[asterisk-bugs] [JIRA] (ASTERISK-21677) SIP Notify / BLF Stop Working

[Alec Davis (JIRA)]

    [ https://issues.asterisk.org/jira/browse/ASTERISK-21677?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=205781#comment-205781 ] 

Alec Davis commented on ASTERISK-21677:
---------------------------------------

I had wondered why BLF's would stop randomly, then rebooting the device they would stop again within minutes!
Review1813 deals with buggy Grandstream firmware that accepts a unsolicited (because the device was rebooted) BLF update. The version number of the BLF subscription gets set to the old subscription.

This lost notify issue, is more interesting.

{code}
referring to RFC4235
3.10.  Rate of Notifications

   For reasons of congestion control, it is important that the rate of
   notifications not be excessive.  It is RECOMMENDED that the server
   not generate notifications for a single subscriber faster than once
   every 1 second.
{code}

The 'for a single subscriber', is that rate control for a peer that may have many BLF subscriptions, or for each subscription?

Implementing a timer on each subscription then would allow retries and rate control.

Your suggestion to remove the flag, similar code was removed in Asterisk 1.2, which would remove old subscriptions related to a peer.

Not that this fixes your problem right now.

                
> SIP Notify / BLF Stop Working
> -----------------------------
>
>                 Key: ASTERISK-21677
>                 URL: https://issues.asterisk.org/jira/browse/ASTERISK-21677
>             Project: Asterisk
>          Issue Type: Bug
>      Security Level: None
>          Components: Channels/chan_sip/General
>    Affects Versions: 11.3.0
>         Environment: Centos 5.6, Quad Core Intel Xeon @ 3.0GHZ, 4GB RAM
>            Reporter: Dan Martens
>
> Hello, 
> We have noticed that since we upgraded to Asterisk 11, the BLF lamps on phones (multiple makes and models) stop working from time to time.  To get them to work again, we have to bring the device offline and back online again.
> When this happens, we start to see a lot of "queued" messages in the logs regarding the extension that is not working.  For example:
> Extension Changed 100[witgoffice-local] new state Ringing for Notify User witg_116 (queued)
> Once a device is listed as "queued", it will never be dequeued unless you make it go offline.  It gets stuck in this state.
> SIP network traces show that once the device goes into queued state, Asterisk will no longer send any NOTIFY messages.  It only sends them when it is in non-queued state.  
> A brief look at the code, shows that the flag which gets reset to allow these notifications to get through only gets reset in a single branch of code:
> chan_sip.c at 22939 in handle_response_notify 
> ast_clear_flag(&p->flags[1], SIP_PAGE2_STATECHANGEQUEUE);
> This will only occur when a device sends back a 200 OK request to a previous NOTIFY message.  If this response never comes back (ie. packet loss etc.), then the flag gets stuck in this state forever.
> I would propose that a fix to this would be to reset the flag:
> ast_clear_flag(&p->flags[1], SIP_PAGE2_STATECHANGEQUEUE);
> during either a SUBSCRIBE request or REGISTER request.  That way, if the flag is stuck, it will get reset in a short amount of time when the device performs its next registration routine.  That is, unless I am completely wrong or there is a better way of doing things.
> Your help is greatly appreciated.
> Thanks,

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