PnP discovery issues...

[narrington]

this seems to be a pretty dang common issue but I'm not seeing a consistent solution.

I have a batch of new phones I need to provision. they're all Grandstream gxp2170 and I'm on v16.0.4.493. My network is vlanned up but the phone hardware is in vlan 22 (192.168.22.0). I have been able to connect phones using PnP in the past, plug the phone in, wait for it to boot and get an IP, once it has, the phone appears in the phones list in the admin console labled "new". and I can provision from there.

however, I have had issues where periodically I bring in a new phone and it wont show up as new! right now, I have the large batch of phones. I don't have time to go through and manually provision each and every one. So I ran a wireshark from the server to see if the provisioning request is atleast being seen and I see this:

 2334 218.906538440 192.168.22.56 → 224.0.1.75   SIP 726 Request: SUBSCRIBE sip:MAC%[MACADDRESSOFPHONE]@224.0.1.75 |

I'll admit I'm a little uncertain as to what this is saying specifically, but to me it LOOKS like the phone is attempting to subscribe to 224.0.1.75... that is not an IP in my network, nor is it one of our public IPs...

I did try the PnP debugging guide but it didn't really shed any light on the issue, just brought me to wireshark. though the network interface is set to "all-systems.mcast.net" where the guide stipulates it should be "sip.mcast.net" but this is running on 3cx's own debian install, and it has worked before!

So what's the secret sauce? what do I need to do to get auto-provisioning to work?

 

[narrington]

Added note, this has been an ongoing issue for me. I originaly thought it was SBC specific as the last time I tried to provision a phone was over an SBC, however these phones are locally connected.

 

[narrington]

Another update, I manually provisioned one of these new phones and noticed the firmware reported by 3cx doesn't match the phones internal firmware. 3cx says the phone is on 1.0.9.108, but the phone is actully on 1.0.11.3.
I downloaded and updated the firmware just now from this link.

 

[Alphabetic]

That 224 is a multicast address. 3CX will be listening on this range for your phones to shout on for PnP.

If you put your phones on the 3CX supported firmware and do a factory reset what happens?

Is your switch doing anything with multicast? check the settings of your switch.

Assuming 3CX is also in VLAN22

 

[eddv123]

it LOOKS like the phone is attempting to subscribe to 224.0.1.75... that is not an IP in my network

https://www.3cx.com/docs/plug-and-play-ip-phone/

 

[narrington]

That 224 is a multicast address. 3CX will be listening on this range for your phones to shout on for PnP.

I thought as much, but wasn't sure. I'm not as well versed in IGMP as I probably should be.

If you put your phones on the 3CX supported firmware and do a factory reset what happens?

same, kind of.
So last night, I tried to manually provision one of the phones to see how 3cx handled that, just to be sure this is a multicast issue and NOT a issue with the phone itself. manual provisioning worked fine. but in this state, 3cx sees the phone but cant manage it. I told 3cx to update the firmware, and the phone just sat there for an hour. I can make calls from the phone, but when I go into the 3cx client panel and update blfs the phone doesn't change. so the phone is connected to the pbx, but the pbx cant actually control/manage the phone.

So I downloaded the latest supported firmware from here and updated the phone using the maintenance/upgrade tab in the phone's admin page. the phone now reports v1.0.11.3 but when I checked 3cx it was still showing the older firmware still... now this has changed as of right now. 3cx is now showing the correct firmware, but I still can't manage the phone.

Per your recommendation, I've factory reset the phone but is it not appearing in the phone list in 3cx...

You haven't recommended it, but I went ahead and deleted the phone from the extension as well and rebooted the phone. same thing. does not appear in the phone list.

Is your switch doing anything with multicast? check the settings of your switch.

No. I configured the switch myself, and as stated, I'm not as versed in multicast as I should be so I left those settings alone. its a Ubiquiti EdgeSwitch48, if you want, I am willing to post my config file.

Assuming 3CX is also in VLAN22

Correct, all things voip are on vlan22. That said, the pbx IS on another switch... I have two in the rack, the pbx is plugged into the bottom one, the phone is on the top... come to think of it, I believe I provisioned all the previous phones from the bottom switch... I think I'm going to move the phone just to check this. if it works, I'll update here and move my inqueries to a ubiquiti forum.

edit: Nope. same thing. after a factory reset on known compatable firmware connected to the same switch, the phone still does not appear in the phone list in 3cx.

the only other thing I haven't messed with is the network on the switch. after installation, I configured a network bond (round robin) on the server. it has 2 network ports, and we wanted some additionaly redundancy so I just did this in the network config file:
/etc/network/interfaces

auto bond0
iface bond0 inet static
        address 192.168.22.10
        netmask 255.255.255.0
        network 192.168.22.0
        gateway 192.168.22.1
#       dns-nameservers 8.8.8.8 8.8.4.4
        slaves eno1 enp2s0
        bond-mode balance-rr
        bond-miimon 100
        bond-downdelay 200
        bond-undelay 200

I *believe* I did this before the last phone I successfully auto-provisioned... but I might be wrong. it's a work day and we need the phone system live so I cant nuke the bond right now.

 

[narrington]

UPDATE: blew away the bond and updated debian. no change. new phones are still not being detected.

update#2: I just tried a factory reset of one of the phones and now it's working... not sure if it was the bond, or the OS update on the PBX that did it, but I'm working now...

again, this is a pretty common issue. I have seen hundreds of threads on this particular issue... can we get a feature request for an IGMP/multicast/network testing option? NEC, Avaya, and Cisco all have something that you can install on a laptop/PC to test a network for voip performance and reliability. In the case of NEC (which I have used) their utility connects to the PBX and tests a number of functions simpuating a sip/dtx terminal connection to test network performance/stability as well as SIP autoconfiguration (which in our case was basically a test of the tftp server, config file download, provision, and call/audio test... can we get something like this for 3cx?