Routers: A Key Component of the VoIP Ecosystem

Huntsville, Alabama-based ADTRAN Inc. this week released the results of some independent lab testing that pitted its NetVanta Multiservice Access Routers against the equivalent models in Cisco’s newest line, the Integrated Service Routers Gen2.

Enterprise VoIPplanet had an opportunity to talk to ADTRAN’s director of product marketing, enterprise networking division, Rob Snyder, who filled us in on the details of how the testing was conducted—and the results.

The tests, commissioned by ADTRAN, were carried out over a period of several months by independent journalist Frank J. Olhorst, a 25 year veteran of technology testing, and former Sr. Technical Editor of the Computer Reseller News Test Center.

Olhorst paired three NetVanta units—the 4430, the 3450, and the 3430—against their equivalent Cisco Gen2 models—the ISR 3945 G2, ISR 2911 G2, and the ISR 1941 G2.

The basic aim of the testing was to compare raw throughput for each pair of routers.

“We used IMIX traffic,” Snyder explained. “IMIX traffic allows us to have varying packet lengths, as in that way it will simulate what’s happening on the LAN. So I could have a VoIP call, for instance, I could have a Web session, I could have corporate connectivity to a remote office, I could do e-mail, file transfer, and so forth.”

“We tested three scenarios,” Snyder continued. “The first was basic Internet security. We just turned on the firewall—each product has a Stateful Packet Inspection (SPI) firewall—and we turned on Network Address Translation (NAT).”

Another series of tests was done to simulate secure corporate connectivity—using an IPSec VPN with 3DES encryption, in addition to the SPI firewall and NAT.

A third testing scenario was developed using input from IT managers, who felt that their real-world networking experience wasn’t accurately reproduces by either of the scenarios described above. They typically have a 60/40 bandwidth split. [60% FW/NAT to 40% VPN—ca 19:20] They wanted to see a mix, so that’s what the third test was.

“They typically have a 60/40 bandwidth split—60 percent of traffic moving through the firewall/NAT compared to 40 percent moving through VPN tunnels. They wanted to see a mix, so that’s what the third test was,” Snyder told

As you might anticipate, from ADTRAN’s eagerness to publicize the results, the NetVanta equipment outperformed the Cisco equivalents in every single comparison in each of the three testing scenarios.

In scenarios 1 and 3, the ADTRAN throughput advantage was anywhere from double to more than four times that of the Cisco equivalent. In the VPN-only test, results were closer, but, again, ADTRAN equipment prevailed, topping Cisco performance from a bit over 20 percent, to nearly 90 percent improvement.

Snyder attributes the performance advantage to three factors:

First is the operating system, which is “purpose-built, from the ground up,” unlike Cisco’s, which has been adapted to many product lines, as it has grown through acquisitions over the years.

Next is a feature within the ADTRAN Operating Sytem (AOS), called RapidRoute. RapidRoute “interprets” session flows, checking packet credentials only a few times for each session, rather than for each packet. ” We’re able to make higher speed routing decisions,” Snyder said, “and that gives us a performance boost.”

Finally, again, in contrast to Cisco, which, according to Snyder “tries to be all things to all people,” ADTRAN focuses on a very specific market—the small to mid-size enterprise—and a limited number of very specific applications, namely Internet access and corporate connectivity.

In connection with the latter, Snyder pointed out that all the NetVanta routers come with voice quality monitoring as a standard features. “I can track the VoIP call right down to the packet stream, and I can determine latency and jitter – all within a graphical interface,” he said.

Snyder acknowledges that both companies’s equipment has the muscle to handle the applications that are common in the enterprise today. “But what are the future applications?” he asks. “Hosted VoIP, cloud computing—all these other apps that could be applicable in the cloud over time.” All that traffic must move into and out of the enterprise LAN or WAN, all consuming bandwidth and router capacity.

“We can address the bandwidth needs today and into the future, whatever applications they want to put on there,” Snyder concluded.

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