CANCEL or BYE

[jaiume]

How does 3CX decide if it should send a SIP CANCEL or BYE?

I am using 3CX with a Grandstream Budgetone 101 hardphone and a Grandstream GXW-4008 FXS gateway.

When calling the Budgetone 101, if the caller hangs up before it is answered, 3CX sends a CANCEL. However in the same scenario with the GXW-4008 it seems to send a BYE.

Both devices send that they support both BYE and CANCEL when they register. And they are registered exactly the same way as extensions.

Jamie

 

[jaiume]

There seems to be a problem with 3CX, for some reason it sends the GXW-4008 a SIP BYE instead of a CANCEL.

I have been through it with Grandstream tech support, and have tried to replicate the behaviour with another IP PBX (Axon), and it only happens with 3CX. Axon seems to send the CANCEL, and the GXW-4008 stops ringing immediatly.

3CX only seems to send the BYE rather than a CANCEL where the GXW-4008 is concerned, it sends a CANCEL to every other SIP client I have.

Jamie

 

[jaiume]

Could someone from 3CX shed some light on this issue. Its very strange that 3CX modifies its behaviour just for the GXW-4008.

Grandstream had a look in detail at the network traffic between 3CX and the GXW-4008, and they told me that for some reason 3CX is not sending a CANCEL message, its only sending a BYE.

Grandstream have told me they will be changing their firmware to terminate a call on BYE without CANCEL, but they said that its not really correct w.r.t. the protocol.

 

[N_G]

We will look into this and let you know.

 

[archie]

How does 3CX decide if it should send a SIP CANCEL or BYE?

We're behave in full compliance to RFC 3261. If dialog has been established (we got 18x response with 'Contact' header) than it would be terminated with BYE. Otherwise, we send CANCEL.

 

[schnobbr]

Same issue

I believe I am having the same issue. If I call a sip phone through my GXW4104 and answer the phone, and then hang up the sip phone, the line between the GXW4104 and 3CX becomes available immediately.

If I call a sip phone through my GXW4104 and hit cancel on the phone I am calling from, the line stays busy for about 20 minutes before it finally disconnects.

I am using 3CX Phone System v3.0.1928.0
GXW4104 1.0.0.41

Jaiume, Did the new firmware fix your issue?

 

[archie]

No, this means exactly that your GXW4104 doesn't notice that line is hanged up. Try to adjust line settings in gateway options (if it has ones). You should be able to select more suitable hangup detection mechanism, line voltage and such parameters.