G7Eleven

Some of our customers use WiFi extension handsets to make phone calls.

Recently, G7Eleven completed a large scale wired and wireless network installation for a College Campus and as part of this project deployment we implented a 3CX VoIP solution that takes full advantage of their new network.

The customer has twenty eight Zone Director managed RUCKUS wireless AP’s throughout their campus property and G7Eleven has limited their VoIP traffic to a special encrypted VLAN. All is working well except one major issue.

Sometimes during a call their WiFi phone roams out of coverage. This is a rare occurrence thanks to the excellent performance of Ruckus Wireless (www.ruckuswireless.com) but it does happen from time to time no matter how good the wireless coverage is.

This is a serious problem as 3CX does not disconnect the handset and the previously live phone call is not cleared by default until the system administrator intervenes and manually closes the call in the 3CX management console.

To make matters worse, when the WiFi phone re-associates to the wireless network it cannot make any further calls until the previous call has been manually cleared. The handset has no knowledge that it was previously on a call and fails to re-register back to 3CX properly and make further calls.

This was very inconvenient for the customer and needed a solution fast.

I therefore had a question?

“Is there a timer in 3CX or setting that I could change to clear the call in this circumstance?”

The answer when it comes to 3CX is of course “YES”

Check the Custom Parameter with name “SIPPINGPERIOD” in 3CX.

Normally this is disabled and when it is enabled it queries the handset so I set the value to 20 seconds. I did not want to set it too short in case the customer lost coverage for a short period of time, for example when they step into a lift during a call and then exit and reconnect to another AP then this call would continue perfectly.

I made a phone call from a WiFi Handset and while on a call placed the phone into a metal box (USA Biscuit Tin actually, aka high tech WiFi signal blocker and very yummy biscuits too..) and after 5-10 seconds the handset lost wireless signal. The call remained open on the 3CX system and after approx 20 seconds was cleared when 3CX SIPPINGPERIOD failed to get an answer from the handset.

Objective achieved. Hope this helps someone else.