Extension with multiple phones

[ajcke]

One of my teachers has a phone in her office an the other in her classroom. Intermittently only one phone will ring. Sometimes the office phone will ring and visa versa, and other times both phones will ring like they are supposed to.

Things I've checked.

• Occurs whether on an inbound call in our network or from outside the network.
• The time of the day doesn't seem to matter.

Environment

• 3cx 15.5
• Server OS WS 2012 R2
• Yealink T42S Phones, 66.83.0.55 firmware

 

[leejor]

Are these sets a part of a ring group, the same extension number, remote to the 3CX server, or on the same LAN. If remote, how are they connected, STUN?

 

[ajcke]

I do not have a ring group setup for these. Same extension number for both phones. Same LAN, same switch.

 

[leejor]

Then I would check the 3CX Activity Log after a call where one set does not ring. Do both sets appear to be registered, was an Invite not sent to one, for that reason (not registered), or some other?

 

[cobaltit]

Sorry mixed up my threads.

Does same LAN mean same subnet, no NAT in-between?

 

[ajcke]

Here's some more information. When looking at the network switches I do have some inconsistencies. I'm using Cisco equipment. What is recommended? Is any of the following configurations unnecessary?

Voice ports on the older equipment are configured like this:
interface FastEthernet0/36
description *** Voice Port ***
switchport access vlan 10
switchport trunk native vlan 10
switchport mode trunk
switchport voice vlan 20
srr-queue bandwidth share 1 30 35 5
priority-queue out
mls qos trust device cisco-phone
mls qos trust cos
auto qos voip cisco-phone
spanning-tree portfast
spanning-tree bpduguard disable
service-policy input AUTOQOS-SRND4-CISCOPHONE-POLICY
!

Voice ports on newer equipment are configured like this:
interface GigabitEthernet1/0/3
description *** Voice Port ***
switchport access vlan 10
switchport mode access
switchport voice vlan 20
spanning-tree portfast
spanning-tree bpduguard disable
!

The teacher also has a third phone in a shop environment with the same extension. Before I switched to Yealink phones this never happened. The unsupported Cisco phones rang every time.

I was doing some work out there today and finally had the opportunity to witness the intermittent ringing the teacher has been telling me about. It was an internal call (extension to extension). They called twice because the phone didn't ring in her classroom so she didn't pickup. The second call I picked up in the office. I checked the history on each phone.

• Office Phone
  • 10:26AM Ring, displays in phone history
  • 10:27AM Ring, displays in phone history
• Classroom Phone
  • 10:26AM No Ring, Doesn't display in phone history
  • 10:27AM No Ring, Doesn't display in phone history
• Shop Phone
  • 10:26AM Displays in phone history
    
  • 10:27AM Doesn't display in phone history
    
  • No one was out there to hear the phone ring
• The server call log
  • 10:26AM Not answered then the next line, extension's voicemail
  • 10:27AM Extension picked up

Is it best practice to assign a different extension to each phone and put the phones in a ring group or is it best practice to assign each phone the same extension? What is recommended?

 

[leejor]

Did you ever look at the Activity Log to see what extensions the PBX actually attempts to send Invites to? If it isn't attempting to send to all, why not?
SIP forking (same extension on multiple sets) is supported, and should work.

To quickly eliminate network issues, Take all 3 sets, moving two of them to where a third one is located. Plug them all into a small switch at the one location. Make some test calls to the extension number. you can then see the behaviour of all 3 sets. Check the Activity Logs.

 

[ajcke]

Whenever I try to ring all three sets they all ring. It's intermittent, but it is happening daily.

Here's what the log says.

12/12/2018 10:26:47:192 | 8 | Call to T:Extn:1604@[Dev:sip:[email protected]:5060,Dev:sip:[email protected]:5060,Dev:sip:[email protected]:5060] from L:660.1[Extn:1206] failed, cause: Cause: 486 Busy Here/INVITE from 10.55.4.107:5060

12/12/2018 10:27:23:649 | 8 | Call to T:Extn:1604@[Dev:sip:[email protected]:5060,Dev:sip:[email protected]:5060,Dev:sip:[email protected]:5060] from L:661.1[Extn:1206] failed, cause: Cause: 486 Busy Here/INVITE from 10.55.4.107:5060

 

[leejor]

Is it always the same set causing the Busy Here? Remove (unplug) that set, see if the issue continues with just the other two, then look into why that set is reporting that it is busy. Setting? Any other line appearance on that set? Compare to the other sets. Perhaps a factory reset, and a re-provision are in order. Is Firmware up-to-date?

 

[ajcke]

It is not always the same set that doesn't ring. It seems random. Today I factory reset and reprovisioned all three phones. I successfully placed test calls from phone webpages of extensions that are known to not consistently ring all three phones. All three phones rang with each test. The user has been instructed to inform me if the issues happens again.