Sizing up VoIP servers
3Com, Avaya, Siemens, and Zultys offer rich telephony features, excellent voice quality, and more or less scalabilityFollow @infoworld
One nice feature of the management tool is the ability to monitor environmental conditions in the room in which the PBX is installed. That way, you can take steps to cool down the server room before it gets too hot and the PBX shuts itself down.
Once networked, the Avaya PBXes acted as a single unit. Although we performed this test within the lab at the University of Hawaii, it's clear that you can network these products over far greater distances, preferably using a leased line rather than the open Internet. Avaya says that both the S8300 and the S8700 have the ability to work with virtually any legacy PBX currently in the marketplace, which means that you don't have to replace your phone system to start using VoIP and can instead hook up the Avaya and slowly migrate.
Siemens HiPath 4000
The HiPath 4000 is another mega-PBX that can be configured to support as many as 100,000 users if several of the units are networked together. The individual HiPath 4000 that we tested can support up to 12,000 users. The HiPath 4000 can also be used in conjunction with the smaller HiPath 3000, but we did not test this arrangement. Both models use the H.323 protocol to transmit calls, but they don't support SIP.
Click for larger view.
Because the HiPath 4000 uses some proprietary extensions to the H.323 standard, we couldn't run most of the Abacus performance tests. However, we were able to test voice quality, which proved to be excellent. The HiPath 4000 supports standard QoS so you can share your voice and data infrastructure, as long as your switches are set to work with standard 802.1p and 802.1Q prioritization. Of course, such operation isn't recommended because voice traffic can be very sensitive to bandwidth restrictions, but it's nice to know you can do it if necessary.
While the Siemens management utilities aren't the sexiest on the planet, they are perhaps the best documented. Help files and tutorials abound, they're easy to access, and they're complete. You can interact with the HiPath in German, as you'd expect, and also in English. In a recent improvement, even the command line interface now works in English. One quibble: Some pop-up messages still appear in German.
You set up the HiPath 4000 by following a well-designed wizard that leads you through the steps. The management interface consists of a straightforward Web-based GUI; you select options from lists and drop-down menus. Help is available everywhere and you get confirmation boxes where necessary. Training IT staff to manage the HiPath should be a piece of cake.