Asterisk OUTBOUND SIP REGISTRATIONS timeout


#1

I have install asterisk 1.6.2.20 or 1.6.2.17
I use outbound sip registerations
eg: register=>63362343:63362343@xx.xx.xx.xx
It work ok most time, sometimes I find
[Nov 25 10:54:12] NOTICE[2740]: chan_sip.c:11680 sip_reg_timeout: – Registration for '63362343@xx.xx.xx.xx’ timed out, trying again (Attempt #6).
But I ping xx.xx.xx.xx is right.then I use x-lite registe 63362343 to xx.xx.xx.xx is right.
when I restart asterisk ,it be right again.
why?
I often find this problem in server astersik .

debug:

[Nov 25 11:00:12] NOTICE[2740]: chan_sip.c:11680 sip_reg_timeout: – Registration for '63362343@xx.xx.xx.xx’ timed out, trying again (Attempt #24)
REGISTER 10 headers, 0 lines
Reliably Transmitting (no NAT) to xx.xx.xx.xx:5060:
REGISTER sip:xx.xx.xx.xx SIP/2.0
Via: SIP/2.0/UDP 192.168.0.11:5060;branch=z9hG4bK32a59fec;rport
Max-Forwards: 70
From: sip:63362343@xx.xx.xx.xx;tag=as1fe3e655
To: sip:63362343@xx.xx.xx.xx
Call-ID: 0d7ea5e73e0768487e4699c468e7be95@127.0.0.1
CSeq: 126 REGISTER
User-Agent: Asterisk PBX 1.6.2.17.1
Expires: 120
Contact: sip:s@192.168.0.11
Content-Length: 0


Really destroying SIP dialog ‘0d7ea5e73e0768487e4699c468e7be95@127.0.0.1’ Method: REGISTER

<— SIP read from UDP:220.249.187.114:5063 —>

<------------->
Retransmitting #1 (no NAT) to xx.xx.xx.xx:5060:
REGISTER sip:xx.xx.xx.xx SIP/2.0
Via: SIP/2.0/UDP 192.168.0.11:5060;branch=z9hG4bK32a59fec;rport
Max-Forwards: 70
From: sip:63362343@xx.xx.xx.xx;tag=as1fe3e655
To: sip:63362343@xx.xx.xx.xx
Call-ID: 0d7ea5e73e0768487e4699c468e7be95@127.0.0.1
CSeq: 126 REGISTER
User-Agent: Asterisk PBX 1.6.2.17.1
Expires: 120
Contact: sip:s@192.168.0.11
Content-Length: 0


Retransmitting #2 (no NAT) to xx.xx.xx.xx:5060:
REGISTER sip:xx.xx.xx.xx SIP/2.0
Via: SIP/2.0/UDP 192.168.0.11:5060;branch=z9hG4bK32a59fec;rport
Max-Forwards: 70
From: sip:63362343@xx.xx.xx.xx;tag=as1fe3e655
To: sip:63362343@xx.xx.xx.xx
Call-ID: 0d7ea5e73e0768487e4699c468e7be95@127.0.0.1
CSeq: 126 REGISTER
User-Agent: Asterisk PBX 1.6.2.17.1
Expires: 120
Contact: sip:s@192.168.0.11
Content-Length: 0


Really destroying SIP dialog ‘MmI3NTAzMDcwN2UxYTNkOGU2OWIwZTcwZDdmMTg3NDg.’ Method: REGISTER
Retransmitting #3 (no NAT) to xx.xx.xx.xx:5060:
REGISTER sip:xx.xx.xx.xx SIP/2.0
Via: SIP/2.0/UDP 192.168.0.11:5060;branch=z9hG4bK32a59fec;rport
Max-Forwards: 70
From: sip:63362343@xx.xx.xx.xx;tag=as1fe3e655
To: sip:63362343@xx.xx.xx.xx
Call-ID: 0d7ea5e73e0768487e4699c468e7be95@127.0.0.1
CSeq: 126 REGISTER
User-Agent: Asterisk PBX 1.6.2.17.1
Expires: 120
Contact: sip:s@192.168.0.11
Content-Length: 0


Retransmitting #4 (no NAT) to xx.xx.xx.xx:5060:
REGISTER sip:xx.xx.xx.xx SIP/2.0
Via: SIP/2.0/UDP 192.168.0.11:5060;branch=z9hG4bK32a59fec;rport
Max-Forwards: 70
From: sip:63362343@xx.xx.xx.xx;tag=as1fe3e655
To: sip:63362343@xx.xx.xx.xx
Call-ID: 0d7ea5e73e0768487e4699c468e7be95@127.0.0.1
CSeq: 126 REGISTER
User-Agent: Asterisk PBX 1.6.2.17.1
Expires: 120
Contact: sip:s@192.168.0.11
Content-Length: 0