Solved How to: Phones in multiple locations

[jfester]

Hello,

I come from an Avaya background and trying to determine if I should keep my new employer with 3CX or move them to another provider. We are a school and just purchased a new building a mile away that will become a 2nd campus for us, same school. We will need to have phones at both locations. We are currently hosted on-premises on Linux standard license of 3CX. They are POE connected phones. The question is: does 3CX have the capability of supporting phones at any location? I know I will need to get poe injectors for the phones, but we need phones at the new location and users from home.

I want to migrate the hosting to the cloud, whether AWS, Azure or another host. I read that 3CX has this SBC that must be running for your 3CX phones to connect. But this implies to me that every location would need to have an SBC running? Seems strange to me.

In my experience, IP phones just need to be plugged in to any internet (with poe injectors or on a poe switch) and they will auto-discover the host and connect and you're done. Avaya makes this pretty easy to do.

Thank you for your help & advice!

 

[sbrammer]

We are also a school and have a few different locations in our district. We have 3cx running on a Windows box, and phones are configured to use Local LAN as the config method in all locations. However, for a test during our Stay at Home, I configured a phone for Direct-SIP (STUN remote, took it home, plugged into my home router, plugged into power, and was able to receive\make calls using my work extension from my home.

 

[jfester]

We are also a school and have a few different locations in our district. We have 3cx running on a Windows box, and phones are configured to use Local LAN as the config method in all locations. However, for a test during our Stay at Home, I configured a phone for Direct-SIP (STUN remote, took it home, plugged into my home router, plugged into power, and was able to receive\make calls using my work extension from my home.

Thank you for the info! So the only remaining piece to know is about hosted solution, where if I understand 3CX documentation, the SBC is still required to be running on-premises (which premises I wonder...) for this to work, but all other premises where the SBC is not located will continue to work? Still confusing a bit. But also, one reason I wanted to go to a hosted solution is to avoid any outages if we lose power (lots of lightning strikes outages here) or the internet goes down, etc. Being on-premises hosted means if either of these happens we lose phones. So I wanted to host it in the cloud so that phones always work from other locations even if we go down...but with the requirement of having an SBC running...this seems pointless because if that goes down the phones don't work either?
Also, I do not want the traffic of the phones having to come through this network, I want each phone wherever they may be, to go directly through the cloud host only. It is sounding more and more that I may need to switch to another phone solution.

 

[leejor]

While you may be able have a few phones at a location and use STUN, you would probably want any location with more than a few, to use an SBC. You could also use VPN, if available.

So I wanted to host it in the cloud so that phones always work from other locations even if we go down...but with the requirement of having an SBC running...this seems pointless because if that goes down the phones don't work either?

The sets, at locations with power would continue working. If you loose power to the SBC then I assume that the sets and internet connection will also go down at that site, so the SBC is not a weak link. Having an SBC at a location also means that any calls between sets, within that site, do not have to pass through the PBX (voice packets).

The Raspberry Pi SBC is low cost and low power, easily maintained with a small UPS, if other facilities at that site also have back-up power.

 

[SteveITS]

The phones behind the SBC essentially connect through the SBC. It encrypts the connection in a tunnel and the phones are plug and play...plug one it and it shows in 3CX as a new phone. Also calls to another ext behind the SBC do not route audio through the 3CX server.

SBC does have a high availability option where you can put two at each location. It can also be a VM for easy movement/restore.

https://www.3cx.com/docs/3cx-tunnel-session-border-controller/
https://www.3cx.com/docs/sbc-high-availability-cluster/

 

[jfester]

While you may be able have a few phones at a location and use STUN, you would probably want any location with more than a few, to use an SBC. You could also use VPN, if available.


The sets, at locations with power would continue working. If you loose power to the SBC then I assume that the sets and internet connection will also go down at that site, so the SBC is not a weak link. Having an SBC at a location also means that any calls between sets, within that site, do not have to pass through the PBX (voice packets).

The Raspberry Pi SBC is low cost and low power, easily maintained with a small UPS, if other facilities at that site also have back-up power.

Sorry, let me be more specific. We have 2 campuses and users at home. So if campus A has the SBC and it looses power and internet, does that mean that users at home and at campus B also go down and no longer function?

I think you are hinting that no, they would not go down and would indeed continue to work. The 3CX documentation I was reading on the SBC was sorta making it sound that all phones, at campus B and home, would be transmitted through the SBC at campus A. But it seems you are suggesting that I would actually need an SBC at campus A & campus B, all phones at either location would transmit through their own SBC to the cloud, and users from home would not need an SBC and would connect directly to the cloud.
Is all that right?

 

[jfester]

The phones behind the SBC essentially connect through the SBC. It encrypts the connection in a tunnel and the phones are plug and play...plug one it and it shows in 3CX as a new phone. Also calls to another ext behind the SBC do not route audio through the 3CX server.

SBC does have a high availability option where you can put two at each location. It can also be a VM for easy movement/restore.

https://www.3cx.com/docs/3cx-tunnel-session-border-controller/
https://www.3cx.com/docs/sbc-high-availability-cluster/

Ok, so that's excellent as I do have a couple hyper-v hosts at campus A. I was hoping to have no hardware at campus B (it's a new campus we just purchased) other than switches. But it sounds like we must purchase at least an SBC, probably will go with a raspberry pi, or just donate one of mine to the school, rather than getting a computer/server there to host the SBC.

The only remaining question is about users from home. If say, both campus A & B go down, lose power & internet, do users from home still have phones working without an SBC?

 

[Alphabetic]

If your PBX is in the cloud then endpoints connect via SBC, VPN or STUN.

Mobile apps and web client have their own way of tunnelling to the PBX.

Endpoints will proxy through an SBC when set up in SBC mode - if their SBC goes down the phone unregisters.

Endpoints using STUN are independent from everything else and talk directly to the PBX. However, you may encounter issues caused by firewalls which is what the SBC overcomes.

As long as the internet stays up where the PBX is then you'll be able to use 3CX from the web client/mobile app at a minimum if all other SBCs/internet fail.

 

[jfester]

If your PBX is in the cloud then endpoints connect via SBC, VPN or STUN.

Mobile apps and web client have their own way of tunnelling to the PBX.

Endpoints will proxy through an SBC when set up in SBC mode - if their SBC goes down the phone unregisters.

Endpoints using STUN are independent from everything else and talk directly to the PBX. However, you may encounter issues caused by firewalls which is what the SBC overcomes.

As long as the internet stays up where the PBX is then you'll be able to use 3CX from the web client/mobile app at a minimum if all other SBCs/internet fail.

Gotcha! Thank you kindly!

Last question I think: I am going with a raspberry pi for the campus B where there is currently no hardware. For campus A where currently it is on-premises PBX on linux computer, would the recommendation be to keep this PBX only, or purchase a 2nd raspberry pi to have an SBC at both campuses besides the actual pbx?

I am trying to get the authorization to move forward with migrating to a hosted solution, in which case I would certainly get 2 raspberry pi's, just to avoid a mixed setup of different hardware at each campus (campus B on raspberry pi SBC & campus A on linux computer SBC), I'd rather it match at both campuses. I am going to begin searching the forums for recommendations on what vendor to use for hosting as I'm most familiar with AWS & Azure, but am only guessing there are cheaper solutions that specialize in 3CX.

 

[Alphabetic]

You can find hardware spec here https://www.3cx.com/docs/recommended-hardware-specifications-for-3cx/

Since youre running the PBX locally theres no need for an SBC there as you're only adding another point of failure.

once you move it to the cloud you could do. Or, to save on cost, stick the SBC on a VM or Windows Server.

You can install 3CX on any VPS as long as you use the ISO from 3CX so get it as cheap as you like as long as you keep to the specs.

 

[jfester]

You can find hardware spec here https://www.3cx.com/docs/recommended-hardware-specifications-for-3cx/

Since youre running the PBX locally theres no need for an SBC there as you're only adding another point of failure.

once you move it to the cloud you could do. Or, to save on cost, stick the SBC on a VM or Windows Server.

You can install 3CX on any VPS as long as you use the ISO from 3CX so get it as cheap as you like as long as you keep to the specs.

Oh wow they even have the instance types for azure & was listed for the SBC's. Thank you very much for that!

Definitely makes sense what you said, to keep the costs low and being I do have some very nice hyper-v servers, spinning up a VM for the SBC at campus A would be no problem. I do love me some raspberry pi's, so will stick with that for campus B. You've been most helpful, thank you very kindly!

 

[SteveITS]

sorta making it sound that all phones, at campus B and home, would be transmitted through the SBC at campus A

No, they are independent. Each location has its own. Staff at home with desk phones can have an SBC too, potentially installed on their home computer (which would need to be on), but may be fine with the mobile app, or web client if they have a mic.

 

[jfester]

No, they are independent. Each location has its own. Staff at home with desk phones can have an SBC too, potentially installed on their home computer (which would need to be on), but may be fine with the mobile app, or web client if they have a mic.

Good point...we don't necessarily need hard phones if working at home is short-term. We may as well use the mobile client or computer-based telephony. I appreciate that!

 

[JohnS_3CX]

As discussed above it sounds good:

- PBX in the cloud so any site going down will not affect your telephony

- Site A and B can have SBCs to help the desk phones connect to 3CX in the cloud

- Remote workers can use the apps from any location they wish

- Site A and B workers can also use the apps over LTE as a backup, if they lose power/internet in the school or for emergency backup access

 

[Kevin@voxtelesys]

To add into JohnS comment, the home users could use STUN for desk phones as installing an SBC at every home office doesn't make sense.

 

[JohnS_3CX]

To add into JohnS comment, the home users could use STUN for desk phones as installing an SBC at every home office doesn't make sense.

Yes indeed, but I think apps would be a better solution for single users working from home.

Each home user will have a different modem/router/isp combo, and some may block sip altogether, and the user needs to port forward their phone properly to ensure reliability.

It's fine if someone knowledgeable does it for you, but it makes things more complex VS just sending a welcome email and off you go with apps almost instantly coming up online on your PC or mobile device.

 

[jfester]

Yes indeed, but I think apps would be a better solution for single users working from home.

Each home user will have a different modem/router/isp combo, and some may block sip altogether, and the user needs to port forward their phone properly to ensure reliability.

It's fine if someone knowledgeable does it for you, but it makes things more complex VS just sending a welcome email and off you go with apps almost instantly coming up online on your PC or mobile device.

haha indeed! Apps it is for home users!

 

[jfester]

Solved. Thank you everyone!