[OpenSIPS-Users] opensips1.6.1 and Polycom BLA

[Steven C. Blair]

Thanks,

 What we see is:

When a Polycom handset's registration expires, the REGISTER is sent to SER, which also sends it to OpenSER.

OpenSER then sends a SUBSCRIBE back to the handset through SER.

The handset sends back its presence state using state="full" in the dialog-info.

OpenSER takes this state and applies it to every handset in the BLA group.

The problem is:

Let's say there's an ongoing call in a BLA group that is put on hold.
Then, there's a second call that comes into the BLA group and is picked up by a handset.
If this handset happens to re-register at this time, the REGISTER ends up in the handset sending a full state update to OpenSER following the specs above.

This full state update does not contain the information about the first call, so the first call's state is removed from each handset as well as OpenSER.  The handset still think there's a held call but the light turns off and it can no longer be picked up.

Questions / Comments:

Why doesn't the re-registering handset include the status of the first call in its state update to OpenSER when it receives a SUBSCRIBE?  
Should OpenSER ignore the NOTIFY message from re-registering handsets, or should it send its own state to the handset before the SUBSCRIBE?

Or, should the handset be using state="partial" since it's only sending state about the second call?  If so, how can OpenSER ask for a partial update in SUBSCRIBE?

-Steve

-----Original Message-----
From: users-bounces at lists.opensips.org [mailto:users-bounces at lists.opensips.org] On Behalf Of Anca Vamanu
Sent: Tuesday, February 09, 2010 12:23 PM
To: OpenSIPS users mailling list
Subject: Re: [OpenSIPS-Users] opensips1.6.1 and Polycom BLA

Hi Steven,

Thank you for the in dept analysis of the problem. I have now checked 
the implementation for BLA in opensips and here is the state of OpenSIPS 
BLA from in what those two sections are concerned.
8.2 - Subscription timeout
OpenSIPS BLA sends Subscription when Register messages are received or 
when a registration timeouts. So the case when a Subscribe message is 
not replied can only happen if in the short period when the phone sent 
the Register and OpenSIPS sent the Subscribe went down - and there is 
really very little change this will happen.
8.3 - Notify race condition
The implementation does not handle this case as mentioned in the draft, 
and this could be a problem( maybe exactly the problem that you are 
seeing). OpenSIPS will overwrite the state with the second call, and 
maybe in the mean time the phone that have sent the first Notify has 
already started the call. I will have to work a bit in this part and 
make the logic more strong.

Thanks and regards,

-- 
Anca Vamanu
www.voice-system.ro


Steven C. Blair wrote:
> Does anyone have any experience with Polycom phones, BLA using OpenSIPS as the state agent? If so I'm wondering if you can talk to a few points in the draft RFC? 
>
> http://tools.ietf.org/html/draft-anil-sipping-bla-02#section-8.2
>
> Section 8.3, line seize race condition, seems to describe our current issue as the user sees it. Section 8.2, Line seize notifier failure, seems to describe what we are seeing in logs. Can anyone talk to how Polycom and OpenSIPS handles these two conditions? Does anyone have any hands-on experience with these types of problems in an operational setting?
>
> Thanks,Steve
>
> -----Original Message-----
> From: users-bounces at lists.opensips.org [mailto:users-bounces at lists.opensips.org] On Behalf Of Steven C. Blair
> Sent: Monday, February 08, 2010 10:19 AM
> To: OpenSIPS users mailling list
> Subject: Re: [OpenSIPS-Users] opensips1.6.1 and Polycom BLA
>
>
> Anca,
>
>  You are too quick.:-) I was about to send an update saying I found the problem. Thanks but please disregard this message
>
> -----Original Message-----
> From: users-bounces at lists.opensips.org [mailto:users-bounces at lists.opensips.org] On Behalf Of Anca Vamanu
> Sent: Monday, February 08, 2010 9:59 AM
> To: OpenSIPS users mailling list
> Subject: Re: [OpenSIPS-Users] opensips1.6.1 and Polycom BLA
>
> Hi Steven,
>
> Could you please investigate more into the problem that you are noticing?
> Do you see any errors in the log? Increase the log level to see the 
> debug messages and check what in the following steps in the processing:
> 1. when register is received and you have called bla_set_flag on it - 
> you should see the pua_bla module sending a Subscribe message to the phone
> 2. when the notify is received from the phone - the pua_bla module 
> should send a Publish with that information
> 3. also check if there is any Subscribe message for event: dialog;sla 
> received from the phone.
>
> Regards,
>
>   

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