@Jens. thanks
If we can read/write packets to detect closed socket, why is there TCP keep
alive ??
On Tue, May 7, 2013 at 2:07 PM, Jens Jorgensen <jbj1 at ultraemail.net> wrote:
> Well the thing is just because you sniffed the packet off the wire
> doesn't in any way mean the "client" (i.e. the SIP software) has actually
> received it. In fact, a pretty reasonable piece of SIP code (I'll just
> write Python pseudo-code for brevity) might look something like:
>
> s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
> s.connect( (server, port) )
> s.send('REGISTER ....')
> while True :
> bytes = s.recv(256)
> if len(bytes) == 0 :
> # uh-oh, the remote end closed the socket
>
> And in fact even if the OS has received the [FIN,ACK] already when
> s.send() is called, this will *not* cause an error. The send() will
> complete successfully. Try it!
>
>
> On 5/7/13 2:58 PM, Khoa Pham wrote:
>
> @Jens, thanks for reply
>
> But client already received the [FIN,ACK] from server, it should know
> that sending REGISTER does not make sense anymore
>
>
> On Tue, May 7, 2013 at 12:13 PM, Jens Jorgensen <jbj1 at ultraemail.net>wrote:
>
>> You make it sound like you want the client to hang up?! As you know, the
>> primary way a program finds out if a socket is closed is to try reading or
>> writing on it. In this case the server has closed its end of the socket but
>> the client probably doesn't know that (yet)--evidently because it thought
>> it would get the chance to REGISTER
>>
>> On 5/6/13 5:15 PM, Khoa Pham wrote:
>>
>> Hi pjsip team,
>>
>> When I make REGISTER request to server, I often receive this
>>
>> 1. client: SYN
>> 2. server: SYN, ACK
>> 3. client: ACK
>> 4. server: FIN, ACK
>> 5. client: REGISTER
>> 6. server: RST
>>
>> Why in step 5 does client not send FIN, ACK ??
>>
>> --
>> Khoa Pham
>> HCMC University of Science
>> Faculty of Information Technology
>>
>>
>> _______________________________________________
>> Visit our blog: http://blog.pjsip.org
>>
>> pjsip mailing listpjsip at lists.pjsip.orghttp://lists.pjsip.org/mailman/listinfo/pjsip_lists.pjsip.org
>>
>>
>> --
>> Jens B. Jorgensenjbj1 at ultraemail.net
>>
>>
>> _______________________________________________
>> Visit our blog: http://blog.pjsip.org
>>
>> pjsip mailing list
>> pjsip at lists.pjsip.org
>> http://lists.pjsip.org/mailman/listinfo/pjsip_lists.pjsip.org
>>
>>
>
>
> --
> Khoa Pham
> HCMC University of Science
> Faculty of Information Technology
>
>
> _______________________________________________
> Visit our blog: http://blog.pjsip.org
>
> pjsip mailing listpjsip at lists.pjsip.orghttp://lists.pjsip.org/mailman/listinfo/pjsip_lists.pjsip.org
>
>
> --
> Jens B. Jorgensenjbj1 at ultraemail.net
>
>
> _______________________________________________
> Visit our blog: http://blog.pjsip.org
>
> pjsip mailing list
> pjsip at lists.pjsip.org
> http://lists.pjsip.org/mailman/listinfo/pjsip_lists.pjsip.org
>
>
--
Khoa Pham
HCMC University of Science
Faculty of Information Technology
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