The VoIP management challenge

The Expert Plus version contains the same expert packet- and decode-analysis found in Protocol Expert, but also remotely monitors and even controls other Protocol Expert boxes and handheld OptiView Link Analyzers. Whereas this architecture isn't dedicated to distributed management capabilities (as in the Brix design), it does manage to mirror much of that functionality without a huge investment in new software and hardware.

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It still offers all the usual goodies, including line rate traffic monitoring and traffic capture, packet decoding, Gigabit Ethernet support, and the usual series of network management metrics such as top talkers, VLAN analysis, utilization, and error rate.

Fluke Networks also adds its aptly named VoIP Option. This plug-in software for existing OptiView installations gives network managers many enterprise-oriented VoIP management tools.

With OptiView's history as a protocol analyzer, we expected support for a wide variety of VoIP protocols -- and we weren't disappointed. VoIP Option supports not only SIP, H.323, and Cisco SCCP, but also ASN.1, MGCP (Media Gateway Control Protocol), and SGCP (Simple Gateway Control Protocol). That's more than any other tool we reviewed.

The tool is heavy on QoS validation and measurement, too. It measures real-time QoS metrics for completed calls, initiated calls across most of its supported protocols, and even active calls.

It extends the QoS philosophy to other measurements as well, allowing users to set customer-defined "Quality Grades" for jitter, packet loss, r-factor, and setup time. These measurements can be served up numerically or graphically, presenting calls that measure up to the preset thresholds and those that do not.

In testing, we ran the OptiView a differently, as OptiView's engineer decided to plug the device into the switch port on the back of our Cisco 7960 VoIP phone instead of using a copper tap as we did with Acterna's device.

Under normal circumstances, the OptiView unit would be inserted into a network rack to monitor a SPAN's (switched port analyzer's) port. Indeed, Fluke Newtorks has a copper tap that looks suspiciously like a Net Optics unit, but our engineer didn't use one.

Unfortunately, because the port on the back of the 7960 is a switch not a hub, the OptiView couldn't see both sides of a conversation during monitoring, although it could play back the full conversation later.

After installation, however, the box gave almost exactly the same statistics as the Acterna DA-3400. The Fluke Networks unit did give us an actual MOS score, and the MOS scores were nearly identical to those measured by the

DA-3400, covering both RTP and RTCP to determine call quality by delay and jitter values of the packets themselves.

With the lowest price tag in the review, and the capability to drop its feature set onto a network management solution that large numbers of network managers already own and use, Fluke Networks' OptiView has a big leg up on the enterprise VoIP management market.

Although its features and tools are very similar to those of Acterna's

DA-3400, it manages them in a slightly easier and certainly more accessible user interface. The Brix System is more flexible, but the OptiView has had more time to win the hearts and minds of the same network managers who are now implementing VoIP, especially those from midsize companies looking to maximize their IT budgets.

Spirent Abacus 5000

Unlike the other tools in this roundup, Spirent's Abacus 5000 isn't intended to measure VoIP network quality. Instead, it is intended for manufacturers of VoIP equipment to measure just how well their products meet industry standards. The type of VoIP gear it's capable of testing ranges from small VoIP appliances all the way up to large, telco-oriented VoIP PBX and switching products.

Like most of Spirent's products, the Abacus 5000 comes as a stand-alone box equipped with an expandable port chassis to accommodate multiple test configurations. All hardware is controlled by a dedicated software suite running on an attached workstation using Windows 2000 or Windows XP Pro.