Thursday, May 10, 2012

My first VoIP phone

Following attendance at the Unified Comms Expo in London back in March, I had a curiosity to look at VoIP (you'll need to sign up to playback the video) and see what I could play with in free time. I decided to start with a my own number with a desk handset + headphones from my home office.

Previously, I'd had frequent problems using the ClearOne wireless starphone on my main phone line at home. It was mainly issues the audio quality of the wireless exception. Call/audio quality was ok when the mute button was on, but when I left it off (I sit and talk on a lot of conference calls as part of my job), the call audio quality was terrible. Again, don't think it was the line as the DECT phone and other land-lines extensions were all good.  Possibly wireless interference.

I bought a Snom 300 and MM3 headset from my ISP. Fully featured and supports all the key codecs for VoIP and SIP. My ISP also provide SIP servers and the Snom was recommended and worked great in their environment. I had one VoIP number which was configured on the Snom 300 when it arrived. I simply plugged in the ethernet cable in which connected to the office switch and picked up a dynamic IP. The ISP customer broadband control pages allow you to configure inbound and outbound rules alongside general security of your VoIP line to ensure it does not fall into the wrong hands and run up a very large bill without you knowing. Easy.

Spec wise, their call servers use G711 within SIP/2.0 protocol for 64kps data for calls. Call plans for PSTN calls are competitive and given I had several calls to US and UK audio conference providers over a major incident spanning a weekend, and it worked a treat.

All in all, much better to hog my own office line at home, and leaving the analogue line free for the family. Cost wise, the ISP telephone call costs are itemised and its straightforward to claim business calls (not the line itself of course) on expenses. It's better than running a 2nd home phone line with BT (line rental and calls).

However, there were an few interesting things, I wanted to get sorted:
  1. Inbound calls - when testing, I found I couldn't call into the VoIp number as it simply wouldn't respond  Why was that?
  2. Mobility - wouldn't it be great to not be tied to the desk, but use softphone clients?
  3. Security - should I be worried about eavesdropping on my calls over the net?
Inbound calls
Basically, I found this was due to standard NAT being enabled on my router (Billion 7800N). That is, it can't route back to an internal IP from the outside world. NAT is seen as traditionally evil and a cause of lot of broken VoIP/SIP set ups. I'm actually one of the lucky ones to have a router which supports Application Level Gateways (ALGs) for common port mapping functionality which is useful for SIP.  It was just a click of a radio button to turn it on the router admin pages. I'm told ALGs functionality on manufactuter routers for SIP can be flaky sometimes and vary in terms of their implementation to a standard. Luckily for me, I didn't need to do a whole bunch of firewall rules from my ISP to allow inbound calls on the VoIP side.

Mobility
I was recommended the Bria client on both iPad and iPhone. Works beautifully. Very quick to set up your VoIP number and SIP provider details. Even plays nicely over 3G. I now have some flexibility to get local cost business calls regardless of location (toll bypass anyone?). Take a look at Counterpath, they seem to have a whole range of VoIP/SIP software solutions.

Security
Beyond password as a basic security, I did consider encryption of the tunnel to the external SIP servers and encryption of actual voice data (not that I'm doing anything classed as sensitive or requiring to be that secure).  TLS and SRTP are the transport protocols here. I trusted my ISPs guidance that there was little chance of anyone intercepting the traffic between  me and their SIP servers, but I'll keep an eye on this one.

So all in all, a good investment. Set up cost was about £165 (Snom 300, Headset, Bria clients for iOS).  Recurring costs wise, the number is about £3 a month + calls on a transparent call plan. I haven't measured the ROI, but it makes more sense on the VoIP as opposed to the waste on line rental charges and all inclusive call plans with BT.  Of course, in terms of resilience, I may want to look at a back-up ISP I lose my broadband connection with the ISP. The Billions can accommodative an simultaneous ADSL connection at the same time as a fail over. Seem ominous I'll look at this at some stage, although again it need a 2nd phone line with all the fixed charges which come with that.

Plus it's more tech to babble about ;-)

2 comments:

  1. Sounds pretty sweet set up. This an area I am not that familiar with. I have a wireless IP phone that is part of my BT HomeHub. It seems as if you have replicated the same deal. Is that correct?

    I will ping you my IP number so we can test it the quality out one day. Also I have questions about the use of the iPad app.

    ReplyDelete
  2. Yup, IP phone is an IP phone, so you will have a SIP registration of the wireless phone with your ISP. Also you will really like the Bria soft phone app.

    ReplyDelete