Mitel’s IP-PBX

The Reviewmeister was in dire need of an IP PBX to support a rowdy band of teleworkers, so we tested out several different vendor offerings.

Let’s start with Mitel. Mitel’s Your Assistant software provides a relatively modest feature set, but Mitel is regularly adding more to the package. We were impressed with the call-routing capabilities; call logs and click-on dialing; dynamic audioconferencing of up to eight parties; and the Quick List of close associates, which lets you import contacts from Outlook. The software is well organized, intuitive and customizable.

Most of the teleworker calls we tested used standard vocoders and VPN tunnels, and the per-VoIP-call WAN bandwidth consumption was similar across the board. For example, with the overhead of the VPN tunnel included, a typical G.711 call took about 105K bit/sec in each direction. A compressed G.729 call, also through a VPN tunnel, took about 46K bit/sec.

The exception was Mitel, which does not carry its IP hard phone Real-Time Protocol (RTP) streams in a VPN tunnel. The VoIP connection is authenticated and the RTP streams encrypted, but without the VPN overhead bandwidth consumption drops nearly 20%.

Mitel offers a soft phone for teleworkers, but wanted us to test with just its IP hard phone at the teleworker site. IP hard-phone call quality, in most cases, was good to excellent. In Mitel’s case, we rated IP hard phone call quality as good with G.711, but perceptibly better, good to excellent, with G.729.

When it comes to security, Mitel uses a specialty Linux-based server on the enterprise network, called the 6010 Teleworker Solution, to handle all security and compression (G.729 vocoder) processing for up to 500 teleworker connections. A PC at the teleworker site runs the teleworker applications and connects through a VPN tunnel using the native Microsoft VPN client software, which sets up a more-or-less IPSec-based Layer 2 Tunneling Protocol secure VPN tunnel.

Mitel’s IP hard phone sets up an authenticated and encrypted connection from the teleworker to the 6010 server. It is not a VPN tunnel, though, so it avoids the added bandwidth consumed by VPN overhead. With its lower bandwidth and generally higher VoIP voice quality – as only its IP hard phones were tested – Mitel garnered a high performance rating.

Mitel didn’t provide its soft phone for this review, but the vendor does offer a version of its Your Assistant software that includes a soft phone. A plus for Mitel in this category is its Teleworker Network Analyzer, a small Windows application designed to be e-mailed to teleworkers from the administrator. The applet readily installs, launches a simulated VoIP session back to headquarters and then displays all QoS and connection details.

For the full report, go to https://www.nwfusion.com/reviews/2003/1208rev.html