26 lines
1.2 KiB
Plaintext
26 lines
1.2 KiB
Plaintext
Glare is a PITA.
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Although configuration of ISDN links can be done to minimize glare, we also must have a clear policy
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on how the FreeTDM API is supposed to behave on glare across signaling modules.
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There is a well-known race in the FreeTDM API since the beginning. When a user wants to place a call with
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the old APIs:
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1. ftdm_channel_open_xx (to hunt the channel by group, span or select a channel individually)
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2. ftdm_channel_call_place() to place the actual call.
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Since the user has no access to channel locking, between opening a channel and placing a call, an incoming call could be
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received. Therefore things can get complicated and that is why you should STOP USING those 2 deprecated functions.
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The replacement is ftdm_call_place().
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ftdm_call_place receives the information required to hunt the channel and place the call.
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If glare is detected after placing the call and the signaling stack decides to drop the local call, a regular
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SIGEVENT_STOP will be sent with the hangup cause FTDM_CAUSE_REQUESTED_CHAN_UNAVAIL.
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ftdm_call_place may return FTDM_BREAK if glare is detected while placing the call, in such cases you can try
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calling ftdm_call_place again to hunt another channel.
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