[SIPForum-discussion] ACK was not receiced by B

[Ferris Salvador]

Hi
Any device before B can drop an ACK packet (like P proxy), so as all people said previously, the uas B will resend 200-OK at 0,5s (T1), 1s, 2s, 4s, 4s ... until 32 seconds (T64). It is assumed there is no problem about losing a packet, simply solve the bottleneck.
If the loss of the ACK packet occurs always, perhaps it's a misconfiguration issue at B side and becouse of that I recomend you to check the "contact" header at the 200-OK/INV packet. 
The uac A sends ACK paquet to the IP address value in the "Contact" header of the 200/OK sent by B. 
If the B IP address is the same in the Contact header mentioned as in the first INVITE message, there is no reason to think of a routing problem. Otherwise, it could be a routing or firewall isue.

Regards,

-----------------------------
Salvador FERRIS FERRAGUD
Ingenieria de red
PROSODIE IBERICA 
Grupo Capgemini
Tel.: + 34 902 636 333
e-mail: sferris at prosodie.es
-----------------------------



-----Mensaje original-----
De: Subhasish Panda [mailto:pandasubhasish at gmail.com]
Enviado el: vie 12/12/2014 6:19
Para: Ferris Salvador
CC: discussion at sipforum.org
Asunto: Re: [SIPForum-discussion] ACK was not receiced by B
 
Hi,

Ferris: what are chances that packet will not reach from P to B .Suppose a
network fluctuation or due to any disturbance.  ACK is not reached from P
to B



On Thu, Dec 11, 2014 at 9:34 PM, Ferris Salvador <sferris at prosodie.es>
wrote:
>
>
> Hi Subhasish
> Check step (5) and have a look to the contact header in the 200-OK.
> Perhaps it contains  a wrong IP address for the uas B.
> Regards,
>
> -----------------------------
> Salvador FERRIS FERRAGUD
> Ingenieria de red
> PROSODIE IBERICA
> Grupo Capgemini
> Tel.: + 34 902 636 333
> e-mail: sferris at prosodie.es
> -----------------------------
>
>
>
> -----Mensaje original-----
> De: discussion-bounces at sipforum.org en nombre de Subhasish Panda
> Enviado el: mar 09/12/2014 9:44
> Para: discussion at sipforum.org
> Asunto: [SIPForum-discussion] ACK was not receiced by B
>
>
> Please let me know the answer
>
> There are two user-agents (A and B) , one proxy server (P)
>
>
> 1) A sends INVITE        to P
> 2) P forwards INVITE      to B
> 3) B sends  180    to P
> 4) P sends  180    to A
> 5) B sends  200    to P
> 6) P sends  200    to A
> 7) A sends  ACK    to P
> 8) P sends  ACK    to A (when P sends ACK packet to B the packet is lost so
> how the call is going to take place or the transaction or what will happend
> to the session  ?)
>
> --
> Thanks
> Subhasish panda
>
>

-- 
Thanks
Subhasish panda

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