route: <sip:astrad.switzernet.com:5060;lr>.

From: <sip:41215500335@astrad.switzernet.com>;tag=1665791202.

To: <sip:0215500331@astrad.switzernet.com>;tag=as11aba2cf.

Call-ID: 1757142519-5060-617@BA.A.A.I.

CSeq: 50 ACK.

Content-Length: 0.

U 212.147.8.99:64041 -> 91.121.122.64:5060

INVITE sip:0215500331@astrad.switzernet.com SIP/2.0.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK126966550;rport.

Route: <sip:astrad.switzernet.com:5060;lr>.

From: <sip:41215500335@astrad.switzernet.com>;tag=1665791202.

To: <sip:0215500331@astrad.switzernet.com>.

Call-ID: 1757142519-5060-617@BA.A.A.I.

CSeq: 51 INVITE.

Contact: <sip:41215500335@192.168.1.132:5060>.

Proxy-Authorization: Digest username="41215500335", realm="switzernet", nonce="14975ec3", uri="sip:0215500331@astrad.switzernet.com", response="784a0a54cfc3fdaf0429fe6e8a1cd9d4", algorithm=MD5.

Max-Forwards: 70.

User-Agent: Grandstream GXP1100 1.0.1.83.

Privacy: none.

P-Preferred-Identity: <sip:41215500335@astrad.switzernet.com>.

Supported: replaces, path, timer.

Allow: INVITE, ACK, OPTIONS, CANCEL, BYE, SUBSCRIBE, NOTIFY, INFO, REFER, UPDATE, MESSAGE.

Content-Type: application/sdp.

Accept: application/sdp, application/dtmf-relay.

Content-Length:   387.

.

v=0.

o=41215500335 8000 8000 IN IP4 192.168.1.132.

s=SIP Call.

c=IN IP4 192.168.1.132.

t=0 0.

m=audio 5004 RTP/AVP 0 8 18 4 2 97 101.

a=sendrecv.

a=rtpmap:0 PCMU/8000.

a=ptime:20.

a=rtpmap:8 PCMA/8000.

a=rtpmap:18 G729/8000.

a=fmtp:18 annexb=no.

a=rtpmap:4 G723/8000.

a=rtpmap:2 G726-32/8000.

a=rtpmap:97 iLBC/8000.

a=fmtp:97 mode=20.

a=rtpmap:101 telephone-event/8000.

a=fmtp:101 0-15.

U 91.121.122.64:5060 -> 212.147.8.99:64041

SIP/2.0 100 Trying.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK126966550;received=212.147.8.99;rport=64041.

From: <sip:41215500335@astrad.switzernet.com>;tag=1665791202.

To: <sip:0215500331@astrad.switzernet.com>.

Call-ID: 1757142519-5060-617@BA.A.A.I.

CSeq: 51 INVITE.

User-Agent: Asterisk PBX.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

Contact: <sip:0215500331@91.121.122.64>.

Content-Length: 0.

U 91.121.122.64:5060 -> 178.198.29.66:1028

INVITE sip:41215500331@178.198.29.66:1028 SIP/2.0.

Via: SIP/2.0/UDP 91.121.122.64:5060;branch=z9hG4bK151de984;rport.

From: "41215500335" <sip:41215500335@91.121.122.64>;tag=as5385dad8.

To: <sip:41215500331@178.198.29.66:1028>.

Contact: <sip:41215500335@91.121.122.64>.

Call-ID: 48a74c41336187ec534b55876d01af97@91.121.122.64.

CSeq: 102 INVITE.

User-Agent: Asterisk PBX.

Max-Forwards: 70.

Date: Wed, 15 Feb 2012 13:32:12 GMT.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

h323-conf-id: 1309640735-1712651850-1068828852-1717665581.

Content-Type: application/sdp.

Content-Length: 388.

.

v=0.

o=root 30924 30924 IN IP4 91.121.122.64.

s=session.

c=IN IP4 91.121.122.64.

t=0 0.

m=audio 20458 RTP/AVP 0 8 18 4 111 101.

a=rtpmap:0 PCMU/8000.

a=rtpmap:8 PCMA/8000.

a=rtpmap:18 G729/8000.

a=fmtp:18 annexb=no.

a=rtpmap:4 G723/8000.

a=fmtp:4 annexa=no.

a=rtpmap:111 G726-32/8000.

a=rtpmap:101 telephone-event/8000.

a=fmtp:101 0-16.

a=silenceSupp:off - - - -.

a=ptime:20.

a=sendrecv.

U 178.198.29.66:1028 -> 91.121.122.64:5060

SIP/2.0 100 Trying.

To: <sip:41215500331@178.198.29.66:1028>.

From: "41215500335" <sip:41215500335@91.121.122.64>;tag=as5385dad8.

Call-ID: 48a74c41336187ec534b55876d01af97@91.121.122.64.

CSeq: 102 INVITE.

Via: SIP/2.0/UDP 91.121.122.64:5060;branch=z9hG4bK151de984.

Server: Linksys/SPA921-5.1.8.

Content-Length: 0.

U 178.198.29.66:1028 -> 91.121.122.64:5060

SIP/2.0 180 Ringing.

To: <sip:41215500331@178.198.29.66:1028>;tag=b6d0e7c2e92d51cbi0.

From: "41215500335" <sip:41215500335@91.121.122.64>;tag=as5385dad8.

Call-ID: 48a74c41336187ec534b55876d01af97@91.121.122.64.

CSeq: 102 INVITE.

Via: SIP/2.0/UDP 91.121.122.64:5060;branch=z9hG4bK151de984.

Server: Linksys/SPA921-5.1.8.

Content-Length: 0.

U 91.121.122.64:5060 -> 212.147.8.99:64041

SIP/2.0 180 Ringing.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK126966550;received=212.147.8.99;rport=64041.

From: <sip:41215500335@astrad.switzernet.com>;tag=1665791202.

To: <sip:0215500331@astrad.switzernet.com>;tag=as0b9d9eb7.

Call-ID: 1757142519-5060-617@BA.A.A.I.

CSeq: 51 INVITE.

User-Agent: Asterisk PBX.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

Contact: <sip:0215500331@91.121.122.64>.

Content-Length: 0.

U 178.198.29.66:1028 -> 91.121.122.64:5060

SIP/2.0 200 OK.

To: <sip:41215500331@178.198.29.66:1028>;tag=b6d0e7c2e92d51cbi0.

From: "41215500335" <sip:41215500335@91.121.122.64>;tag=as5385dad8.

Call-ID: 48a74c41336187ec534b55876d01af97@91.121.122.64.

CSeq: 102 INVITE.

Via: SIP/2.0/UDP 91.121.122.64:5060;branch=z9hG4bK151de984.

Contact: "41215500331" <sip:41215500331@192.168.1.40:5060>.

Server: Linksys/SPA921-5.1.8.

Content-Length: 208.

Allow: ACK, BYE, CANCEL, INFO, INVITE, NOTIFY, OPTIONS, REFER.

Supported: replaces.

Content-Type: application/sdp.

.

v=0.

o=- 1225766 1225766 IN IP4 192.168.1.40.

s=-.

c=IN IP4 192.168.1.40.

t=0 0.

m=audio 16410 RTP/AVP 0 101.

a=rtpmap:0 PCMU/8000.

a=rtpmap:101 telephone-event/8000.

a=fmtp:101 0-15.

a=ptime:30.

a=sendrecv.

U 91.121.122.64:5060 -> 178.198.29.66:1028

ACK sip:41215500331@192.168.1.40:5060 SIP/2.0.

Via: SIP/2.0/UDP 91.121.122.64:5060;branch=z9hG4bK1e28c85b;rport.

From: "41215500335" <sip:41215500335@91.121.122.64>;tag=as5385dad8.

To: <sip:41215500331@178.198.29.66:1028>;tag=b6d0e7c2e92d51cbi0.

Contact: <sip:41215500335@91.121.122.64>.

Call-ID: 48a74c41336187ec534b55876d01af97@91.121.122.64.

CSeq: 102 ACK.

User-Agent: Asterisk PBX.

Max-Forwards: 70.

Content-Length: 0.

U 91.121.122.64:5060 -> 212.147.8.99:64041

SIP/2.0 200 OK.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK126966550;received=212.147.8.99;rport=64041.

From: <sip:41215500335@astrad.switzernet.com>;tag=1665791202.

To: <sip:0215500331@astrad.switzernet.com>;tag=as0b9d9eb7.

Call-ID: 1757142519-5060-617@BA.A.A.I.

CSeq: 51 INVITE.

User-Agent: Asterisk PBX.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

Contact: <sip:0215500331@91.121.122.64>.

Content-Type: application/sdp.

Content-Length: 384.

.

v=0.

o=root 30924 30924 IN IP4 91.121.122.64.

s=session.

c=IN IP4 91.121.122.64.

t=0 0.

m=audio 27414 RTP/AVP 0 8 18 4 2 101.

a=rtpmap:0 PCMU/8000.

a=rtpmap:8 PCMA/8000.

a=rtpmap:18 G729/8000.

a=fmtp:18 annexb=no.

a=rtpmap:4 G723/8000.

a=fmtp:4 annexa=no.

a=rtpmap:2 G726-32/8000.

a=rtpmap:101 telephone-event/8000.

a=fmtp:101 0-16.

a=silenceSupp:off - - - -.

a=ptime:20.

a=sendrecv.

U 91.121.122.64:5060 -> 212.147.8.99:64041

SIP/2.0 200 OK.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK126966550;received=212.147.8.99;rport=64041.

From: <sip:41215500335@astrad.switzernet.com>;tag=1665791202.

To: <sip:0215500331@astrad.switzernet.com>;tag=as0b9d9eb7.

Call-ID: 1757142519-5060-617@BA.A.A.I.

CSeq: 51 INVITE.

User-Agent: Asterisk PBX.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

Contact: <sip:0215500331@91.121.122.64>.

Content-Type: application/sdp.

Content-Length: 384.

.

v=0.

o=root 30924 30924 IN IP4 91.121.122.64.

s=session.

c=IN IP4 91.121.122.64.

t=0 0.

m=audio 27414 RTP/AVP 0 8 18 4 2 101.

a=rtpmap:0 PCMU/8000.

a=rtpmap:8 PCMA/8000.

a=rtpmap:18 G729/8000.

a=fmtp:18 annexb=no.

a=rtpmap:4 G723/8000.

a=fmtp:4 annexa=no.

a=rtpmap:2 G726-32/8000.

a=rtpmap:101 telephone-event/8000.

a=fmtp:101 0-16.

a=silenceSupp:off - - - -.

a=ptime:20.

a=sendrecv.

…

…

U 91.121.122.64:5060 -> 178.198.29.66:1028

BYE sip:41215500331@192.168.1.40:5060 SIP/2.0.

Via: SIP/2.0/UDP 91.121.122.64:5060;branch=z9hG4bK3e0ca87d;rport.

From: "41215500335" <sip:41215500335@91.121.122.64>;tag=as5385dad8.

To: <sip:41215500331@178.198.29.66:1028>;tag=b6d0e7c2e92d51cbi0.

Call-ID: 48a74c41336187ec534b55876d01af97@91.121.122.64.

CSeq: 103 BYE.

User-Agent: Asterisk PBX.

Max-Forwards: 70.

Content-Length: 0.

U 178.198.29.66:1028 -> 91.121.122.64:5060

SIP/2.0 200 OK.

To: <sip:41215500331@178.198.29.66:1028>;tag=b6d0e7c2e92d51cbi0.

From: "41215500335" <sip:41215500335@91.121.122.64>;tag=as5385dad8.

Call-ID: 48a74c41336187ec534b55876d01af97@91.121.122.64.

CSeq: 103 BYE.

Via: SIP/2.0/UDP 91.121.122.64:5060;branch=z9hG4bK3e0ca87d.

Server: Linksys/SPA921-5.1.8.

Content-Length: 0.

Wireshark file

As we can see, once the call is established, the OK from the ASTRAD server doesn’t get an ACK response from the caller phone, so after a period of time without ACK answer the ASTRAD guess that the call could not be established and send a BYE message to the destination phone.

This problem is caused because the router, where the caller phone is connected, filters the OK message that the ASTRAD sends doing impossible the answer for the phone.

Case 1

We just have seen that the usual scheme doesn’t work because the router and how it filters the SIP messages. Now, we have included a Perl script and a PROXY-SIP server to the scheme in order to fix this problem.

U 212.147.8.99:64041 -> 91.121.122.64:5060

INVITE sip:0215500331@astrad.switzernet.com SIP/2.0.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK983889695;rport.

Route: <sip:astrad.switzernet.com:5060;lr>.

From: <sip:41215500335@astrad.switzernet.com>;tag=976159729.

To: <sip:0215500331@astrad.switzernet.com>.

Call-ID: 1609358993-5060-618@BA.A.A.I.

CSeq: 60 INVITE.

Contact: <sip:41215500335@192.168.1.132:5060>.

Max-Forwards: 70.

User-Agent: Grandstream GXP1100 1.0.1.83.

Privacy: none.

P-Preferred-Identity: <sip:41215500335@astrad.switzernet.com>.

Supported: replaces, path, timer.

Allow: INVITE, ACK, OPTIONS, CANCEL, BYE, SUBSCRIBE, NOTIFY, INFO, REFER, UPDATE, MESSAGE.

Content-Type: application/sdp.

Accept: application/sdp, application/dtmf-relay.

Content-Length:   387.

.

v=0.

o=41215500335 8000 8000 IN IP4 192.168.1.132.

s=SIP Call.

c=IN IP4 192.168.1.132.

t=0 0.

m=audio 5004 RTP/AVP 0 8 18 4 2 97 101.

a=sendrecv.

a=rtpmap:0 PCMU/8000.

a=ptime:20.

a=rtpmap:8 PCMA/8000.

a=rtpmap:18 G729/8000.

a=fmtp:18 annexb=no.

a=rtpmap:4 G723/8000.

a=rtpmap:2 G726-32/8000.

a=rtpmap:97 iLBC/8000.

a=fmtp:97 mode=20.

a=rtpmap:101 telephone-event/8000.

a=fmtp:101 0-15.

U 91.121.122.64:5060 -> 212.147.8.99:64041

SIP/2.0 407 Proxy Authentication Required.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK983889695;received=212.147.8.99;rport=64041.

From: <sip:41215500335@astrad.switzernet.com>;tag=976159729.

To: <sip:0215500331@astrad.switzernet.com>;tag=as4b49237d.

Call-ID: 1609358993-5060-618@BA.A.A.I.

CSeq: 60 INVITE.

User-Agent: Asterisk PBX.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

Proxy-Authenticate: Digest algorithm=MD5, realm="switzernet", nonce="194c10c1".

Content-Length: 0.

U 212.147.8.99:64041 -> 91.121.122.64:5060

ACK sip:0215500331@astrad.switzernet.com SIP/2.0.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK983889695;rport.

Route: <sip:astrad.switzernet.com:5060;lr>.

From: <sip:41215500335@astrad.switzernet.com>;tag=976159729.

To: <sip:0215500331@astrad.switzernet.com>;tag=as4b49237d.

Call-ID: 1609358993-5060-618@BA.A.A.I.

CSeq: 60 ACK.

Content-Length: 0.

U 212.147.8.99:64041 -> 91.121.122.64:5060

INVITE sip:0215500331@astrad.switzernet.com SIP/2.0.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK840300830;rport.

Route: <sip:astrad.switzernet.com:5060;lr>.

From: <sip:41215500335@astrad.switzernet.com>;tag=976159729.

To: <sip:0215500331@astrad.switzernet.com>.

Call-ID: 1609358993-5060-618@BA.A.A.I.

CSeq: 61 INVITE.

Contact: <sip:41215500335@192.168.1.132:5060>.

Proxy-Authorization: Digest username="41215500335", realm="switzernet", nonce="194c10c1", uri="sip:0215500331@astrad.switzernet.com", response="d1b071b4f7d900766c802b5b95600cb3", algorithm=MD5.

Max-Forwards: 70.

User-Agent: Grandstream GXP1100 1.0.1.83.

Privacy: none.

P-Preferred-Identity: <sip:41215500335@astrad.switzernet.com>.

Supported: replaces, path, timer.

Allow: INVITE, ACK, OPTIONS, CANCEL, BYE, SUBSCRIBE, NOTIFY, INFO, REFER, UPDATE, MESSAGE.

Content-Type: application/sdp.

Accept: application/sdp, application/dtmf-relay.

Content-Length:   387.

.

v=0.

o=41215500335 8000 8000 IN IP4 192.168.1.132.

s=SIP Call.

c=IN IP4 192.168.1.132.

t=0 0.

m=audio 5004 RTP/AVP 0 8 18 4 2 97 101.

a=sendrecv.

a=rtpmap:0 PCMU/8000.

a=ptime:20.

a=rtpmap:8 PCMA/8000.

a=rtpmap:18 G729/8000.

a=fmtp:18 annexb=no.

a=rtpmap:4 G723/8000.

a=rtpmap:2 G726-32/8000.

a=rtpmap:97 iLBC/8000.

a=fmtp:97 mode=20.

a=rtpmap:101 telephone-event/8000.

a=fmtp:101 0-15.

U 91.121.122.64:5060 -> 212.147.8.99:64041

SIP/2.0 100 Trying.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK840300830;received=212.147.8.99;rport=64041.

From: <sip:41215500335@astrad.switzernet.com>;tag=976159729.

To: <sip:0215500331@astrad.switzernet.com>.

Call-ID: 1609358993-5060-618@BA.A.A.I.

CSeq: 61 INVITE.

User-Agent: Asterisk PBX.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

Contact: <sip:0215500331@91.121.122.64>.

Content-Length: 0.

U 91.121.122.64:5060 -> 212.147.8.99:64041

SIP/2.0 302 Moved Temporarily.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK840300830;received=212.147.8.99;rport=64041.

From: <sip:41215500335@astrad.switzernet.com>;tag=976159729.

To: <sip:0215500331@astrad.switzernet.com>;tag=as07b07694.

Call-ID: 1609358993-5060-618@BA.A.A.I.

CSeq: 61 INVITE.

User-Agent: Asterisk PBX.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

Contact: Transfer <sip:0215500331@astproxy.switzernet.com>.

Content-Length: 0.

U 212.147.8.99:64041 -> 91.121.122.64:5060

ACK sip:0215500331@astrad.switzernet.com SIP/2.0.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK840300830;rport.

Route: <sip:astrad.switzernet.com:5060;lr>.

From: <sip:41215500335@astrad.switzernet.com>;tag=976159729.

To: <sip:0215500331@astrad.switzernet.com>;tag=as07b07694.

Call-ID: 1609358993-5060-618@BA.A.A.I.

CSeq: 61 ACK.

Content-Length: 0.

U 212.147.8.99:64041 -> 91.121.122.64:5060

INVITE sip:0215500331@astproxy.switzernet.com SIP/2.0.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK1754228898;rport.

Route: <sip:astrad.switzernet.com:5060;lr>.

From: <sip:41215500335@astrad.switzernet.com>;tag=818397219.

To: <sip:0215500331@astproxy.switzernet.com>.

Call-ID: 701997752-5060-629@BA.A.A.I.

CSeq: 62 INVITE.

Contact: <sip:41215500335@192.168.1.132:5060>.

Proxy-Authorization: Digest username="41215500335", realm="switzernet", nonce="194c10c1", uri="sip:0215500331@astrad.switzernet.com", response="d1b071b4f7d900766c802b5b95600cb3", algorithm=MD5.

Max-Forwards: 70.

User-Agent: Grandstream GXP1100 1.0.1.83.

Privacy: none.

P-Preferred-Identity: <sip:41215500335@astrad.switzernet.com>.

Supported: replaces, path, timer.

Allow: INVITE, ACK, OPTIONS, CANCEL, BYE, SUBSCRIBE, NOTIFY, INFO, REFER, UPDATE, MESSAGE.

Content-Type: application/sdp.

Accept: application/sdp, application/dtmf-relay.

Content-Length:   387.

.

v=0.

o=41215500335 8000 8000 IN IP4 192.168.1.132.

s=SIP Call.

c=IN IP4 192.168.1.132.

t=0 0.

m=audio 5004 RTP/AVP 0 8 18 4 2 97 101.

a=sendrecv.

a=rtpmap:0 PCMU/8000.

a=ptime:20.

a=rtpmap:8 PCMA/8000.

a=rtpmap:18 G729/8000.

a=fmtp:18 annexb=no.

a=rtpmap:4 G723/8000.

a=rtpmap:2 G726-32/8000.

a=rtpmap:97 iLBC/8000.

a=fmtp:97 mode=20.

a=rtpmap:101 telephone-event/8000.

a=fmtp:101 0-15.

U 91.121.122.64:5060 -> 212.147.8.99:64041

SIP/2.0 407 Proxy Authentication Required.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK1754228898;received=212.147.8.99;rport=64041.

From: <sip:41215500335@astrad.switzernet.com>;tag=818397219.

To: <sip:0215500331@astproxy.switzernet.com>;tag=as13a58f3b.

Call-ID: 701997752-5060-629@BA.A.A.I.

CSeq: 62 INVITE.

User-Agent: Asterisk PBX.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

Proxy-Authenticate: Digest algorithm=MD5, realm="switzernet", nonce="03f90c0a".

Content-Length: 0.

U 212.147.8.99:64041 -> 91.121.122.64:5060

ACK sip:0215500331@astproxy.switzernet.com SIP/2.0.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK1754228898;rport.

Route: <sip:astrad.switzernet.com:5060;lr>.

From: <sip:41215500335@astrad.switzernet.com>;tag=818397219.

To: <sip:0215500331@astproxy.switzernet.com>;tag=as13a58f3b.

Call-ID: 701997752-5060-629@BA.A.A.I.

CSeq: 62 ACK.

Content-Length: 0.

U 212.147.8.99:64041 -> 91.121.122.64:5060

INVITE sip:0215500331@astproxy.switzernet.com SIP/2.0.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK105529917;rport.

Route: <sip:astrad.switzernet.com:5060;lr>.

From: <sip:41215500335@astrad.switzernet.com>;tag=818397219.

To: <sip:0215500331@astproxy.switzernet.com>.

Call-ID: 701997752-5060-629@BA.A.A.I.

CSeq: 63 INVITE.

Contact: <sip:41215500335@192.168.1.132:5060>.

Proxy-Authorization: Digest username="41215500335", realm="switzernet", nonce="03f90c0a", uri="sip:0215500331@astproxy.switzernet.com", response="f3a75880693a6e12fd2f90fd5e1a7c22", algorithm=MD5.

Max-Forwards: 70.

User-Agent: Grandstream GXP1100 1.0.1.83.

Privacy: none.

P-Preferred-Identity: <sip:41215500335@astrad.switzernet.com>.

Supported: replaces, path, timer.

Allow: INVITE, ACK, OPTIONS, CANCEL, BYE, SUBSCRIBE, NOTIFY, INFO, REFER, UPDATE, MESSAGE.

Content-Type: application/sdp.

Accept: application/sdp, application/dtmf-relay.

Content-Length:   387.

.

v=0.

o=41215500335 8000 8000 IN IP4 192.168.1.132.

s=SIP Call.

c=IN IP4 192.168.1.132.

t=0 0.

m=audio 5004 RTP/AVP 0 8 18 4 2 97 101.

a=sendrecv.

a=rtpmap:0 PCMU/8000.

a=ptime:20.

a=rtpmap:8 PCMA/8000.

a=rtpmap:18 G729/8000.

a=fmtp:18 annexb=no.

a=rtpmap:4 G723/8000.

a=rtpmap:2 G726-32/8000.

a=rtpmap:97 iLBC/8000.

a=fmtp:97 mode=20.

a=rtpmap:101 telephone-event/8000.

a=fmtp:101 0-15.

U 91.121.122.64:5060 -> 212.147.8.99:64041

SIP/2.0 100 Trying.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK105529917;received=212.147.8.99;rport=64041.

From: <sip:41215500335@astrad.switzernet.com>;tag=818397219.

To: <sip:0215500331@astproxy.switzernet.com>.

Call-ID: 701997752-5060-629@BA.A.A.I.

CSeq: 63 INVITE.

User-Agent: Asterisk PBX.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

Contact: <sip:0215500331@91.121.122.64>.

Content-Length: 0.

U 91.121.122.64:5060 -> 212.147.8.99:64041

SIP/2.0 302 Moved Temporarily.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK105529917;received=212.147.8.99;rport=64041.

From: <sip:41215500335@astrad.switzernet.com>;tag=818397219.

To: <sip:0215500331@astproxy.switzernet.com>;tag=as77c67e0f.

Call-ID: 701997752-5060-629@BA.A.A.I.

CSeq: 63 INVITE.

User-Agent: Asterisk PBX.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

Contact: Transfer <sip:0215500331@astproxy.switzernet.com>.

Content-Length: 0.

U 212.147.8.99:64041 -> 91.121.122.64:5060

ACK sip:0215500331@astproxy.switzernet.com SIP/2.0.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK105529917;rport.

Route: <sip:astrad.switzernet.com:5060;lr>.

From: <sip:41215500335@astrad.switzernet.com>;tag=818397219.

To: <sip:0215500331@astproxy.switzernet.com>;tag=as77c67e0f.

Call-ID: 701997752-5060-629@BA.A.A.I.

CSeq: 63 ACK.

Content-Length: 0.

…

…

Wireshark file

With this scheme, the outgoing calls don’t work. The problem is that the phone doesn’t understand the 302 Moved Temporarily message and always send the messages to the ASTRAD server (Route: <sip:astrad.switzernet.com:5060;lr>), doing a loop.

Case 2

Trying to solve the loop problem that we have with incoming calls in “Case 1”, we use another Perl script configuration.

U 212.147.8.99:64041 -> 91.121.122.64:5060

INVITE sip:0215500331@astrad.switzernet.com SIP/2.0.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK267051270;rport.

Route: <sip:astrad.switzernet.com:5060;lr>.

From: <sip:41215500335@astrad.switzernet.com>;tag=613577038.

To: <sip:0215500331@astrad.switzernet.com>.

Call-ID: 1861442996-5060-2920@BA.A.A.I.

CSeq: 80 INVITE.

Contact: <sip:41215500335@192.168.1.132:5060>.

Max-Forwards: 70.

User-Agent: Grandstream GXP1100 1.0.1.83.

Privacy: none.

P-Preferred-Identity: <sip:41215500335@astrad.switzernet.com>.

Supported: replaces, path, timer.

Allow: INVITE, ACK, OPTIONS, CANCEL, BYE, SUBSCRIBE, NOTIFY, INFO, REFER, UPDATE, MESSAGE.

Content-Type: application/sdp.

Accept: application/sdp, application/dtmf-relay.

Content-Length:   387.

.

v=0.

o=41215500335 8000 8000 IN IP4 192.168.1.132.

s=SIP Call.

c=IN IP4 192.168.1.132.

t=0 0.

m=audio 5004 RTP/AVP 0 8 18 4 2 97 101.

a=sendrecv.

a=rtpmap:0 PCMU/8000.

a=ptime:20.

a=rtpmap:8 PCMA/8000.

a=rtpmap:18 G729/8000.

a=fmtp:18 annexb=no.

a=rtpmap:4 G723/8000.

a=rtpmap:2 G726-32/8000.

a=rtpmap:97 iLBC/8000.

a=fmtp:97 mode=20.

a=rtpmap:101 telephone-event/8000.

a=fmtp:101 0-15.

U 91.121.122.64:5060 -> 212.147.8.99:64041

SIP/2.0 407 Proxy Authentication Required.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK267051270;received=212.147.8.99;rport=64041.

From: <sip:41215500335@astrad.switzernet.com>;tag=613577038.

To: <sip:0215500331@astrad.switzernet.com>;tag=as28ff52c4.

Call-ID: 1861442996-5060-2920@BA.A.A.I.

CSeq: 80 INVITE.

User-Agent: Asterisk PBX.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

Proxy-Authenticate: Digest algorithm=MD5, realm="switzernet", nonce="2d9c8c7e".

Content-Length: 0.

U 212.147.8.99:64041 -> 91.121.122.64:5060

ACK sip:0215500331@astrad.switzernet.com SIP/2.0.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK267051270;rport.

Route: <sip:astrad.switzernet.com:5060;lr>.

From: <sip:41215500335@astrad.switzernet.com>;tag=613577038.

To: <sip:0215500331@astrad.switzernet.com>;tag=as28ff52c4.

Call-ID: 1861442996-5060-2920@BA.A.A.I.

CSeq: 80 ACK.

Content-Length: 0.

U 212.147.8.99:64041 -> 91.121.122.64:5060

INVITE sip:0215500331@astrad.switzernet.com SIP/2.0.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK312846074;rport.

Route: <sip:astrad.switzernet.com:5060;lr>.

From: <sip:41215500335@astrad.switzernet.com>;tag=613577038.

To: <sip:0215500331@astrad.switzernet.com>.

Call-ID: 1861442996-5060-2920@BA.A.A.I.

CSeq: 81 INVITE.

Contact: <sip:41215500335@192.168.1.132:5060>.

Proxy-Authorization: Digest username="41215500335", realm="switzernet", nonce="2d9c8c7e", uri="sip:0215500331@astrad.switzernet.com", response="41e6438551096ef4e8d305fc972fbb8e", algorithm=MD5.

Max-Forwards: 70.

User-Agent: Grandstream GXP1100 1.0.1.83.

Privacy: none.

P-Preferred-Identity: <sip:41215500335@astrad.switzernet.com>.

Supported: replaces, path, timer.

Allow: INVITE, ACK, OPTIONS, CANCEL, BYE, SUBSCRIBE, NOTIFY, INFO, REFER, UPDATE, MESSAGE.

Content-Type: application/sdp.

Accept: application/sdp, application/dtmf-relay.

Content-Length:   387.

.

v=0.

o=41215500335 8000 8000 IN IP4 192.168.1.132.

s=SIP Call.

c=IN IP4 192.168.1.132.

t=0 0.

m=audio 5004 RTP/AVP 0 8 18 4 2 97 101.

a=sendrecv.

a=rtpmap:0 PCMU/8000.

a=ptime:20.

a=rtpmap:8 PCMA/8000.

a=rtpmap:18 G729/8000.

a=fmtp:18 annexb=no.

a=rtpmap:4 G723/8000.

a=rtpmap:2 G726-32/8000.

a=rtpmap:97 iLBC/8000.

a=fmtp:97 mode=20.

a=rtpmap:101 telephone-event/8000.

a=fmtp:101 0-15.

U 91.121.122.64:5060 -> 212.147.8.99:64041

SIP/2.0 100 Trying.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK312846074;received=212.147.8.99;rport=64041.

From: <sip:41215500335@astrad.switzernet.com>;tag=613577038.

To: <sip:0215500331@astrad.switzernet.com>.

Call-ID: 1861442996-5060-2920@BA.A.A.I.

CSeq: 81 INVITE.

User-Agent: Asterisk PBX.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

Contact: <sip:0215500331@91.121.122.64>.

Content-Length: 0.

U 91.121.122.64:5060 -> 212.147.8.99:64041

SIP/2.0 302 Moved Temporarily.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK312846074;received=212.147.8.99;rport=64041.

From: <sip:41215500335@astrad.switzernet.com>;tag=613577038.

To: <sip:0215500331@astrad.switzernet.com>;tag=as489cfae9.

Call-ID: 1861442996-5060-2920@BA.A.A.I.

CSeq: 81 INVITE.

User-Agent: Asterisk PBX.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

Contact: Transfer <sip:0215500331@astproxy.switzernet.com>.

Content-Length: 0.

U 212.147.8.99:64041 -> 91.121.122.64:5060

ACK sip:0215500331@astrad.switzernet.com SIP/2.0.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK312846074;rport.

Route: <sip:astrad.switzernet.com:5060;lr>.

From: <sip:41215500335@astrad.switzernet.com>;tag=613577038.

To: <sip:0215500331@astrad.switzernet.com>;tag=as489cfae9.

Call-ID: 1861442996-5060-2920@BA.A.A.I.

CSeq: 81 ACK.

Content-Length: 0.

U 212.147.8.99:64041 -> 91.121.122.64:5060

INVITE sip:0215500331@astproxy.switzernet.com SIP/2.0.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK1998261075;rport.

Route: <sip:astrad.switzernet.com:5060;lr>.

From: <sip:41215500335@astrad.switzernet.com>;tag=2121474549.

To: <sip:0215500331@astproxy.switzernet.com>.

Call-ID: 543018264-5060-2931@BA.A.A.I.

CSeq: 82 INVITE.

Contact: <sip:41215500335@192.168.1.132:5060>.

Proxy-Authorization: Digest username="41215500335", realm="switzernet", nonce="2d9c8c7e", uri="sip:0215500331@astrad.switzernet.com", response="41e6438551096ef4e8d305fc972fbb8e", algorithm=MD5.

Max-Forwards: 70.

User-Agent: Grandstream GXP1100 1.0.1.83.

Privacy: none.

P-Preferred-Identity: <sip:41215500335@astrad.switzernet.com>.

Supported: replaces, path, timer.

Allow: INVITE, ACK, OPTIONS, CANCEL, BYE, SUBSCRIBE, NOTIFY, INFO, REFER, UPDATE, MESSAGE.

Content-Type: application/sdp.

Accept: application/sdp, application/dtmf-relay.

Content-Length:   387.

.

v=0.

o=41215500335 8000 8000 IN IP4 192.168.1.132.

s=SIP Call.

c=IN IP4 192.168.1.132.

t=0 0.

m=audio 5004 RTP/AVP 0 8 18 4 2 97 101.

a=sendrecv.

a=rtpmap:0 PCMU/8000.

a=ptime:20.

a=rtpmap:8 PCMA/8000.

a=rtpmap:18 G729/8000.

a=fmtp:18 annexb=no.

a=rtpmap:4 G723/8000.

a=rtpmap:2 G726-32/8000.

a=rtpmap:97 iLBC/8000.

a=fmtp:97 mode=20.

a=rtpmap:101 telephone-event/8000.

a=fmtp:101 0-15.

Wireshark file

As happen in “Outgoing calls - Case 1” the caller phone don’t understand the 302 Moved Temporarily message and get into a loop with the ASTRAD server.

Case 3

Trying to solve the loop problem that we have, we use another Perl script configuration.

U 212.147.8.99:64041 -> 91.121.122.64:5060

INVITE sip:0215500331@astrad.switzernet.com SIP/2.0.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK316860591;rport.

Route: <sip:astrad.switzernet.com:5060;lr>.

From: <sip:41215500335@astrad.switzernet.com>;tag=783222727.

To: <sip:0215500331@astrad.switzernet.com>.

Call-ID: 2010967122-5060-4071@BA.A.A.I.

CSeq: 90 INVITE.

Contact: <sip:41215500335@192.168.1.132:5060>.

Max-Forwards: 70.

User-Agent: Grandstream GXP1100 1.0.1.83.

Privacy: none.

P-Preferred-Identity: <sip:41215500335@astrad.switzernet.com>.

Supported: replaces, path, timer.

Allow: INVITE, ACK, OPTIONS, CANCEL, BYE, SUBSCRIBE, NOTIFY, INFO, REFER, UPDATE, MESSAGE.

Content-Type: application/sdp.

Accept: application/sdp, application/dtmf-relay.

Content-Length:   387.

.

v=0.

o=41215500335 8000 8000 IN IP4 192.168.1.132.

s=SIP Call.

c=IN IP4 192.168.1.132.

t=0 0.

m=audio 5004 RTP/AVP 0 8 18 4 2 97 101.

a=sendrecv.

a=rtpmap:0 PCMU/8000.

a=ptime:20.

a=rtpmap:8 PCMA/8000.

a=rtpmap:18 G729/8000.

a=fmtp:18 annexb=no.

a=rtpmap:4 G723/8000.

a=rtpmap:2 G726-32/8000.

a=rtpmap:97 iLBC/8000.

a=fmtp:97 mode=20.

a=rtpmap:101 telephone-event/8000.

a=fmtp:101 0-15.

U 91.121.122.64:5060 -> 212.147.8.99:64041

SIP/2.0 407 Proxy Authentication Required.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK316860591;received=212.147.8.99;rport=64041.

From: <sip:41215500335@astrad.switzernet.com>;tag=783222727.

To: <sip:0215500331@astrad.switzernet.com>;tag=as0de58f01.

Call-ID: 2010967122-5060-4071@BA.A.A.I.

CSeq: 90 INVITE.

User-Agent: Asterisk PBX.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

Proxy-Authenticate: Digest algorithm=MD5, realm="switzernet", nonce="12599bb6".

Content-Length: 0.

U 212.147.8.99:64041 -> 91.121.122.64:5060

ACK sip:0215500331@astrad.switzernet.com SIP/2.0.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK316860591;rport.

Route: <sip:astrad.switzernet.com:5060;lr>.

From: <sip:41215500335@astrad.switzernet.com>;tag=783222727.

To: <sip:0215500331@astrad.switzernet.com>;tag=as0de58f01.

Call-ID: 2010967122-5060-4071@BA.A.A.I.

CSeq: 90 ACK.

Content-Length: 0.

U 212.147.8.99:64041 -> 91.121.122.64:5060

INVITE sip:0215500331@astrad.switzernet.com SIP/2.0.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK799846416;rport.

Route: <sip:astrad.switzernet.com:5060;lr>.

From: <sip:41215500335@astrad.switzernet.com>;tag=783222727.

To: <sip:0215500331@astrad.switzernet.com>.

Call-ID: 2010967122-5060-4071@BA.A.A.I.

CSeq: 91 INVITE.

Contact: <sip:41215500335@192.168.1.132:5060>.

Proxy-Authorization: Digest username="41215500335", realm="switzernet", nonce="12599bb6", uri="sip:0215500331@astrad.switzernet.com", response="b77a412cf17956e9a2ce7cdac0a1304a", algorithm=MD5.

Max-Forwards: 70.

User-Agent: Grandstream GXP1100 1.0.1.83.

Privacy: none.

P-Preferred-Identity: <sip:41215500335@astrad.switzernet.com>.

Supported: replaces, path, timer.

Allow: INVITE, ACK, OPTIONS, CANCEL, BYE, SUBSCRIBE, NOTIFY, INFO, REFER, UPDATE, MESSAGE.

Content-Type: application/sdp.

Accept: application/sdp, application/dtmf-relay.

Content-Length:   387.

.

v=0.

o=41215500335 8000 8000 IN IP4 192.168.1.132.

s=SIP Call.

c=IN IP4 192.168.1.132.

t=0 0.

m=audio 5004 RTP/AVP 0 8 18 4 2 97 101.

a=sendrecv.

a=rtpmap:0 PCMU/8000.

a=ptime:20.

a=rtpmap:8 PCMA/8000.

a=rtpmap:18 G729/8000.

a=fmtp:18 annexb=no.

a=rtpmap:4 G723/8000.

a=rtpmap:2 G726-32/8000.

a=rtpmap:97 iLBC/8000.

a=fmtp:97 mode=20.

a=rtpmap:101 telephone-event/8000.

a=fmtp:101 0-15.

U 91.121.122.64:5060 -> 212.147.8.99:64041

SIP/2.0 100 Trying.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK799846416;received=212.147.8.99;rport=64041.

From: <sip:41215500335@astrad.switzernet.com>;tag=783222727.

To: <sip:0215500331@astrad.switzernet.com>.

Call-ID: 2010967122-5060-4071@BA.A.A.I.

CSeq: 91 INVITE.

User-Agent: Asterisk PBX.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

Contact: <sip:0215500331@91.121.122.64>.

Content-Length: 0.

U 91.121.122.64:5060 -> 212.147.8.99:64041

SIP/2.0 302 Moved Temporarily.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK799846416;received=212.147.8.99;rport=64041.

From: <sip:41215500335@astrad.switzernet.com>;tag=783222727.

To: <sip:0215500331@astrad.switzernet.com>;tag=as3241fb78.

Call-ID: 2010967122-5060-4071@BA.A.A.I.

CSeq: 91 INVITE.

User-Agent: Asterisk PBX.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

Contact: Transfer <sip:0215500331@astproxy.switzernet.com>.

Content-Length: 0.

U 212.147.8.99:64041 -> 91.121.122.64:5060

ACK sip:0215500331@astrad.switzernet.com SIP/2.0.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK799846416;rport.

Route: <sip:astrad.switzernet.com:5060;lr>.

From: <sip:41215500335@astrad.switzernet.com>;tag=783222727.

To: <sip:0215500331@astrad.switzernet.com>;tag=as3241fb78.

Call-ID: 2010967122-5060-4071@BA.A.A.I.

CSeq: 91 ACK.

Content-Length: 0.

U 212.147.8.99:64041 -> 91.121.122.64:5060

INVITE sip:0215500331@astproxy.switzernet.com SIP/2.0.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK1480857286;rport.

Route: <sip:astrad.switzernet.com:5060;lr>.

From: <sip:41215500335@astrad.switzernet.com>;tag=742674718.

To: <sip:0215500331@astproxy.switzernet.com>.

Call-ID: 744212756-5060-4082@BA.A.A.I.

CSeq: 92 INVITE.

Contact: <sip:41215500335@192.168.1.132:5060>.

Proxy-Authorization: Digest username="41215500335", realm="switzernet", nonce="12599bb6", uri="sip:0215500331@astrad.switzernet.com", response="b77a412cf17956e9a2ce7cdac0a1304a", algorithm=MD5.

Max-Forwards: 70.

User-Agent: Grandstream GXP1100 1.0.1.83.

Privacy: none.

P-Preferred-Identity: <sip:41215500335@astrad.switzernet.com>.

Supported: replaces, path, timer.

Allow: INVITE, ACK, OPTIONS, CANCEL, BYE, SUBSCRIBE, NOTIFY, INFO, REFER, UPDATE, MESSAGE.

Content-Type: application/sdp.

Accept: application/sdp, application/dtmf-relay.

Content-Length:   387.

.

v=0.

o=41215500335 8000 8000 IN IP4 192.168.1.132.

s=SIP Call.

c=IN IP4 192.168.1.132.

t=0 0.

m=audio 5004 RTP/AVP 0 8 18 4 2 97 101.

a=sendrecv.

a=rtpmap:0 PCMU/8000.

a=ptime:20.

a=rtpmap:8 PCMA/8000.

a=rtpmap:18 G729/8000.

a=fmtp:18 annexb=no.

a=rtpmap:4 G723/8000.

a=rtpmap:2 G726-32/8000.

a=rtpmap:97 iLBC/8000.

a=fmtp:97 mode=20.

a=rtpmap:101 telephone-event/8000.

a=fmtp:101 0-15.

Wireshark file

As we can see, we still have the problem with the caller phone redirection. We ca conclude that this phone model doesn’t support the 302 Moved Temporarily message.

Also we can conclude that the GXP1100 couldn’t reach a destination if it’s connected to a Netgear N150 WNR1000 router.

Incoming calls

Case 0

This case shows the usual scheme for an incoming call. The call is generated to a telephone connected to the problematic router as you can see in the picture:

U 178.198.29.66:1028 -> 91.121.122.64:5060

INVITE sip:0215500335@astrad.switzernet.com SIP/2.0.

Via: SIP/2.0/UDP 192.168.1.40:5060;branch=z9hG4bK-58c2c600.

From: "41215500331" <sip:41215500331@astrad.switzernet.com>;tag=dc12daa38c55b708o0.

To: <sip:0215500335@astrad.switzernet.com>.

Call-ID: 7573aff-6487725c@192.168.1.40.

CSeq: 101 INVITE.

Max-Forwards: 70.

Contact: "41215500331" <sip:41215500331@192.168.1.40:5060>.

Expires: 240.

User-Agent: Linksys/SPA921-5.1.8.

Content-Length: 397.

Allow: ACK, BYE, CANCEL, INFO, INVITE, NOTIFY, OPTIONS, REFER.

Supported: replaces.

Content-Type: application/sdp.

.

v=0.

o=- 1300176 1300176 IN IP4 192.168.1.40.

s=-.

c=IN IP4 192.168.1.40.

t=0 0.

m=audio 16414 RTP/AVP 0 2 4 8 18 96 97 98 101.

a=rtpmap:0 PCMU/8000.

a=rtpmap:2 G726-32/8000.

a=rtpmap:4 G723/8000.

a=rtpmap:8 PCMA/8000.

a=rtpmap:18 G729a/8000.

a=rtpmap:96 G726-40/8000.

a=rtpmap:97 G726-24/8000.

a=rtpmap:98 G726-16/8000.

a=rtpmap:101 telephone-event/8000.

a=fmtp:101 0-15.

a=ptime:30.

a=sendrecv.

U 91.121.122.64:5060 -> 178.198.29.66:1028

SIP/2.0 407 Proxy Authentication Required.

Via: SIP/2.0/UDP 192.168.1.40:5060;branch=z9hG4bK-58c2c600;received=178.198.29.66.

From: "41215500331" <sip:41215500331@astrad.switzernet.com>;tag=dc12daa38c55b708o0.

To: <sip:0215500335@astrad.switzernet.com>;tag=as7adb518f.

Call-ID: 7573aff-6487725c@192.168.1.40.

CSeq: 101 INVITE.

User-Agent: Asterisk PBX.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

Proxy-Authenticate: Digest algorithm=MD5, realm="switzernet", nonce="23084ccb".

Content-Length: 0.

U 178.198.29.66:1028 -> 91.121.122.64:5060

ACK sip:0215500335@astrad.switzernet.com SIP/2.0.

Via: SIP/2.0/UDP 192.168.1.40:5060;branch=z9hG4bK-58c2c600.

From: "41215500331" <sip:41215500331@astrad.switzernet.com>;tag=dc12daa38c55b708o0.

To: <sip:0215500335@astrad.switzernet.com>;tag=as7adb518f.

Call-ID: 7573aff-6487725c@192.168.1.40.

CSeq: 101 ACK.

Max-Forwards: 70.

Contact: "41215500331" <sip:41215500331@192.168.1.40:5060>.

User-Agent: Linksys/SPA921-5.1.8.

Content-Length: 0.

U 178.198.29.66:1028 -> 91.121.122.64:5060

INVITE sip:0215500335@astrad.switzernet.com SIP/2.0.

Via: SIP/2.0/UDP 192.168.1.40:5060;branch=z9hG4bK-cc1c85e0.

From: "41215500331" <sip:41215500331@astrad.switzernet.com>;tag=dc12daa38c55b708o0.

To: <sip:0215500335@astrad.switzernet.com>.

Call-ID: 7573aff-6487725c@192.168.1.40.

CSeq: 102 INVITE.

Max-Forwards: 70.

Proxy-Authorization: Digest username="41215500331",realm="switzernet",nonce="23084ccb",uri="sip:0215500335@astrad.switzernet.com",algorithm=MD5,response="b6a1f2a16338e0c5be6b313c2cbaf77a".

Contact: "41215500331" <sip:41215500331@192.168.1.40:5060>.

Expires: 240.

User-Agent: Linksys/SPA921-5.1.8.

Content-Length: 397.

Allow: ACK, BYE, CANCEL, INFO, INVITE, NOTIFY, OPTIONS, REFER.

Supported: replaces.

Content-Type: application/sdp.

.

v=0.

o=- 1300176 1300176 IN IP4 192.168.1.40.

s=-.

c=IN IP4 192.168.1.40.

t=0 0.

m=audio 16414 RTP/AVP 0 2 4 8 18 96 97 98 101.

a=rtpmap:0 PCMU/8000.

a=rtpmap:2 G726-32/8000.

a=rtpmap:4 G723/8000.

a=rtpmap:8 PCMA/8000.

a=rtpmap:18 G729a/8000.

a=rtpmap:96 G726-40/8000.

a=rtpmap:97 G726-24/8000.

a=rtpmap:98 G726-16/8000.

a=rtpmap:101 telephone-event/8000.

a=fmtp:101 0-15.

a=ptime:30.

a=sendrecv.

U 91.121.122.64:5060 -> 178.198.29.66:1028

SIP/2.0 100 Trying.

Via: SIP/2.0/UDP 192.168.1.40:5060;branch=z9hG4bK-cc1c85e0;received=178.198.29.66.

From: "41215500331" <sip:41215500331@astrad.switzernet.com>;tag=dc12daa38c55b708o0.

To: <sip:0215500335@astrad.switzernet.com>.

Call-ID: 7573aff-6487725c@192.168.1.40.

CSeq: 102 INVITE.

User-Agent: Asterisk PBX.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

Contact: <sip:0215500335@91.121.122.64>.

Content-Length: 0.

U 91.121.122.64:5060 -> 178.198.29.66:1028

SIP/2.0 183 Session Progress.

Via: SIP/2.0/UDP 192.168.1.40:5060;branch=z9hG4bK-cc1c85e0;received=178.198.29.66.

From: "41215500331" <sip:41215500331@astrad.switzernet.com>;tag=dc12daa38c55b708o0.

To: <sip:0215500335@astrad.switzernet.com>;tag=as193071d7.

Call-ID: 7573aff-6487725c@192.168.1.40.

CSeq: 102 INVITE.

User-Agent: Asterisk PBX.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

Contact: <sip:0215500335@91.121.122.64>.

Content-Type: application/sdp.

Content-Length: 384.

.

v=0.

o=root 30924 30924 IN IP4 91.121.122.64.

s=session.

c=IN IP4 91.121.122.64.

t=0 0.

m=audio 12224 RTP/AVP 0 8 18 4 2 101.

a=rtpmap:0 PCMU/8000.

a=rtpmap:8 PCMA/8000.

a=rtpmap:18 G729/8000.

a=fmtp:18 annexb=no.

a=rtpmap:4 G723/8000.

a=fmtp:4 annexa=no.

a=rtpmap:2 G726-32/8000.

a=rtpmap:101 telephone-event/8000.

a=fmtp:101 0-16.

a=silenceSupp:off - - - -.

a=ptime:20.

a=sendrecv.

U 91.121.122.64:5060 -> 212.147.8.99:64041

INVITE sip:41215500335@212.147.8.99:64041 SIP/2.0.

Via: SIP/2.0/UDP 91.121.122.64:5060;branch=z9hG4bK2423d72c;rport.

From: "41215500331" <sip:41215500331@91.121.122.64>;tag=as004f5b87.

To: <sip:41215500335@212.147.8.99:64041>.

Contact: <sip:41215500331@91.121.122.64>.

Call-ID: 7f5db6275e80cb58445b93c840b5881e@91.121.122.64.

CSeq: 102 INVITE.

User-Agent: Asterisk PBX.

Max-Forwards: 70.

Date: Wed, 15 Feb 2012 13:44:38 GMT.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

h323-conf-id: 684267750-1139933510-1735632590-1371098423.

Content-Type: application/sdp.

Content-Length: 388.

.

v=0.

o=root 30924 30924 IN IP4 91.121.122.64.

s=session.

c=IN IP4 91.121.122.64.

t=0 0.

m=audio 27340 RTP/AVP 0 8 18 4 111 101.

a=rtpmap:0 PCMU/8000.

a=rtpmap:8 PCMA/8000.

a=rtpmap:18 G729/8000.

a=fmtp:18 annexb=no.

a=rtpmap:4 G723/8000.

a=fmtp:4 annexa=no.

a=rtpmap:111 G726-32/8000.

a=rtpmap:101 telephone-event/8000.

a=fmtp:101 0-16.

a=silenceSupp:off - - - -.

a=ptime:20.

a=sendrecv.

U 91.121.122.64:5060 -> 212.147.8.99:64041

INVITE sip:41215500335@212.147.8.99:64041 SIP/2.0.

Via: SIP/2.0/UDP 91.121.122.64:5060;branch=z9hG4bK2423d72c;rport.

From: "41215500331" <sip:41215500331@91.121.122.64>;tag=as004f5b87.

To: <sip:41215500335@212.147.8.99:64041>.

Contact: <sip:41215500331@91.121.122.64>.

Call-ID: 7f5db6275e80cb58445b93c840b5881e@91.121.122.64.

CSeq: 102 INVITE.

User-Agent: Asterisk PBX.

Max-Forwards: 70.

Date: Wed, 15 Feb 2012 13:44:38 GMT.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

h323-conf-id: 684267750-1139933510-1735632590-1371098423.

Content-Type: application/sdp.

Content-Length: 388.

.

v=0.

o=root 30924 30924 IN IP4 91.121.122.64.

s=session.

c=IN IP4 91.121.122.64.

t=0 0.

m=audio 27340 RTP/AVP 0 8 18 4 111 101.

a=rtpmap:0 PCMU/8000.

a=rtpmap:8 PCMA/8000.

a=rtpmap:18 G729/8000.

a=fmtp:18 annexb=no.

a=rtpmap:4 G723/8000.

a=fmtp:4 annexa=no.

a=rtpmap:111 G726-32/8000.

a=rtpmap:101 telephone-event/8000.

a=fmtp:101 0-16.

a=silenceSupp:off - - - -.

a=ptime:20.

a=sendrecv.

…

…

U 91.121.122.64:5060 -> 212.147.8.99:64041

CANCEL sip:41215500335@212.147.8.99:64041 SIP/2.0.

Via: SIP/2.0/UDP 91.121.122.64:5060;branch=z9hG4bK2423d72c;rport.

From: "41215500331" <sip:41215500331@91.121.122.64>;tag=as004f5b87.

To: <sip:41215500335@212.147.8.99:64041>.

Call-ID: 7f5db6275e80cb58445b93c840b5881e@91.121.122.64.

CSeq: 102 CANCEL.

User-Agent: Asterisk PBX.

Max-Forwards: 70.

Content-Length: 0.

U 91.121.122.64:5060 -> 178.198.29.66:1028

SIP/2.0 603 Declined.

Via: SIP/2.0/UDP 192.168.1.40:5060;branch=z9hG4bK-cc1c85e0;received=178.198.29.66.

From: "41215500331" <sip:41215500331@astrad.switzernet.com>;tag=dc12daa38c55b708o0.

To: <sip:0215500335@astrad.switzernet.com>;tag=as193071d7.

Call-ID: 7573aff-6487725c@192.168.1.40.

CSeq: 102 INVITE.

User-Agent: Asterisk PBX.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

Contact: <sip:0215500335@91.121.122.64>.

Content-Length: 0.

U 178.198.29.66:1028 -> 91.121.122.64:5060

ACK sip:0215500335@astrad.switzernet.com SIP/2.0.

Via: SIP/2.0/UDP 192.168.1.40:5060;branch=z9hG4bK-cc1c85e0.

From: "41215500331" <sip:41215500331@astrad.switzernet.com>;tag=dc12daa38c55b708o0.

To: <sip:0215500335@astrad.switzernet.com>;tag=as193071d7.

Call-ID: 7573aff-6487725c@192.168.1.40.

CSeq: 102 ACK.

Max-Forwards: 70.

Proxy-Authorization: Digest username="41215500331",realm="switzernet",nonce="23084ccb",uri="sip:0215500335@astrad.switzernet.com",algorithm=MD5,response="b6a1f2a16338e0c5be6b313c2cbaf77a".

Contact: "41215500331" <sip:41215500331@192.168.1.40:5060>.

User-Agent: Linksys/SPA921-5.1.8.

Content-Length: 0.

U 91.121.122.64:5060 -> 212.147.8.99:64041

CANCEL sip:41215500335@212.147.8.99:64041 SIP/2.0.

Via: SIP/2.0/UDP 91.121.122.64:5060;branch=z9hG4bK2423d72c;rport.

From: "41215500331" <sip:41215500331@91.121.122.64>;tag=as004f5b87.

To: <sip:41215500335@212.147.8.99:64041>.

Call-ID: 7f5db6275e80cb58445b93c840b5881e@91.121.122.64.

CSeq: 102 CANCEL.

User-Agent: Asterisk PBX.

Max-Forwards: 70.

Content-Length: 0.

Wireshark file

As we said before, the router filters the SIP traffic modifying the content. As a result, the telephone behind the router is not able to answer the request, in this case INVITE message, breaking the SIP protocol flow and losing the call.

Case 1

As we have done with the outgoing calls, we try to solve the router problem adding a Perl script and a PROXY-SIP server to the scheme.

U 178.198.29.66:1028 -> 91.121.122.64:5060

INVITE sip:0215500335@astrad.switzernet.com SIP/2.0.

Via: SIP/2.0/UDP 192.168.1.40:5060;branch=z9hG4bK-d58fdffd.

From: "41215500331" <sip:41215500331@astrad.switzernet.com>;tag=64d60c09b0e2e81do0.

To: <sip:0215500335@astrad.switzernet.com>.

Call-ID: 850b34b4-498e5f6d@192.168.1.40.

CSeq: 101 INVITE.

Max-Forwards: 70.

Contact: "41215500331" <sip:41215500331@192.168.1.40:5060>.

Expires: 240.

User-Agent: Linksys/SPA921-5.1.8.

Content-Length: 397.

Allow: ACK, BYE, CANCEL, INFO, INVITE, NOTIFY, OPTIONS, REFER.

Supported: replaces.

Content-Type: application/sdp.

.

v=0.

o=- 1309203 1309203 IN IP4 192.168.1.40.

s=-.

c=IN IP4 192.168.1.40.

t=0 0.

m=audio 16416 RTP/AVP 0 2 4 8 18 96 97 98 101.

a=rtpmap:0 PCMU/8000.

a=rtpmap:2 G726-32/8000.

a=rtpmap:4 G723/8000.

a=rtpmap:8 PCMA/8000.

a=rtpmap:18 G729a/8000.

a=rtpmap:96 G726-40/8000.

a=rtpmap:97 G726-24/8000.

a=rtpmap:98 G726-16/8000.

a=rtpmap:101 telephone-event/8000.

a=fmtp:101 0-15.

a=ptime:30.

a=sendrecv.

U 91.121.122.64:5060 -> 178.198.29.66:1028

SIP/2.0 407 Proxy Authentication Required.

Via: SIP/2.0/UDP 192.168.1.40:5060;branch=z9hG4bK-d58fdffd;received=178.198.29.66.

From: "41215500331" <sip:41215500331@astrad.switzernet.com>;tag=64d60c09b0e2e81do0.

To: <sip:0215500335@astrad.switzernet.com>;tag=as1f23f8e5.

Call-ID: 850b34b4-498e5f6d@192.168.1.40.

CSeq: 101 INVITE.

User-Agent: Asterisk PBX.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

Proxy-Authenticate: Digest algorithm=MD5, realm="switzernet", nonce="347cddca".

Content-Length: 0.

U 178.198.29.66:1028 -> 91.121.122.64:5060

ACK sip:0215500335@astrad.switzernet.com SIP/2.0.

Via: SIP/2.0/UDP 192.168.1.40:5060;branch=z9hG4bK-d58fdffd.

From: "41215500331" <sip:41215500331@astrad.switzernet.com>;tag=64d60c09b0e2e81do0.

To: <sip:0215500335@astrad.switzernet.com>;tag=as1f23f8e5.

Call-ID: 850b34b4-498e5f6d@192.168.1.40.

CSeq: 101 ACK.

Max-Forwards: 70.

Contact: "41215500331" <sip:41215500331@192.168.1.40:5060>.

User-Agent: Linksys/SPA921-5.1.8.

Content-Length: 0.

U 178.198.29.66:1028 -> 91.121.122.64:5060

INVITE sip:0215500335@astrad.switzernet.com SIP/2.0.

Via: SIP/2.0/UDP 192.168.1.40:5060;branch=z9hG4bK-29ae86cd.

From: "41215500331" <sip:41215500331@astrad.switzernet.com>;tag=64d60c09b0e2e81do0.

To: <sip:0215500335@astrad.switzernet.com>.

Call-ID: 850b34b4-498e5f6d@192.168.1.40.

CSeq: 102 INVITE.

Max-Forwards: 70.

Proxy-Authorization: Digest username="41215500331",realm="switzernet",nonce="347cddca",uri="sip:0215500335@astrad.switzernet.com",algorithm=MD5,response="14b916c39c0330859e2f1adbd4342ccb".

Contact: "41215500331" <sip:41215500331@192.168.1.40:5060>.

Expires: 240.

User-Agent: Linksys/SPA921-5.1.8.

Content-Length: 397.

Allow: ACK, BYE, CANCEL, INFO, INVITE, NOTIFY, OPTIONS, REFER.

Supported: replaces.

Content-Type: application/sdp.

.

v=0.

o=- 1309203 1309203 IN IP4 192.168.1.40.

s=-.

c=IN IP4 192.168.1.40.

t=0 0.

m=audio 16416 RTP/AVP 0 2 4 8 18 96 97 98 101.

a=rtpmap:0 PCMU/8000.

a=rtpmap:2 G726-32/8000.

a=rtpmap:4 G723/8000.

a=rtpmap:8 PCMA/8000.

a=rtpmap:18 G729a/8000.

a=rtpmap:96 G726-40/8000.

a=rtpmap:97 G726-24/8000.

a=rtpmap:98 G726-16/8000.

a=rtpmap:101 telephone-event/8000.

a=fmtp:101 0-15.

a=ptime:30.

a=sendrecv.

U 91.121.122.64:5060 -> 178.198.29.66:1028

SIP/2.0 100 Trying.

Via: SIP/2.0/UDP 192.168.1.40:5060;branch=z9hG4bK-29ae86cd;received=178.198.29.66.

From: "41215500331" <sip:41215500331@astrad.switzernet.com>;tag=64d60c09b0e2e81do0.

To: <sip:0215500335@astrad.switzernet.com>.

Call-ID: 850b34b4-498e5f6d@192.168.1.40.

CSeq: 102 INVITE.

User-Agent: Asterisk PBX.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

Contact: <sip:0215500335@91.121.122.64>.

Content-Length: 0.

U 91.121.122.64:5060 -> 178.198.29.66:1028

SIP/2.0 183 Session Progress.

Via: SIP/2.0/UDP 192.168.1.40:5060;branch=z9hG4bK-29ae86cd;received=178.198.29.66.

From: "41215500331" <sip:41215500331@astrad.switzernet.com>;tag=64d60c09b0e2e81do0.

To: <sip:0215500335@astrad.switzernet.com>;tag=as685348b7.

Call-ID: 850b34b4-498e5f6d@192.168.1.40.

CSeq: 102 INVITE.

User-Agent: Asterisk PBX.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

Contact: <sip:0215500335@91.121.122.64>.

Content-Type: application/sdp.

Content-Length: 384.

.

v=0.

o=root 30924 30924 IN IP4 91.121.122.64.

s=session.

c=IN IP4 91.121.122.64.

t=0 0.

m=audio 28178 RTP/AVP 0 8 18 4 2 101.

a=rtpmap:0 PCMU/8000.

a=rtpmap:8 PCMA/8000.

a=rtpmap:18 G729/8000.

a=fmtp:18 annexb=no.

a=rtpmap:4 G723/8000.

a=fmtp:4 annexa=no.

a=rtpmap:2 G726-32/8000.

a=rtpmap:101 telephone-event/8000.

a=fmtp:101 0-16.

a=silenceSupp:off - - - -.

a=ptime:20.

a=sendrecv.

U 91.121.122.64:5081 -> 212.147.8.99:64041

INVITE sip:41215500335@91.121.122.64:5080 SIP/2.0.

Via: SIP/2.0/UDP 91.121.122.64:5081;branch=z9hG4bK-0237e4a5123.

Via: SIP/2.0/UDP 91.121.122.64:5060;branch=z9hG4bK0237e4a5;rport.

From: "41215500331" <sip:41215500331@91.121.122.64>;tag=as2c29b342.

To: <sip:41215500335@91.121.122.64:5080>.

Contact: <sip:91.121.122.64>.

Call-ID: 2784660e1aff375a457ad56949ff8d06@91.121.122.64.

CSeq: 102 INVITE.

User-Agent: Asterisk PBX.

Max-Forwards: 70.

Date: Wed, 15 Feb 2012 13:46:09 GMT.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

X-Astrad-RPL: 212.147.8.99:64041.

X-Astrad-RP: 1.

X-Astrad-SA: 1.

h323-conf-id: 303732657-580781950-566473457-1260074105.

Content-Type: application/sdp.

Content-Length: 388.

.

v=0.

o=root 30924 30924 IN IP4 91.121.122.64.

s=session.

c=IN IP4 91.121.122.64.

t=0 0.

m=audio 15496 RTP/AVP 0 8 18 4 111 101.

a=rtpmap:0 PCMU/8000.

a=rtpmap:8 PCMA/8000.

a=rtpmap:18 G729/8000.

a=fmtp:18 annexb=no.

a=rtpmap:4 G723/8000.

a=fmtp:4 annexa=no.

a=rtpmap:111 G726-32/8000.

a=rtpmap:101 telephone-event/8000.

a=fmtp:101 0-16.

a=silenceSupp:off - - - -.

a=ptime:20.

a=sendrecv.

U 212.147.8.99:64041 -> 91.121.122.64:5081

SIP/2.0 100 Trying.

Via: SIP/2.0/UDP 91.121.122.64:5081;branch=z9hG4bK-0237e4a5123.

Via: SIP/2.0/UDP 91.121.122.64:5060;branch=z9hG4bK0237e4a5;rport.

From: "41215500331" <sip:41215500331@91.121.122.64>;tag=as2c29b342.

To: <sip:41215500335@91.121.122.64:5080>.

Call-ID: 2784660e1aff375a457ad56949ff8d06@91.121.122.64:5081.

CSeq: 102 INVITE.

Supported: replaces, path, timer.

User-Agent: Grandstream GXP1100 1.0.1.83.

Allow: INVITE, ACK, OPTIONS, CANCEL, BYE, SUBSCRIBE, NOTIFY, INFO, REFER, UPDATE, MESSAGE.

Content-Length: 0.

Note: this message doesn’t appear on the Wireshark datagram.

U 212.147.8.99:64041 -> 91.121.122.64:5081

SIP/2.0 180 Ringing.

Via: SIP/2.0/UDP 91.121.122.64:5081;branch=z9hG4bK-0237e4a5123.

Via: SIP/2.0/UDP 91.121.122.64:5060;branch=z9hG4bK0237e4a5;rport.

From: "41215500331" <sip:41215500331@91.121.122.64>;tag=as2c29b342.

To: <sip:41215500335@91.121.122.64:5080>;tag=1657381872.

Call-ID: 2784660e1aff375a457ad56949ff8d06@91.121.122.64:5081.

CSeq: 102 INVITE.

Contact: <sip:41215500335@91.121.122.64:5081>.

Supported: replaces, path, timer.

User-Agent: Grandstream GXP1100 1.0.1.83.

Allow-Events: talk, hold.

Allow: INVITE, ACK, OPTIONS, CANCEL, BYE, SUBSCRIBE, NOTIFY, INFO, REFER, UPDATE, MESSAGE.

Content-Length: 0.

Note: this message doesn’t appear on the Wireshark datagram.

U 91.121.122.64:5060 -> 178.198.29.66:1028

SIP/2.0 180 Ringing.

Via: SIP/2.0/UDP 192.168.1.40:5060;branch=z9hG4bK-29ae86cd;received=178.198.29.66.

From: "41215500331" <sip:41215500331@astrad.switzernet.com>;tag=64d60c09b0e2e81do0.

To: <sip:0215500335@astrad.switzernet.com>;tag=as685348b7.

Call-ID: 850b34b4-498e5f6d@192.168.1.40.

CSeq: 102 INVITE.

User-Agent: Asterisk PBX.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

Contact: <sip:0215500335@91.121.122.64>.

Content-Length: 0.

U 212.147.8.99:64041 -> 91.121.122.64:5081

SIP/2.0 200 OK.

Via: SIP/2.0/UDP 91.121.122.64:5081;branch=z9hG4bK-0237e4a5123.

Via: SIP/2.0/UDP 91.121.122.64:5060;branch=z9hG4bK0237e4a5;rport.

From: "41215500331" <sip:41215500331@91.121.122.64>;tag=as2c29b342.

To: <sip:41215500335@91.121.122.64:5080>;tag=1657381872.

Call-ID: 2784660e1aff375a457ad56949ff8d06@91.121.122.64:5081.

CSeq: 102 INVITE.

Contact: <sip:41215500335@91.121.122.64:5081>.

Supported: replaces, path, timer.

User-Agent: Grandstream GXP1100 1.0.1.83.

Allow: INVITE, ACK, OPTIONS, CANCEL, BYE, SUBSCRIBE, NOTIFY, INFO, REFER, UPDATE, MESSAGE.

Content-Type: application/sdp.

Content-Length:   383.

.

v=0.

o=41215500335 8000 8000 IN IP4 10.0.0.8.

s=SIP Call.

c=IN IP4 10.0.0.8.

t=0 0.

m=audio 5004 RTP/AVP 0 8 18 4 111 101.

a=sendrecv.

a=rtpmap:0 PCMU/8000.

a=ptime:20.

a=rtpmap:8 PCMA/8000.

a=rtpmap:18 G729/8000.

a=fmtp:18 annexb=no.

a=rtpmap:4 G723/8000.

a=fmtp:4 annexa=no.

a=rtpmap:111 G726-32/8000.

a=rtpmap:101 telephone-event/8000.

a=fmtp:101 0-15.

a=silenceSupp:off - - - -.

Note: this message doesn’t appear on the Wireshark datagram.

U 91.121.122.64:5060 -> 178.198.29.66:1028

SIP/2.0 200 OK.

Via: SIP/2.0/UDP 192.168.1.40:5060;branch=z9hG4bK-29ae86cd;received=178.198.29.66.

From: "41215500331" <sip:41215500331@astrad.switzernet.com>;tag=64d60c09b0e2e81do0.

To: <sip:0215500335@astrad.switzernet.com>;tag=as685348b7.

Call-ID: 850b34b4-498e5f6d@192.168.1.40.

CSeq: 102 INVITE.

User-Agent: Asterisk PBX.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

Contact: <sip:0215500335@91.121.122.64>.

Content-Type: application/sdp.

Content-Length: 384.

.

v=0.

o=root 30924 30925 IN IP4 91.121.122.64.

s=session.

c=IN IP4 91.121.122.64.

t=0 0.

m=audio 28178 RTP/AVP 0 8 18 4 2 101.

a=rtpmap:0 PCMU/8000.

a=rtpmap:8 PCMA/8000.

a=rtpmap:18 G729/8000.

a=fmtp:18 annexb=no.

a=rtpmap:4 G723/8000.

a=fmtp:4 annexa=no.

a=rtpmap:2 G726-32/8000.

a=rtpmap:101 telephone-event/8000.

a=fmtp:101 0-16.

a=silenceSupp:off - - - -.

a=ptime:20.

a=sendrecv.

U 91.121.122.64:5081 -> 212.147.8.99:64041

ACK sip:41215500335@91.121.122.64:5080 SIP/2.0.

Via: SIP/2.0/UDP 91.121.122.64:5081;branch=z9hG4bK-3952c159123.

Via: SIP/2.0/UDP 91.121.122.64:5060;branch=z9hG4bK3952c159;rport.

From: "41215500331" <sip:41215500331@91.121.122.64>;tag=as2c29b342.

To: <sip:41215500335@91.121.122.64:5080>;tag=1657381872.

Contact: <sip:91.121.122.64>.

Call-ID: 2784660e1aff375a457ad56949ff8d06@91.121.122.64.

CSeq: 102 ACK.

User-Agent: Asterisk PBX.

Max-Forwards: 70.

Content-Length: 0.

U 178.198.29.66:1028 -> 91.121.122.64:5060

ACK sip:0215500335@91.121.122.64 SIP/2.0.

Via: SIP/2.0/UDP 192.168.1.40:5060;branch=z9hG4bK-87b50f22.

From: "41215500331" <sip:41215500331@astrad.switzernet.com>;tag=64d60c09b0e2e81do0.

To: <sip:0215500335@astrad.switzernet.com>;tag=as685348b7.

Call-ID: 850b34b4-498e5f6d@192.168.1.40.

CSeq: 102 ACK.

Max-Forwards: 70.

Proxy-Authorization: Digest username="41215500331",realm="switzernet",nonce="347cddca",uri="sip:0215500335@astrad.switzernet.com",algorithm=MD5,response="14b916c39c0330859e2f1adbd4342ccb".

Contact: "41215500331" <sip:41215500331@192.168.1.40:5060>.

User-Agent: Linksys/SPA921-5.1.8.

Content-Length: 0.

U 212.147.8.99:64041 -> 91.121.122.64:5060

BYE sip:91.121.122.64 SIP/2.0.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK1352535809;rport.

From: <sip:41215500335@91.121.122.64:5080>;tag=1657381872.

To: "41215500331" <sip:41215500331@91.121.122.64>;tag=as2c29b342.

Call-ID: 2784660e1aff375a457ad56949ff8d06@91.121.122.64:5081.

CSeq: 103 BYE.

Contact: <sip:41215500335@192.168.1.132:5060>.

Max-Forwards: 70.

Supported: replaces, path, timer.

User-Agent: Grandstream GXP1100 1.0.1.83.

Allow: INVITE, ACK, OPTIONS, CANCEL, BYE, SUBSCRIBE, NOTIFY, INFO, REFER, UPDATE, MESSAGE.

Content-Length: 0.

Note: this message doesn’t appear on the Wireshark datagram.

U 91.121.122.64:5060 -> 212.147.8.99:64041

SIP/2.0 481 Call leg/transaction does not exist.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK1352535809;received=212.147.8.99;rport=64041.

From: <sip:41215500335@91.121.122.64:5080>;tag=1657381872.

To: "41215500331" <sip:41215500331@91.121.122.64>;tag=as2c29b342.

Call-ID: 2784660e1aff375a457ad56949ff8d06@91.121.122.64:5081.

CSeq: 103 BYE.

User-Agent: Asterisk PBX.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

Content-Length: 0.

Note: this message doesn’t appear on the Wireshark datagram.

U 178.198.29.66:1028 -> 91.121.122.64:5060

BYE sip:0215500335@91.121.122.64 SIP/2.0.

Via: SIP/2.0/UDP 192.168.1.40:5060;branch=z9hG4bK-a713d572.

From: "41215500331" <sip:41215500331@astrad.switzernet.com>;tag=64d60c09b0e2e81do0.

To: <sip:0215500335@astrad.switzernet.com>;tag=as685348b7.

Call-ID: 850b34b4-498e5f6d@192.168.1.40.

CSeq: 103 BYE.

Max-Forwards: 70.

Proxy-Authorization: Digest username="41215500331",realm="switzernet",nonce="347cddca",uri="sip:0215500335@91.121.122.64",algorithm=MD5,response="9f89fd5766c0dd9932c2d2b32b518a18".

User-Agent: Linksys/SPA921-5.1.8.

Content-Length: 0.

U 91.121.122.64:5060 -> 178.198.29.66:1028

SIP/2.0 200 OK.

Via: SIP/2.0/UDP 192.168.1.40:5060;branch=z9hG4bK-a713d572;received=178.198.29.66.

From: "41215500331" <sip:41215500331@astrad.switzernet.com>;tag=64d60c09b0e2e81do0.

To: <sip:0215500335@astrad.switzernet.com>;tag=as685348b7.

Call-ID: 850b34b4-498e5f6d@192.168.1.40.

CSeq: 103 BYE.

User-Agent: Asterisk PBX.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

Contact: <sip:0215500335@91.121.122.64>.

Content-Length: 0.

U 91.121.122.64:5081 -> 212.147.8.99:64041

BYE sip:41215500335@91.121.122.64:5080 SIP/2.0.

Via: SIP/2.0/UDP 91.121.122.64:5081;branch=z9hG4bK-7f9aeda7123.

Via: SIP/2.0/UDP 91.121.122.64:5060;branch=z9hG4bK7f9aeda7;rport.

From: "41215500331" <sip:41215500331@91.121.122.64>;tag=as2c29b342.

To: <sip:41215500335@91.121.122.64:5080>;tag=1657381872.

Call-ID: 2784660e1aff375a457ad56949ff8d06@91.121.122.64.

CSeq: 103 BYE.

User-Agent: Asterisk PBX.

Max-Forwards: 70.

Content-Length: 0.

U 212.147.8.99:64041 -> 91.121.122.64:5081

SIP/2.0 481 Call Leg/Transaction Does Not Exist.

Via: SIP/2.0/UDP 91.121.122.64:5081;branch=z9hG4bK-7f9aeda7123.

Via: SIP/2.0/UDP 91.121.122.64:5060;branch=z9hG4bK7f9aeda7;rport.

From: "41215500331" <sip:41215500331@91.121.122.64>;tag=as2c29b342.

To: <sip:41215500335@91.121.122.64:5080>;tag=1657381872.

Call-ID: 2784660e1aff375a457ad56949ff8d06@91.121.122.64.

CSeq: 103 BYE.

Supported: replaces, path, timer.

User-Agent: Grandstream GXP1100 1.0.1.83.

Allow: INVITE, ACK, OPTIONS, CANCEL, BYE, SUBSCRIBE, NOTIFY, INFO, REFER, UPDATE, MESSAGE.

Content-Length: 0.

Wireshark file

As consequence of the treatment that the router performs over the SIP traffic, we have now the following situation:

· Message that arrives from the ASTRAD server to the destination phone, for example, INVITE:

Call-ID: 2784660e1aff375a457ad56949ff8d06@91.121.122.64.

· Messages that the destination phone answers to the SIP server (TRYING and RINGING):

Call-ID: 2784660e1aff375a457ad56949ff8d06@91.121.122.64:5081.

We can see that the router adds the port number at the end of the Call-ID. This cause that when the message reaches the SIP server, it is understood as a different call and the ASTRAD server doesn’t consider it as an answer to the previous request message.

Case 2

Trying to solve the problem that we have with incoming calls in “Case 1”, we use another Perl script configuration.

U 178.198.29.66:1028 -> 91.121.122.64:5060

INVITE sip:0215500335@astrad.switzernet.com SIP/2.0.

Via: SIP/2.0/UDP 192.168.1.40:5060;branch=z9hG4bK-1e56d643.

From: "41215500331" <sip:41215500331@astrad.switzernet.com>;tag=1ac91f984acedd2o0.

To: <sip:0215500335@astrad.switzernet.com>.

Call-ID: f2a4df90-ab276e3a@192.168.1.40.

CSeq: 101 INVITE.

Max-Forwards: 70.

Contact: "41215500331" <sip:41215500331@192.168.1.40:5060>.

Expires: 240.

User-Agent: Linksys/SPA921-5.1.8.

Content-Length: 397.

Allow: ACK, BYE, CANCEL, INFO, INVITE, NOTIFY, OPTIONS, REFER.

Supported: replaces.

Content-Type: application/sdp.

.

v=0.

o=- 1316363 1316363 IN IP4 192.168.1.40.

s=-.

c=IN IP4 192.168.1.40.

t=0 0.

m=audio 16418 RTP/AVP 0 2 4 8 18 96 97 98 101.

a=rtpmap:0 PCMU/8000.

a=rtpmap:2 G726-32/8000.

a=rtpmap:4 G723/8000.

a=rtpmap:8 PCMA/8000.

a=rtpmap:18 G729a/8000.

a=rtpmap:96 G726-40/8000.

a=rtpmap:97 G726-24/8000.

a=rtpmap:98 G726-16/8000.

a=rtpmap:101 telephone-event/8000.

a=fmtp:101 0-15.

a=ptime:30.

a=sendrecv.

U 91.121.122.64:5060 -> 178.198.29.66:1028

SIP/2.0 407 Proxy Authentication Required.

Via: SIP/2.0/UDP 192.168.1.40:5060;branch=z9hG4bK-1e56d643;received=178.198.29.66.

From: "41215500331" <sip:41215500331@astrad.switzernet.com>;tag=1ac91f984acedd2o0.

To: <sip:0215500335@astrad.switzernet.com>;tag=as201538be.

Call-ID: f2a4df90-ab276e3a@192.168.1.40.

CSeq: 101 INVITE.

User-Agent: Asterisk PBX.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

Proxy-Authenticate: Digest algorithm=MD5, realm="switzernet", nonce="1fff0316".

Content-Length: 0.

U 178.198.29.66:1028 -> 91.121.122.64:5060

ACK sip:0215500335@astrad.switzernet.com SIP/2.0.

Via: SIP/2.0/UDP 192.168.1.40:5060;branch=z9hG4bK-1e56d643.

From: "41215500331" <sip:41215500331@astrad.switzernet.com>;tag=1ac91f984acedd2o0.

To: <sip:0215500335@astrad.switzernet.com>;tag=as201538be.

Call-ID: f2a4df90-ab276e3a@192.168.1.40.

CSeq: 101 ACK.

Max-Forwards: 70.

Contact: "41215500331" <sip:41215500331@192.168.1.40:5060>.

User-Agent: Linksys/SPA921-5.1.8.

Content-Length: 0.

U 178.198.29.66:1028 -> 91.121.122.64:5060

INVITE sip:0215500335@astrad.switzernet.com SIP/2.0.

Via: SIP/2.0/UDP 192.168.1.40:5060;branch=z9hG4bK-883c6b64.

From: "41215500331" <sip:41215500331@astrad.switzernet.com>;tag=1ac91f984acedd2o0.

To: <sip:0215500335@astrad.switzernet.com>.

Call-ID: f2a4df90-ab276e3a@192.168.1.40.

CSeq: 102 INVITE.

Max-Forwards: 70.

Proxy-Authorization: Digest username="41215500331",realm="switzernet",nonce="1fff0316",uri="sip:0215500335@astrad.switzernet.com",algorithm=MD5,response="96b2a6db74fbbcaf1047c30c747d1cc4".

Contact: "41215500331" <sip:41215500331@192.168.1.40:5060>.

Expires: 240.

User-Agent: Linksys/SPA921-5.1.8.

Content-Length: 397.

Allow: ACK, BYE, CANCEL, INFO, INVITE, NOTIFY, OPTIONS, REFER.

Supported: replaces.

Content-Type: application/sdp.

.

v=0.

o=- 1316363 1316363 IN IP4 192.168.1.40.

s=-.

c=IN IP4 192.168.1.40.

t=0 0.

m=audio 16418 RTP/AVP 0 2 4 8 18 96 97 98 101.

a=rtpmap:0 PCMU/8000.

a=rtpmap:2 G726-32/8000.

a=rtpmap:4 G723/8000.

a=rtpmap:8 PCMA/8000.

a=rtpmap:18 G729a/8000.

a=rtpmap:96 G726-40/8000.

a=rtpmap:97 G726-24/8000.

a=rtpmap:98 G726-16/8000.

a=rtpmap:101 telephone-event/8000.

a=fmtp:101 0-15.

a=ptime:30.

a=sendrecv.

U 91.121.122.64:5060 -> 178.198.29.66:1028

SIP/2.0 100 Trying.

Via: SIP/2.0/UDP 192.168.1.40:5060;branch=z9hG4bK-883c6b64;received=178.198.29.66.

From: "41215500331" <sip:41215500331@astrad.switzernet.com>;tag=1ac91f984acedd2o0.

To: <sip:0215500335@astrad.switzernet.com>.

Call-ID: f2a4df90-ab276e3a@192.168.1.40.

CSeq: 102 INVITE.

User-Agent: Asterisk PBX.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

Contact: <sip:0215500335@91.121.122.64>.

Content-Length: 0.

U 91.121.122.64:5060 -> 178.198.29.66:1028

SIP/2.0 183 Session Progress.

Via: SIP/2.0/UDP 192.168.1.40:5060;branch=z9hG4bK-883c6b64;received=178.198.29.66.

From: "41215500331" <sip:41215500331@astrad.switzernet.com>;tag=1ac91f984acedd2o0.

To: <sip:0215500335@astrad.switzernet.com>;tag=as3a111a77.

Call-ID: f2a4df90-ab276e3a@192.168.1.40.

CSeq: 102 INVITE.

User-Agent: Asterisk PBX.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

Contact: <sip:0215500335@91.121.122.64>.

Content-Type: application/sdp.

Content-Length: 384.

.

v=0.

o=root 30924 30924 IN IP4 91.121.122.64.

s=session.

c=IN IP4 91.121.122.64.

t=0 0.

m=audio 30490 RTP/AVP 0 8 18 4 2 101.

a=rtpmap:0 PCMU/8000.

a=rtpmap:8 PCMA/8000.

a=rtpmap:18 G729/8000.

a=fmtp:18 annexb=no.

a=rtpmap:4 G723/8000.

a=fmtp:4 annexa=no.

a=rtpmap:2 G726-32/8000.

a=rtpmap:101 telephone-event/8000.

a=fmtp:101 0-16.

a=silenceSupp:off - - - -.

a=ptime:20.

a=sendrecv.

U 91.121.122.64:5060 -> 212.147.8.99:62739

INVITE sip:41215500335@91.121.122.64:5080 SIP/2.0.

Via: SIP/2.0/UDP 91.121.122.64:5081;branch=z9hG4bK-586d1d07123.

Via: SIP/2.0/UDP 91.121.122.64:5060;branch=z9hG4bK586d1d07;rport.

From: "41215500331" <sip:41215500331@91.121.122.64>;tag=as3730b746.

To: <sip:41215500335@91.121.122.64:5080>.

Contact: <sip:91.121.122.64>.

Call-ID: 398ac09819ffa59a29ce5c6e127ba01e@91.121.122.64:5081

CSeq: 102 INVITE.

User-Agent: Asterisk PBX.

Max-Forwards: 70.

Date: Wed, 15 Feb 2012 10:57:12 GMT.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

X-Astrad-RPL: 212.147.8.99:62739.

X-Astrad-RP: 1.

X-Astrad-SA: 2.

h323-conf-id: 1859935200-401118528-370583092-1434973912.

Content-Type: application/sdp.

Content-Length: 387.

.

v=0.

o=root 30924 30924 IN IP4 91.121.122.64.

s=session.

c=IN IP4 91.121.122.64.

t=0 0.

m=audio 9826 RTP/AVP 0 8 18 4 111 101.

a=rtpmap:0 PCMU/8000.

a=rtpmap:8 PCMA/8000.

a=rtpmap:18 G729/8000.

a=fmtp:18 annexb=no.

a=rtpmap:4 G723/8000.

a=fmtp:4 annexa=no.

a=rtpmap:111 G726-32/8000.

a=rtpmap:101 telephone-event/8000.

a=fmtp:101 0-16.

a=silenceSupp:off - - - -.

a=ptime:20.

a=sendrecv.

U 212.147.8.99:64041 -> 91.121.122.64:5081

SIP/2.0 100 Trying.

Via: SIP/2.0/UDP 91.121.122.64:5081;branch=z9hG4bK-0a857df2123.

Via: SIP/2.0/UDP 91.121.122.64:5060;branch=z9hG4bK0a857df2;rport.

From: "41215500331" <sip:41215500331@91.121.122.64>;tag=as47fdfeeb.

To: <sip:41215500335@91.121.122.64:5080>.

Call-ID: 1c6d63870c67e54d28b488e059a696f5@91.121.122.64:5081.

CSeq: 102 INVITE.

Supported: replaces, path, timer.

User-Agent: Grandstream GXP1100 1.0.1.83.

Allow: INVITE, ACK, OPTIONS, CANCEL, BYE, SUBSCRIBE, NOTIFY, INFO, REFER, UPDATE, MESSAGE.

Content-Length: 0.

U 212.147.8.99:64041 -> 91.121.122.64:5081

SIP/2.0 180 Ringing.

Via: SIP/2.0/UDP 91.121.122.64:5081;branch=z9hG4bK-0a857df2123.

Via: SIP/2.0/UDP 91.121.122.64:5060;branch=z9hG4bK0a857df2;rport.

From: "41215500331" <sip:41215500331@91.121.122.64>;tag=as47fdfeeb.

To: <sip:41215500335@91.121.122.64:5080>;tag=225611292.

Call-ID: 1c6d63870c67e54d28b488e059a696f5@91.121.122.64:5081.

CSeq: 102 INVITE.

Contact: <sip:41215500335@91.121.122.64:5081>.

Supported: replaces, path, timer.

User-Agent: Grandstream GXP1100 1.0.1.83.

Allow-Events: talk, hold.

Allow: INVITE, ACK, OPTIONS, CANCEL, BYE, SUBSCRIBE, NOTIFY, INFO, REFER, UPDATE, MESSAGE.

Content-Length: 0.

U 91.121.122.64:5060 -> 178.198.29.66:1028

SIP/2.0 180 Ringing.

Via: SIP/2.0/UDP 192.168.1.40:5060;branch=z9hG4bK-883c6b64;received=178.198.29.66.

From: "41215500331" <sip:41215500331@astrad.switzernet.com>;tag=1ac91f984acedd2o0.

To: <sip:0215500335@astrad.switzernet.com>;tag=as3a111a77.

Call-ID: f2a4df90-ab276e3a@192.168.1.40.

CSeq: 102 INVITE.

User-Agent: Asterisk PBX.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

Contact: <sip:0215500335@91.121.122.64>.

Content-Length: 0.

U 212.147.8.99:64041 -> 91.121.122.64:5081

SIP/2.0 200 OK.

Via: SIP/2.0/UDP 91.121.122.64:5081;branch=z9hG4bK-0a857df2123.

Via: SIP/2.0/UDP 91.121.122.64:5060;branch=z9hG4bK0a857df2;rport.

From: "41215500331" <sip:41215500331@91.121.122.64>;tag=as47fdfeeb.

To: <sip:41215500335@91.121.122.64:5080>;tag=225611292.

Call-ID: 1c6d63870c67e54d28b488e059a696f5@91.121.122.64:5081.

CSeq: 102 INVITE.

Contact: <sip:41215500335@91.121.122.64:5081>.

Supported: replaces, path, timer.

User-Agent: Grandstream GXP1100 1.0.1.83.

Allow: INVITE, ACK, OPTIONS, CANCEL, BYE, SUBSCRIBE, NOTIFY, INFO, REFER, UPDATE, MESSAGE.

Content-Type: application/sdp.

Content-Length:   383.

.

v=0.

o=41215500335 8000 8000 IN IP4 10.0.0.8.

s=SIP Call.

c=IN IP4 10.0.0.8.

t=0 0.

m=audio 5004 RTP/AVP 0 8 18 4 111 101.

a=sendrecv.

a=rtpmap:0 PCMU/8000.

a=ptime:20.

a=rtpmap:8 PCMA/8000.

a=rtpmap:18 G729/8000.

a=fmtp:18 annexb=no.

a=rtpmap:4 G723/8000.

a=fmtp:4 annexa=no.

a=rtpmap:111 G726-32/8000.

a=rtpmap:101 telephone-event/8000.

a=fmtp:101 0-15.

a=silenceSupp:off - - - -.

U 91.121.122.64:5060 -> 178.198.29.66:1028

SIP/2.0 200 OK.

Via: SIP/2.0/UDP 192.168.1.40:5060;branch=z9hG4bK-883c6b64;received=178.198.29.66.

From: "41215500331" <sip:41215500331@astrad.switzernet.com>;tag=1ac91f984acedd2o0.

To: <sip:0215500335@astrad.switzernet.com>;tag=as3a111a77.

Call-ID: f2a4df90-ab276e3a@192.168.1.40.

CSeq: 102 INVITE.

User-Agent: Asterisk PBX.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

Contact: <sip:0215500335@91.121.122.64>.

Content-Type: application/sdp.

Content-Length: 384.

.

v=0.

o=root 30924 30925 IN IP4 91.121.122.64.

s=session.

c=IN IP4 91.121.122.64.

t=0 0.

m=audio 30490 RTP/AVP 0 8 18 4 2 101.

a=rtpmap:0 PCMU/8000.

a=rtpmap:8 PCMA/8000.

a=rtpmap:18 G729/8000.

a=fmtp:18 annexb=no.

a=rtpmap:4 G723/8000.

a=fmtp:4 annexa=no.

a=rtpmap:2 G726-32/8000.

a=rtpmap:101 telephone-event/8000.

a=fmtp:101 0-16.

a=silenceSupp:off - - - -.

a=ptime:20.

a=sendrecv.

U 91.121.122.64:5060 -> 212.147.8.99:64041

ACK sip:41215500335@91.121.122.64:5080 SIP/2.0.

Via: SIP/2.0/UDP 91.121.122.64:5081;branch=z9hG4bK-294ec707123.

Via: SIP/2.0/UDP 91.121.122.64:5060;branch=z9hG4bK294ec707;rport.

From: "41215500331" <sip:41215500331@91.121.122.64>;tag=as47fdfeeb.

To: <sip:41215500335@91.121.122.64:5080>;tag=225611292.

Contact: <sip:91.121.122.64>.

Call-ID: 1c6d63870c67e54d28b488e059a696f5@91.121.122.64:5081

CSeq: 102 ACK.

User-Agent: Asterisk PBX.

Max-Forwards: 70.

Content-Length: 0.

U 178.198.29.66:1028 -> 91.121.122.64:5060

ACK sip:0215500335@91.121.122.64 SIP/2.0.

Via: SIP/2.0/UDP 192.168.1.40:5060;branch=z9hG4bK-eace5808.

From: "41215500331" <sip:41215500331@astrad.switzernet.com>;tag=1ac91f984acedd2o0.

To: <sip:0215500335@astrad.switzernet.com>;tag=as3a111a77.

Call-ID: f2a4df90-ab276e3a@192.168.1.40.

CSeq: 102 ACK.

Max-Forwards: 70.

Proxy-Authorization: Digest username="41215500331",realm="switzernet",nonce="1fff0316",uri="sip:0215500335@astrad.switzernet.com",algorithm=MD5,response="96b2a6db74fbbcaf1047c30c747d1cc4".

Contact: "41215500331" <sip:41215500331@192.168.1.40:5060>.

User-Agent: Linksys/SPA921-5.1.8.

Content-Length: 0.

U 212.147.8.99:64041 -> 91.121.122.64:5060

BYE sip:91.121.122.64 SIP/2.0.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK855825212;rport.

From: <sip:41215500335@91.121.122.64:5080>;tag=225611292.

To: "41215500331" <sip:41215500331@91.121.122.64>;tag=as47fdfeeb.

Call-ID: 1c6d63870c67e54d28b488e059a696f5@91.121.122.64:5081.

CSeq: 103 BYE.

Contact: <sip:41215500335@192.168.1.132:5060>.

Max-Forwards: 70.

Supported: replaces, path, timer.

User-Agent: Grandstream GXP1100 1.0.1.83.

Allow: INVITE, ACK, OPTIONS, CANCEL, BYE, SUBSCRIBE, NOTIFY, INFO, REFER, UPDATE, MESSAGE.

Content-Length: 0.

U 91.121.122.64:5060 -> 212.147.8.99:64041

SIP/2.0 481 Call leg/transaction does not exist.

Via: SIP/2.0/UDP 192.168.1.132:5060;branch=z9hG4bK855825212;received=212.147.8.99;rport=64041.

From: <sip:41215500335@91.121.122.64:5080>;tag=225611292.

To: "41215500331" <sip:41215500331@91.121.122.64>;tag=as47fdfeeb.

Call-ID: 1c6d63870c67e54d28b488e059a696f5@91.121.122.64:5081.

CSeq: 103 BYE.

User-Agent: Asterisk PBX.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

Content-Length: 0.

U 178.198.29.66:1028 -> 91.121.122.64:5060

BYE sip:0215500335@91.121.122.64 SIP/2.0.

Via: SIP/2.0/UDP 192.168.1.40:5060;branch=z9hG4bK-b9d80a5.

From: "41215500331" <sip:41215500331@astrad.switzernet.com>;tag=1ac91f984acedd2o0.

To: <sip:0215500335@astrad.switzernet.com>;tag=as3a111a77.

Call-ID: f2a4df90-ab276e3a@192.168.1.40.

CSeq: 103 BYE.

Max-Forwards: 70.

Proxy-Authorization: Digest username="41215500331",realm="switzernet",nonce="1fff0316",uri="sip:0215500335@91.121.122.64",algorithm=MD5,response="cce5b64649e738d86adff78f29af940a".

User-Agent: Linksys/SPA921-5.1.8.

Content-Length: 0.

U 91.121.122.64:5060 -> 178.198.29.66:1028

SIP/2.0 200 OK.

Via: SIP/2.0/UDP 192.168.1.40:5060;branch=z9hG4bK-b9d80a5;received=178.198.29.66.

From: "41215500331" <sip:41215500331@astrad.switzernet.com>;tag=1ac91f984acedd2o0.

To: <sip:0215500335@astrad.switzernet.com>;tag=as3a111a77.

Call-ID: f2a4df90-ab276e3a@192.168.1.40.

CSeq: 103 BYE.

User-Agent: Asterisk PBX.

Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY.

Supported: replaces.

Contact: <sip:0215500335@91.121.122.64>.

Content-Length: 0.

U 91.121.122.64:5060 -> 212.147.8.99:64041

BYE sip:41215500335@91.121.122.64:5080 SIP/2.0.

Via: SIP/2.0/UDP 91.121.122.64:5081;branch=z9hG4bK-62ea813d123.

Via: SIP/2.0/UDP 91.121.122.64:5060;branch=z9hG4bK62ea813d;rport.

From: "41215500331" <sip:41215500331@91.121.122.64>;tag=as47fdfeeb.

To: <sip:41215500335@91.121.122.64:5080>;tag=225611292.

Call-ID: 1c6d63870c67e54d28b488e059a696f5@91.121.122.64.

CSeq: 103 BYE.

User-Agent: Asterisk PBX.

Max-Forwards: 70.

Content-Length: 0.

Note: this message doesn’t appear on the Wireshark datagram.

U 212.147.8.99:64041 -> 91.121.122.64:5081

SIP/2.0 481 Call Leg/Transaction Does Not Exist.

Via: SIP/2.0/UDP 91.121.122.64:5081;branch=z9hG4bK-62ea813d123.

Via: SIP/2.0/UDP 91.121.122.64:5060;branch=z9hG4bK62ea813d;rport.

From: "41215500331" <sip:41215500331@91.121.122.64>;tag=as47fdfeeb.

To: <sip:41215500335@91.121.122.64:5080>;tag=225611292.

Call-ID: 1c6d63870c67e54d28b488e059a696f5@91.121.122.64.

CSeq: 103 BYE.

Supported: replaces, path, timer.

User-Agent: Grandstream GXP1100 1.0.1.83.

Allow: INVITE, ACK, OPTIONS, CANCEL, BYE, SUBSCRIBE, NOTIFY, INFO, REFER, UPDATE, MESSAGE.

Content-Length: 0.

Note: this message doesn’t appear on the Wireshark datagram.

Wireshark file

With this scheme the incoming calls works fine. Now, the messages that send both ASTRAD server and destination phone have the same Call-ID and solve the problem we had with the last scheme.

Note that the BYE message that sends the destination phone is answered with a 481 Call Leg/Transaction Does Not Exist from the ASTRAD server. This means that the call doesn’t finish properly, or in other words, when the destination phone hung up the caller won’t have notice of it and the call will continue active (this behavior is fixed with the new Perl script version).