3CX in a datacenter

[garyjduk]

I have a few questions regarding the pros and cons of moving a locally installed 3CX PBX in an office to a datacenter. I already have a few ESXi servers running in a local datacenter with more than enough capacity to run either just this PBX or even the multi tenant version.

I have a client who up till now had just one office with an internal 3CX PBX using a 2MB SDSL line. This office is in Central London but the SDSL connection has not been great and they have had to change a number of times to a dedicated backup ADSL connection which obviously on another IP address and this breaks the 3CX tunnel connection. The office is with a couple minutes walk of the Mayfair exchange but the connection length is around 1.5km and I'm told it's the routing and some of the wiring maybe old.

So they have 3 internet connections at the minute into the office a ADSL2+ data connection for their computers, a SDSL line for phones and an ADSL backup line. I've also recently seen an article in PC Pro where the head sales guy for the company that supplies these lines said that the SDSL product has never been great. With the introduction of BT Infinity etc I have been asked by the client if they should also be looking to upgrade.

They have now had another office open in Central London and are currently using the 3CX Tunnel to connect the phones from the other office to the PBX. Some calls through this tunnel have had quality issues mainly I think due to the calls going over this SDSL connection twice.

Is moving this 3CX to the datacenter the best way forward? If this was done is the best way to connect the phones to the PBX the 3CX Tunnel or directly?

My thinking is that by moving to say 2 BT Infinity lines with 70meg down 20meg up and introducing a dual band router with QoS and failover etc then if there was a problem the switch over would be automatic.

At the moment they have to physically go to the cabinet and switch modems from the SDSL one to the ADSL backup one and they are not very technical. This would also actually be cheaper than having the SDSL line which alone is about £100 a month. I know the SDSL line has a lower contention ratio but with the issues they are having with it and the branch office layout is this a better option? Each branch office would then have a direct connection to the PBX which is centrally hosted in the datacenter.

Is this change a no brainer with this setup? Is BT Infinity good enough for SIP, this company only have the Professional Edition with 16 simultaneous calls.

Anybody done this before or any thoughts would be appreciated, thanks.

 

[3CXfoxhallsolutions]

Sounds like a 3CX in the data centre is a good idea (especially considering your multi-office needs) ... You then at least have the 3CX and it's line connections (I'm assuming SIP Trunks), firmly connected to Internet with loads of bandwidth available - and good reliability.

Although it may sound like the wrong way to go, I'd plan remote extensions that use the Public IP address of the 3CX to connect i.e. I'd say No to the tunnel! The reason for this is because you talk about dual-WAN and fail-over configurations for your on-premise routers. If you set up remote extensions working either direct with the public IP of the 3CX, or into the 3CX via VPN, then set very short (i.e. 15 - 20 second) updates for the STUN connections - then if the on-premise route does change, the phones adapt very quickly (within the 15 to 20 sec's), and provide the 3CX with the correct routing info to get calls connected.

The other part of this is that you'll need to reduce the registration timer on your extensions, as if you do have a failure that changes the routing to the phone, the phone will only update the 3CX (with the info it gets from STUN) when it re-registers. I'd suggest registration timers set around 90 - 120 seconds.

Using that kind of config, the phones tend to sort themselves out pretty quickly (within their re-reg' period), and as long as you have the WAN change-over / fall-back automated, there is pretty much nothing for the users to do.

I hope that's helpful ...

 

[garyjduk]

Thanks for the comments - I was also thinking of using the Failover Identity function on their Snom phones which I think could route over two seperate tunnels on two seperate WANs.