Calls between PBXes

[xptpa2020]

We have our hosted corporate PBX in the cloud - it is doing great.

We have a “demo” PBX kit we take to client locations for pre-sales demos. This kit consists of a local atom box, running FreePBX V13 and various phones. Using the demo kit ensures we control the demo and that all PBX call functions are doable - no client Watchgaurd firewall “shutting down” our demo, because it runs on our own local network at the client site. In that demo kit we have a router - that router’s WAN connects to the client’s LAN. If the client’s FW is not blocking us, an IAX trunk is preconfigured to talk to our Corporate PBX in the cloud and pass traffic for outbound calls. On Thursday we would like to demo inbound calls with Zulu and Screen pop for their CRM. I am not too sure how to configure the trunks to pass the inbound calls fromt the Corp cloud PBX to the demo kit.

We have a test DID on our Corporate PBX. The demo kit PBX will be double NAT’ed and we will have no control over the outermost firewall in that setup. Can I route an incoming call to the test DID, to the Corp PBX, over the IAX trunk, across 2 firewalls, to the Demo FreePBX at the client site for the demo. Just typing that makes me think not.

Opinions are appreciated.

[dickson]

Personally I’ve had AMAZING luck with IAX, my go to protocol for any inter asterisk connections. I’ve talked on it using an old version of “FireFly” IAX client from airplane WiFi.
It would be my first go to choice. Its generally very firewall and NAT friendly.

Build your IAX trunk, shouldn’t be a problem at all.
have you considered slaving a Mobile phone data plan to your demo customer PBX and just bypass their network completely just in case?

[Stewart1 (Stewart)]

IAX is very robust and multiple cascaded NATs should not be a problem at all. In your Corporate PBX, just configure an Inbound Route for the demo DID and set the Destination to Trunks, [your IAX demo trunk]. Of course, test the demo system thoroughly, e.g. at home, before showing it to the customer.

While IAX will most likely make it through the customer’s firewall, you probably won’t get the benefit of any QoS they may have; be prepared to explain the cause of any voice quality issues and why they won’t be present in a production system.

I agree with @dickson that mobile data is a good fallback, though it’s even more likely to have less than perfect voice quality.

Here are some suggestions for a cover-all-bases demo system. You probably won’t be able to implement it for your Thursday demo, though it may be a worthwhile setup for future presentations.

Set up a VPN server on your cloud PBX and a VPN client on the demo; this will cover the case where outbound VPN is allowed but IAX is blocked (not explicitly; some firewalls block all UDP ports that are not specifically permitted).

You might also set up trunks on the demo system directly to providers, in case of an issue with your cloud system. VoIP.ms offers IAX trunks; MRC with one US DID is only ~$1. CallWithUs offers OpenVPN access; MRC with one US DID and VPN option is ~$6.

Consider a router that can be configured as a Wi-Fi client such as https://www.amazon.com/Mikrotik-hAP-AC-Lite-RB952Ui-5ac2nD/dp/B019PCF3QY . You would then have the option of a wired connection if the customer can provide one, connection to customer Wi-Fi, or connection to a hotspot from your mobile phone. If possible, bring along two phones on different operators and choose the one with the best LTE signal.

[PitzKey (Itzik)]

Honestly, i would rather have a VPS demo, and schedule with their IT to be available at the time of the meeting in case their firewall blocks access to the VPS.
Having a demo with failed incoming calls is no good impression…
Or go with the mobile data… but please head to their parking lot a day before to test the call quality

[dickson]

QoS wont’ be an issue not for a few demo calls. Can’t QoS across the internet anyway and if a customers network is so bad that you need to worry about Qos to get a phone call to work, they’ll be a difficult customer anyway with substandard networking practices.

Mobile data will not affect voice quality, with the assumption that your network carrier gives you more that 100kbps. I use SIM enabled routers all over Asia for voice trunks over internet, perfect for SIP and IAX.

Using a 3rd party provider isn’t a bad idea, but since you have already opened up your far end PBX then you probably wont have a problem.

If you are looking how to make the calls work between your two systems, heres how!

Build your IAX trunk between your two sites to be as dynamic as possible. This way, especially at the customer demo side, you wont care about what the external IP is.

CORPORATE SIDE make an IAX trunk using these settings!
Create a new IAX TRUNK in FreePBX
(GENERAL TAB)
TRUNKNAME=demotrunk
DISABLE TRUNK= NO
(IAX SETTINGS TAB)
TRUNKNAME=demotrunk

PEERDETAILS:
host=dynamic
username=demotrunk
password=blahbahayaddayadda
context=from-internal
type=friend

SUBMIT and SAVE these changes

DEMO PBX
Create a new IAX TRUNK in FreePBX
(GENERAL TAB)
TRUNKNAME=demotrunk
DISABLE TRUNK= NO
(IAX SETTINGS TAB)
TRUNKNAME=demotrunk

PEERDETAILS:
host=X.X.X.X (IP OF YOUR COMPANY)
username=demotrunk
password=blahbahayaddayadda
context=from-internal
type=friend

NOW CLICK ON THE INCOMING TAB !!!
REGISTER STRING=
demotrunk:[email protected] (this is your corporate IP HERE)

SUBMIT and APPLY your changes.

This type of IAX trunk should allow the "demo" side of your pbx to register to your corporation and use whatever WAN side IP its detected. This way you dont have to worry about programming the IP in your corporate PBX connection. You can use a mobile hot spot or whatever, the system will register as that IP.

ROUTING OF CALLS
On the corporate PBX create an outbound route that points to the IAX trunk you just created, and in the dial pattern, just put in the “match pattern” of the extensions at the far end. So if your demo PBX uses extension 4455 just put that in the that box and submit/apply the changes. Or you can do “4XXX” if you want to match everything from 4000-49999

On the DEMOPBX side, you can do a similar thing should you want them to make calls back. So if your extensions on the corporate PBX side are 7000-7999 put in 7XXX in the outbound routes of the demopbx, and the phones can call back.

[Stewart1 (Stewart)]

@dickson , +1 on the IAX setup.

@dickson

QoS wont’ be an issue not for a few demo calls.

I disagree here. A small organization may have DSL or low-end cable service with only 1 or 2 Mbps upload. They’re probably using an ISP-supplied modem/gateway with big buffer bloat. Any significant upstream activity, e.g. a file saved to Dropbox or emailing a document could seriously degrade outbound quality of even one call. This isn’t directly what the prospect hears and may go unnoticed, but if he calls his buddy and is told “hey, you’re breaking up”, be prepared to explain why this happens and why it won’t occur on a production system.

@PitzKey

head to their parking lot a day before to test the call quality

For sure, but take into account attenuation by the building. If your LTE signal is weaker than ~-110 dBm in the lot, it likely won’t work well inside.

In case you can’t get decent Internet connectivity, set up extensions that route to the demo IVR, queue, etc. so you can show off all the bells and whistles using internal calls.

[dickson]

That is completely true, production yes for sure you need QOS. I was approaching his situation from a demo perspective. If call quality is bad, it could be quickly identified as a firewall or bandwidth issue. This is why i didn’t go on about QoS. Once you SELL the customer the product, then you make sure you got QoS in place and some minimum bandwidth recommendations.