[Foip] Call Flows summary [Update III]

[Sebastien BOIRE-LAVIGNE]

[Update III]

This is the last week to make comments and make sure we cover all
practical scenarios. So hurry up!!! Next week we will discussed what
scenarios should we recommend to support and/or not  to support.

 

Regarding the call flows, here few comments:

*         Scenario 3.x: Fax calls usually go first into voice and then
into T.38. Should we require IAF to support T.38 "direct" call flow. Do
we need it and what is the benefit?

*         4.1 and 4.2, for all practical matter are "advanced" scenarios
and should probably be "in a special category"

*         In scenario 4.3, it is possible that T.38 packets are received
and discarded by the UA1, increasing the risk of fax failures. Should we
always recommend 4.2 for that type of scenario?

*         Scenario 5, The re-invite in T.38 role is reverse from what is
done in scenario 1 (THIS IS MAJOR) and is in use, at least for SG3
calls, by one of the largest manufacturer of VoIP Gateways.  So it is
possible that both side try to re-invite in T.38 at the same time since
scenario 1 and 5 "conflicts". If we recommend to recommend support that
scenario, which I believe we have no choice to do, we need to define how
to break the stalemate. I believe Kevin mentioned an existing technique
for that in SIP.

 

 [Update II]: 

-          Added Ok response to first T.38 invite in scenario 4.3
(Comments from Sagem)

-          Change the trigger to the T.38 Invite from CNG to CED/ANSam
detection for scenario 1-2 (Comments from Nortel)

 [Update I]: Section 3.0, the text was not using the latest from
Nilantha, fixed that and added a reference section.

 

***

Hi all,

 

Here a document that summarizes the call flows posted on the mailing
list (Acculab, Dialogic and Sagem), if I missed anything let me know.

 

I also created a survey to see what scenarios each of us are
using/supporting. It's a 10 questions survey, asking if you support each
of the 9 scenarios described in the document. The 1 first question ask
you to identify your product/company, but this is optional if you want
to answer anonymously. If you have multiple products with different FoIP
support, you can respond to the survey multiple times.

 

Once you looked at the document you can take the survey at 
http://www.surveymonkey.com/s/FMYK2FV . At the end of the survey you
will be sent to a page showing the results. The results can also be
consulted at anytime by anybody at 
http://www.surveymonkey.com/sr.aspx?sm=xIYi_2bksE7_2bW1JPmNDeNPcOpPF_2bf
pZFmdOR3rTnmK_2b9Y_3d 

 

I hope the survey will help us understand how widespread the support for
"non-standard" scenarios is.

 

Cheers,

SBL

 

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