Hi Sampat,

1. I guess there is no problem with SBG node as timer  value on SBG is
configured in way that it retransmit message
    11 times . That's why SBG sending INVITE 11 times to Destination before
Timer B fires and then after timeout it
     starts posting error response 504  (11 times again) to Source as ACK
not coming .

2. SBG not forwarding CANCEL to Destination as SBG never got even 100
trying from Destination so CANCEL cannot
     be sent out from SBG .

3. Yes there is scope of improvement on SBG side ,it can stop
retransmitting INVITE to Destination after getting Cancel from Source and
should send 487 response to Source .

*Problem here seems to be with Source* : As its expected from Source to
gracefully send ACK for every final response .



Thanks & Regards
Ankur Bansal


On Fri, Sep 20, 2013 at 11:08 AM, sampat patnaik <sam_e...@yahoo.co.in>wrote:

> Hi,
>
> Greetings of the day!!!
>
>
> Can anyone help me on this ongoing issue.
>
> Regards
> Sampat
>
>
> ----- Forwarded Message -----
> From: sampat patnaik <sam_e...@yahoo.co.in>
> To: Rupesh Mothe <rm0063...@techmahindra.com>; "
> sip-implementors@lists.cs.columbia.edu" <
> sip-implementors@lists.cs.columbia.edu>
> Sent: Thursday, 19 September 2013 11:50 PM
> Subject: Re: [Sip-implementors] SIP ISSUE
>
>
>
> Hi Rupesh,
>
> 1)Incase that case what is expected out of source node..i.e the SBG(proxy)
> must be expecting an ACK message to the error 504 sent..right?
> 2) second query would be why not this CANCEL message is forwarded to next
> hop i.e destination node .should the flow mentioned below be followed:
>
> SOURCE          SBG(Proxy 1)          DESTINATION
>      |                |                |
>      |   INVITE F1
>  |                |
>      |--------------->|    INVITE F2    |
>      |     100  F3    |--------------->|
>      |<---------------|    INVITE F4
>      |                |--------------> |
>                            INVITE F5
>      |                |--------------> |
>      |
>  |    INVITE F6  |
>      |                 --------------->|
>                            INVITE F7
>                        --------------->
>                            INVITE F8
>                        --------------->
>      |
>  |                |
>      |   CANCEL F9    |                |
>      |--------------->|                |
>      |     200 F10    |                |
>      |<---------------|   CANCEL F11   |
>      |                |--------------->|
>      |                |     200
>  F12    |
>      |                |<---------------|
>      |                |                |
>      |                |      487 F17   |
>      |                |<---------------|
>      |                |       ACK F18  |
>
>  |                |--------------->|
>      |                |                |
>      |                |                |
>      |                |                |
>      |                |
>  |
>      |                |                |
>      |     487 F19    |                |
>      |<---------------|                |
>      |     ACK F20    |                |
>      |--------------->|                |
>      |
>  |
>
> 3) i would suspect that the INVITE in F11 message(trailing mail) is becoz
> the cancel request is not being sensed by the SBG and is busy
> in resending the REINVITE message to the destination(maximum 7 invites due
> to timer issue of 64*T1 i.e 32secs) .Also i thing the error
> 504 is populated because there is time out error generated after destn
> server failed to respond to 7th(F11) reinvite request and is
> flooded to sorce side expecting an ACK before ending the entire process.
>
> 4)what would have happened had there not been that F11 invite message?
>
> Thanks in advance.
>
> Regards
> Sampat
>
>
>
>
> ________________________________
>  From: Rupesh Mothe <rm0063...@techmahindra.com>
> To: sampat patnaik <sam_e...@yahoo.co.in>
> Sent: Thursday, 19 September 2013 11:28 PM
> Subject: RE: [Sip-implementors] SIP ISSUE
>
>
> Hi Sampat-
>
> This is expected behaviour , 504 should get retransmitted no issues , you
> need to set the retransmit value in proxy to minimize the flooding
> Issue i am seeing here is the 11th INVITE getting transmitted from proxy ,
> once it sent 200OK for CANCEL it should not send retransmitted INVITE any
> more
>
>
> Thanks & Regards,
> Rupesh Mothe | NPA | Tech Mahindra
> Mobile: +91 9960727012 , +233-263597627
>
>
> -----Original Message-----
> From: sampat patnaik [mailto:sam_e...@yahoo.co.in]
> Sent: 19 September 2013 23:21
> To: sip-implementors@lists.cs.columbia.edu
> Subject: [Sip-implementors] SIP ISSUE
>
> Hi,
>
> I am currently facing an issue that as follows :..my question is why
> PROXY1 is unable to process the CANCEL message  in this case.
>
> CASE:  REMOTE NODE IS COMPLETELY DOWN and we need to understand why
> flooding of 504 sip error is happening  towards source side while it is not
> responding withACK mesg
>
>
> SOURCE            Proxy 1              REMOTE  NODE
>
>  |                |                |
>     |   INVITE F1    |                |
>     |--------------->|    INVITE F2    |
>     |     100  F3    |--------------->|
>     |<---------------|    INVITE F4
>     |                |--------------> |
>                           INVITE F5
>
>  |                |--------------> |
>     |                |    INVITE F6  |
>     |                 --------------->|
>                           INVITE F7
>                       --------------->
>                           INVITE
>  F8
>                       --------------->
>     |                |                |
>     |   CANCEL F9    |                |
>     |--------------->|                |
>     |     200 F10    |                |
>     |<---------------|   INVITE F11   |
>
>  |                |--------------->|
>     |                |                |
>     |                |                |
>     |      504 F19                    |                |
>     |<---------------|                |
>
>  |      504 F20                    |                |
>     |<---------------|                |
>     |     504 F21    |                |
>     |<-------------  |                |
>     |                |                |
>
>  |                |                |
>
>
>
> 504 message is sent 11 times from proxy to source..why this abnormal
> behavior?
>
> Thanks in advance
>
> Regards
> Sampat
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