In this test we compared the telework offerings of five leading IP telephony vendors - Alcatel, Avaya, Cisco, Mitel Networks and Nortel - under real-world IP WAN conditions.
IP telephony is extending new features and capabilities to mobile employees and road warriors, and revolutionizing the way teleworkers connect and work with their counterparts back in the office.
In this test we compared the telework offerings of five leading IP telephony vendors under real-world IP WAN conditions. We found that the vendor packages - from Alcatel, Avaya, Cisco, Mitel Networks and Nortel - vary in their security infrastructure; recommended equipment; breadth of new applications and features; price; and quality of voice communications.
How we did it
Kudos to Nortel, the Network World Blue Ribbon winner with its MCS 5100 - a new SIP-based IP PBX and applications platform. Nortel earns high grades for its collaboration features, including videoconferencing, instant messaging, whiteboarding and Web co-browsing.
Avaya and Mitel also scored well. While neither offered as rich an application package as Nortel, Avaya's teleworker package delivers excellent call routing and mobility features, while Mitel's PC software included impressive call-handling capabilities. We also gave Cisco high marks for its call-routing capabilities.
We defined our review criteria in four general areas (see scorecard, below).
• Telephony features and collaboration features.• Hard phone and soft phone performance.• Configuration, integration of components, setup and monitoring of teleworker connections.• Security provisions for protecting the teleworker's IP connections.
In this test, each vendor first had to set up a full working IP PBX in our lab. Then they had to set up whatever remote-site equipment and software they recommend and offer for telecommuters. A Cisco IOS-based router infrastructure connected the enterprise IP PBX LAN with the "remote" teleworker site, simulating connectivity through one or more ISPs. A special simulation system, from PacketStorm, applied consistent WAN impairments to all passing voice-over-IP (VoIP) traffic. (See How we did it).
What features matter to a teleworker? We decided anything that enhances productivity, lessens the physical remoteness of the teleworker, or enables closer communications and collaboration with fellow workers back at the office was a good candidate.
Nortel's Multimedia PC Client, with an integral component called the Personal Agent, addressed all these areas. Presence - where the real-time status of workgroup or department members are propagated to all other members - is well implemented and effective. Other nice features are call routing, which lets you define various call-handling responses based on factors including who is calling, videoconferencing, instant messaging and whiteboarding. There's even "Web-push co-browsing," where multiple remote users can concurrently browse the same Web sites.
The Avaya features, included in the $150-per-PC Mobility Package, include a soft phone and routing features that connect and transfer calls to the teleworker's cell and home phones. There's also IM and a unique feature that integrates phone numbers embedded in Web pages with the soft phone, so you can click on and dial any phone number you see while surfing the Web. Other well-done, useful features include the six-party audioconferencing and integration of the Avaya applications on the desktop with Microsoft Outlook.
Mitel's Your Assistant software provides a more-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.
Cisco's features are distributed over several disparate applications, including the soft phone and the Cisco Personal Assistant. There is also access to the vendor's Unity unified-message store via the Web interface. Unity provides a text-to-speech capability for retrieving e-mail by phone. Cisco's call routing is among the richest of all the vendors reviewed, providing the broadest set of rules-based call handling. For example, you can have your calls go to voice mail in the morning and then sent to your cell phone in the afternoon. There's also a noteworthy personal address book tied into telephone functions.
Alcatel says it has several new messaging and collaboration applications coming out early next year. But for now, we tested the features of its soft phone package, OmniTouch MyPhone. The software lets the teleworker closely associate his IP soft phone with other public switched telephone network (PSTN) connections, including cell phone. An impressive feature is the ability to pass a live call from the IP connection to a PSTN phone if IP call quality degrades.
As most of the teleworker calls we tested used standard vocoders and VPN tunnels, 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 drops nearly 20%.
Call quality varied significantly in some cases. Avaya's less-expensive IP phones, the 4602, priced at $195, delivered poor-to-fair call quality with compressed G.729 vocoding. Call quality with Avaya Model 4620 IP phones, twice the price of the 4602, consistently yielded good calls. Avaya says the two phone models implement vocoding algorithms differently, which is not typically the case with VoIP products from the same vendor.
The soft-phone call quality was generally worse than with hard phones. The mediocre headset we used for all our soft phone calls no doubt contributed to this result, but we advise readers to consider offering their teleworkers the option of an IP hard phone, too, even though they might use a soft phone.
Nortel had the best soft-phone call quality, with good-to-excellent ratings for both G.729 and G.711. Avaya's was good to excellent with G.729, but only fair with G.711, which was surprising. Alcatel's soft phone yielded fair-to-good call quality with G.711 and poor-to-fair for G.729. Cisco's soft-phone call quality was poor with G.729, but fair with G.711. 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. Nortel's hard phones yielded good-to-excellent call quality in all cases, as did Cisco's.
Teleworking through tunnels
We required vendors to deploy the security infrastructure they recommend to customers who need to support teleworkers. IP Security (IPSec)-based VPN tunnels were the choice in all cases. Mitel used VPN tunnels only for PC connections; the VoIP streams of its IP hard phone did not travel through VPN tunnels. Cisco and Avaya deployed VPN client boxes at the telecommuter site. These devices - a Model 831 IOS-based Secure Router in Cisco's case and SG5X Secure Gateway in Avaya's case - include a multi-port switch, perform encryption and authentication for a few concurrent VPN tunnels, as well as network address translation, Dynamic Host Configuration Protocol, IP routing and, to a user-defined extent, firewall processing.
Alcatel recommends IPSec-based VPN tunnels, but doesn't offer its own VPN equipment. Instead, Alcatel certifies that its VoIP equipment and OmniPCX will work over specific third-party VPN packages. Because the vendor didn't bring any VPN gear, we tried a low-end Linksys IPSec-based package under Alcatel's teleworker VoIP connection. The Linksys VPN gear wasn't on Alcatel's list of certified VPN hardware, but it worked fine.
In Mitel's case, a specialty Linux-based server on the enterprise network, called the 6010 Teleworker Solution, handles 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.
Nortel's PC software is multifaceted and well engineered. Nortel's VPN client software, which comes free as a component of its Contivity VPN hardware package, handles all security processing for both the PC with soft phone and an optional, attached IP hard phone, rather than having a VPN box handle it. In addition to the soft phone, Nortel's PC software package, called the Multimedia PC Client v2.0, also includes the smarts to handle SIP endpoint call processing.
So all there is at the Nortel telecommuter site is the PC - running all of Nortel's client software and soft phone. If not plugged into the WAN link (via cable or DSL modem, etc.), the PC could be plugged into the switch port of the optional IP hard phone. In either case, all traffic between the teleworker site and the enterprise network is protected through the Contivity VPN tunnel.
The packages tested could all successfully deploy their security and teleworker VoIP connections over the Cisco router infrastructure.
In the configuration category we considered the hard and soft phone options, the integration of the components, and the setup and monitoring of teleworker connections. While there was some diversity, overall we rated all the vendors on the same level in this category.
We did not test Alcatel's teleworker configuration with a hard phone, but the vendor does support a hard phone and soft phone combination. Alcatel's score here was compensated by excellent setup wizards for its soft phone, which assures optimum sound and voice quality.
The ability to tune Avaya's soft phone for optimizing call quality is also noteworthy. The administrator and the teleworker can readily modify vocoders, even adjust receive and transmit gain (volume) levels. Avaya, too, lets the teleworker closely associate the IP soft phone with an IP hard phone, home phone or cell phone. The teleworker can retrieve some rudimentary real-time quality-of-service (QoS) data from the soft phone, too.
Cisco recently revamped its soft phone structure, going from the previous TAPI-based software to new code that directly interacts via the Cisco "skinny" call-control protocol, formally called SCCP. Some adjustments are clearly still needed, because Cisco's soft phone call quality needs work. Cisco's IP hard phone performance remains stellar, however. Cisco's wealth of security options, and its bandwidth management and QoS features are more extensive than its IP-telephony competitors. But all that functionality leaves customers with a lot of pieces to manage and many different interfaces through which to do it.
Nortel's well-structured PC software includes the video coder/decoder, and the bandwidth required for the video portion was in the range of 40K to 80K bit/sec. With the very good soft-phone call quality, an IP hard phone at a teleworker site might be unnecessary, although it still offers improved connection quality.
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.
The leading IP-PBX vendors all have a story to tell for extending VoIP out to teleworkers. But their on-site teleworker packages vary considerably in equipment and configuration, feature, price and relative call quality. Soft-phone call quality was best with Nortel, followed by Avaya, Alcatel and Cisco. IP hard phone call quality generally was better and more consistent across the board, al-though there were noticeable differences with the two vocoders we tested and between Avaya's different IP-hard phone models.
Avaya and Cisco, prefer a multi-port VPN box at the teleworker site, while Nortel and Mitel employed PC-based VPN client software in our testing. Otherwise, all the vendors endorse and support IPSec-based VPN tunnels for securing teleworker-to-headquarters VoIP connections.
Readers will find that new applications and features, for conferencing and collaboration, are the area where IP-telephony is delivering the most tangible - and impressive - new capabilities to teleworkers. We found Nortel's current offerings to be the most developed and capable of enhancing the teleworker's productivity and environment. But competitors are gaining quickly.
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Mier is president of Mier Communications, a network consultancy and product test center based in Princeton Junction, N.J. He specializes in VoIP product analysis and IP-telephony consulting. He can be reached at firstname.lastname@example.org.
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