Despite the proliferation now of broadband, in many cases and partly thanks to the massive increase in video usage, bandwidth is still at a premium, especially in the still ubiquitous world of ADSL broadband technology where uplink speeds are often very limited.

This causes problems when trying to combine multiple voice calls with concurrent data activity. Despite voice compression techniques taking bandwidth requirements, per call, down to a mere 8Kbps, in reality the overheads involved in packaging the voice mean that each calls uses at least five times this bandwidth. At 40Kbps+ per call, a typical ADSL uplink cannot support many calls.

With no Quality of Service (QoS) available, any data transfer activity impacts hugely on voice calls, making true concurrent voice and data activity impossible beyond very low call/data levels. Even with standard QoS enabled, at typical ADSL uplink speeds, the impact of the QoS parameters is negligible. Worse still, some operators do not support QoS across all links and inherent limitations mean that the maximum number of concurrent calls that can be made is very low.

UK start-up Voipex is claiming to have a solution to these issues in the form of its ViBE technology tested here. Pricing starts at £299 for a CPE appliance and £450 for a head end device (supports up to 200 calls).


With ViBE, Voipex has created an alternative QoS technology that is designed to operate successfully at much lower bandwidth availability rates than standard QoS mechanisms.

Using intelligent header compression and other optimisation techniques, Voipex claims that by handling voice as a very specific application, it really can minimise bandwidth usage down to the 8Kbps that a G.729 (compression standard) voice call technically requires and not the 40Kbps+ normally found in practise.

The ViBE technology is also very flexible in that in can be deployed in a very broad range of environments, such as point-to-point, hub-spoke, private/public network, managed service, internal service…

While designed for use with all sizes of company and device (from basic router to rackmount appliance) it does feature enterprise-level redundancy, such as its RAIN option – basically the equivalent of a RAID architecture in the server environment – allowing redundant connections.

Another benefit of this architecture option is that it can further significantly reduce the common issue of random packet loss on relatively low or poor quality broadband connections. Indeed, the ViBE technology itself is largely network agnostic. Voipex has deployments over satellite links, for example, showing enormous cost savings compared with the alternative of adding bandwidth to solve the problem.

Management options are via SSH console or browser-based GUI. Focusing on the latter, the interface centres around a two-tier menu. Highlighting an option at the top level reveals a dedicated sub-menu beneath for each top tier option. Top level options cover Info, Graphs, Status, Log which are focused on status checks and System, Network, Firewall and ViBE, which are focused on configuration.

Importantly, link stats are available from the ViBE menu option providing valuable information. The stats are available in what are defined as standard and extended format, and include placket loss, round trip times and jitter levels.

In order to test the claims of Voipex, we created a test bed, based around a very typical configuration—effectively a branch office or small business (Birmingham) connecting to a hosted ViBE server via a DSL Max service (Docklands), in turn connecting to an Asterisk server via a second ViBE appliance at a remote site (Milton Keynes).

On our live network and were able to generate in excess of 40 calls up a 448Kbps (as measured by ourselves) ADSL uplink, with concurrent data traffic and recorded zero packet loss. As more voice calls are brought up, the bandwidth made available to the data traffic is automatically reduced to allow bandwidth for the extra voice calls, but data applications were maintained throughout testing, with no failures.

We confirmed voice call quality with live calls as part of the test and heard no sound degradation whatsoever, even with over 40 concurrent calls up. The technology itself is also very flexible. It is available in a very low-cost, small form factor appliance, as well as in rack mount format for enterprise, ISPs, Hosting companies etc, so is both inexpensive and scalable.

Note that the appliance is a full-function router, so is a true technology replacement option, not simply an additional “black box”. We also saw the ViBE technology working as an integrated, additional application on a standard Netgear ADSL router. Integration of the ViBE code with any Linux-based appliance is not only possible, but very uncomplicated.


With ViBE, Voipex has finally given meaning to VoIP in providing a real, cost-effective and technically superior alternative to classic voice that isn’t just hype. Realistically, this is technology that should be sitting on every router. To not take advantage of the ViBE technology would be a criminal offence in that it denies the user base serious economies. Can we make it a chargeable offence not to deploy it?

  • Greg Genge

    This is an amazing product, I have seen it working, why is not everyone using this??