Andrea,
ACK requests shouldn't be responded even if its malformed. Either it should be
processed or silently ignored.
Further, clients are also not supposed to handle responses to ACK.
Though it is not explicitly mentioned, here are some excerpts which is implicit
to say that ACK shouldn't be responded.
>> The client transaction is also responsible for receiving responses
and delivering them to the TU, filtering out any response
retransmissions or disallowed responses (such as a response to ACK).
>> While a server can legitimately challenge most SIP requests, there
are two requests defined by this document that require special
handling for authentication: ACK and CANCEL.
Under an authentication scheme that uses responses to carry values
used to compute nonces (such as Digest), some problems come up for
any requests that take no response, including ACK.
Regards,
Manjunath
-----Original Message-----
From: sip-implementors-boun...@lists.cs.columbia.edu
[mailto:sip-implementors-boun...@lists.cs.columbia.edu] On Behalf Of Andrea
Sent: Friday, 3 April, 2015 5:11 PM
To: sip-implementors
Subject: Re: [Sip-implementors] replies to ACK
Thanks for your fast answers!
Is there any RFC statements regarding the fact that UAS should ignore the
malformed ACK?
I have to persuade the UAS implementor!
Thanks
Andrea
2015-04-03 11:04 GMT+02:00 Alok Tiwari <alo...@globallogic.com>:
> Hi Andrea,
> UAS should simply ignore the malformed ACK messages. Since the ACK
> message is malformed, UAS will re-transmit the 400 response of INVITE
> for 32 seconds.
>
> Thanks,
> Alok Tiwari
>
> On Fri, Apr 3, 2015 at 2:29 PM, Andrea <fuffa...@gmail.com> wrote:
>
>> Hi,
>> we are facing an issue where a malformed INVITE generate a message
>> storm (loop).
>> UAC send a malformed INVITE to UAS (from and contact header invalid)
>> UAS replies with error 400 bad request UAC send a malformed ACK to
>> UAS (from and contact header invalid) UAS replies with error 400 bad
>> request in response to the malformed ACK UAC send a malformed ACK to
>> UAS in response to the latest 400 bad req and the loop continues....
>>
>> this generate a message storm that is consuming cpu resources for 32
>> seconds.
>>
>>
>> I looked for specific RFCs but I cannot find something clear.
>> So, the question: is it admitted that the UAS replies to the ACK with
>> a
>> 400
>> bad request or it should simply ignore the malformed ACK?
>>
>>
>> Thanks in advance
>>
>>
>> Andrea
>> _______________________________________________
>> Sip-implementors mailing list
>> Sip-implementors@lists.cs.columbia.edu
>> https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
>>
>
>
>
> --
> Alok Tiwari | Consultant
> GlobalLogic
> P +91.120.406.2000 x 2477 M +91.991.034.7139 S alo...@globallogic.com
> <http://alok.t_globallogic.com/> www.globallogic.com
> <http://www.globallogic.com/>
> http://www.globallogic.com/email_disclaimer.txt
>
_______________________________________________
Sip-implementors mailing list
Sip-implementors@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
_______________________________________________
Sip-implementors mailing list
Sip-implementors@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
