[SIPForum-discussion] 481 Transction Does not Exist & ACK for 200 OK

[Raghul Prasanna]

Thanks Fatine, but is there anyway we can expect a response for an ACK in this scenario from the far end device?
>From my first post
>>Is it true that 481 message will be returned only for SIP message, that requires a response and in this scenario ACK doesnt trigger any response, so we shouldnt be expecting any message from SBC that it doesnt understand the transaction?
Raghul

--- On Tue, 29/3/11, Fatine Taoufik <T.Fatine at iam.ma> wrote:

From: Fatine Taoufik <T.Fatine at iam.ma>
Subject: RE: [SIPForum-discussion] 481 Transction Does not Exist & ACK for 200 OK
To: "Raghul Prasanna" <raghul82 at yahoo.co.uk>, discussion at sipforum.org
Date: Tuesday, 29 March, 2011, 16:57



 



 
 

Hi 
Raghul,
 
The 
SBC should protoct the SIP platform. If it received ACK messages after the timer 
defined in the SBC, It shoult reject them automaticaly without 
crashing.
 
I think also if the sbc forward these messages 
(ACK) to the proxy, It will reject them also. So, the problem I thing is to look why ACK messages 
take long time to arrive to the SBC.
 
I don't know if just Ack messages that arrive late or 
SIP responses also.
 
Good luck
 



T.Fatine



De : discussion-bounces at sipforum.org 
[mailto:discussion-bounces at sipforum.org] De la part de Raghul 
Prasanna
Envoyé : lundi 28 mars 2011 09:52
À : 
discussion at sipforum.org
Objet : [SIPForum-discussion] 481 
Transction Does not Exist & ACK for 200 OK




  
  
    
      Hello All,
       
      I have the following scenario.
       
      Application Server Sends ACK to 200 OK from an SBC.  But due to 
      network delay, the ACK took several mins to reach the SBC and the SBC in 
      the meantime crashed and rebooted, so lost its session.
       
      When it received the ACK for the 200 OK it sent before the crash, it 
      didnt relate to any of its session as it had crashed and recovered a 
      min ago.
       
      I expected the SBC to return 481 Transaction\Dialog does not exists 
      or some of form of indication to the App Server, stating it doesnt 
      understand, but nothing came back. So as far as the App server was 
      concerned, the call got established.
       
      What can be done in this situation? Is it true that 481 message will 
      be returned only for SIP message, that requires a response and in this 
      scenario ACK doesnt trigger any response, so we shouldnt be expecting any 
      message from SBC that it doesnt understand the transaction? 
       
      If someone thinks that its wrong and SBC should have responded with a 
      message clearly saying I dont understand what you are saying to me, then 
      please lemme know and if any rfc points to this, let me know that as well 
      please?
       
      Any input will be really helpful.
       
      Thanks,
      Raghul
 



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