Yield to Testing: VoIP

Market demand, technological advancements and the statistics that track voice over Internet protocol (VoIP) usage have converged to create some opportunities for you and your customers but only if you yield to testing before entering this progressive intersection.

Growth with a caveat

In general, businesses benefit from a VoIP system that employs one connection to activate a desk phone. A link from the phone to a computer provides network or Internet access. This setup requires half the quantity of station cabling as with separate private branch exchanges (PBXs) and Ethernet networks.

Research analysts say today’s corporate belt tightening is impacting commercial VoIP deployment plans nationwide, but a recent study by In-Stat, a market research firm based in Scottsdale, Ariz., indicates Internet protocol (IP) continues to be a strong—at least partial—voice solution especially for larger businesses. Additionally, broadband IP is fast becoming the most popular provider-based solution. The In-Stat report states “growth in all flavors of VoIP is expected at mitigated levels, reaching 74 percent of all U.S. businesses by 2012.”

Despite this positive outlook, a new study released by Gartner Inc. reports that some commercial enterprises and their integrators still bypass critical predeployment assessments during the VoIP transition. Gartner estimates that, through 2012, up to 70 percent of enterprises that fail to perform an initial network assessment run the risk of additional unplanned costs or deployment delays.

According to Bruce C. Harry, registered communications distribution designer/network transit specialist (RCDD/NTS), director of communications engineering for Fairfax, Va.-based Walker Seal Electric Co. Inc., the most critical step toward ensuring the successful implementation of VoIP into a customer’s existing infrastructure is a thorough assessment and evaluation of the network.

“The addition of VoIP traffic to an existing network will increase bandwidth and resource usage, so it is important to verify that the existing network will support this additional load. This includes not only the layer 2 components, such as the routers and switches, but layer 1 network infrastructure, including the network backbone and horizontal cabling as well,” Harry said.

It’s a big decision to make the shift—even a partial shift—over to VoIP communications that travel on a data network. A seamless flow and transition is always the goal, but integrating voice into the data network without proper network assessments can initiate quality issues in several areas related to power, configuration, security and voice performance.

“The most common problems that we discover are typically bottlenecks, excessive network errors and excessive bandwidth use,” Harry said.

The greatest value of installing VoIP, said Brian Davis, RCDD, a project manager for Electricraft Inc., San Luis Obispo, Calif., is the elimination of recurring costs compared to the traditional Centrex service with a dial tone.

“But there’s a pretty large investment that has to be made in networking equipment, and it has to be analyzed to make sure it can carry the VoIP traffic. Then, because you’re providing power for an IP phone, you have to provide power over Ethernet (PoE) in addition to the cabling,” Davis said.

“For new client installations, we recommend the installation of an open, standards-compliant, structured cabling system with Cat 6 horizontal cabling and 1 gigabit fiber optic backbone cabling as a minimum,” Harry said. “This allows the client the flexibility to transport LAN [local area network] and VoIP traffic on the same horizontal and backbone cabling and it provides them with an infrastructure that is capable of supporting current technologies such as VoIP as well as future technologies.”

Most electrical contractors who install the basic cable comply with ANSI TIA/EIA standards, such as Cat 5e for runs up to 90 meters (295 feet), Cat 6 for additional headroom, and Cat 6a and Cat 7 for 10-gigabit Internet traffic. However, they will generally subcontract the remainder of the installation, testing and documenting to a qualified integrator if profitability and certification become obstacles, said Mark Aceto, operations manager at Black Box Network Services, a provider of comprehensive communications and infrastructure solutions, based in Lawrence, Pa.

“I work on many jobs where the electrical contractor runs the cable and then stops if they do not have the expertise to do the testing. Most contractors know how to conduct tests on the validity of the cable, but in an IP installation, you must connect the routers and PoE switches and that’s almost at an engineering level of expertise,” Aceto said.

However, learning to incorporate new tools that can give a customer an initial look into their network before any installation takes place, can be a logical step toward customer satisfaction and expanding VoIP business opportunities.

Critical network assessments

Experts say electrical contractors certified as RCDD, a growing designation of communications integration, have adopted methodologies to conduct network assessments. Residential network assessments are typically faster and easier, Gartner reports. However, comprehensiveness typically falls short for larger commercial networks with greater performance needs. Audits are primarily designed to ensure that the infrastructure is VoIP-ready from LANs and wide-area networks to desktops and phones as well as completing baseline tests and monitoring actual usage and performance to determine if the data network must be modified to handle voice calls.

Subrata Mukherjee, Fluke Networks’ product manager for copper verification tools, portable network tools and handheld tools, said network assessments for residential and commercial applications vary due to the number of concurrent calls taking place. The demands placed on VoIP traffic run higher than other data transmissions because it is a real-time application.

“If the network is only being asked to handle Web surfing and e-mail, it doesn’t really matter if there are a few seconds of delay in the traffic. But VoIP is a method of transmitting phone calls, and these calls travel in real time. If there is a delay in a part of the call, it is very noticeable to the caller,” Mukherjee said.

Taking a comprehensive network metric approach requires a triple objective: predeployment, during deployment and post-deployment. A predeployment assessment examines all impacts on the existing network environment, including devices, the power supply and cooling and equipment rooms required by the system.

The predeployment phase can be further segmented into what Gartner describes as a three-step comprehensive impact plan that starts with a network topology assessment to ensure that all links have sufficient bandwidth. The second step is a network equipment assessment that checks the suitability of network devices for IP telephony. The third step performs a network voice quality assessment that confirms the network’s ability to transport voice traffic with acceptable voice quality.

“We also test for crosstalk in Cat 5e and Cat 6 cable and measure for alien crosstalk in Cat 6a and Cat 7 cable,” Davis said.

Cut Corners, Cut Quality

According to a 2009 Gartner, Inc., report, “Ignore IP Telephony Network Assessments at Your Own Risk,” skipping a proper networking assessment or cutting corners can compound service problems in the following areas:

• If switches support power-over-Ethernet without sufficient power, supply phones can fail due tointermittent lack of power.

• In large networks, switches may not all be configured appropriately, leading to intermittent voice-quality issues.

• Configuring switches to prioritize voice may lead to degraded performance of other applications if the overall traffic mix is not considered.

• Failing to evaluate existing virtual LAN (VLAN) configurations can lead to phone-connection incompatibility.

• Deciding not to evaluate changes in network traffic patterns can generate capacity contention points and intermittent voice-quality problems.

System vision mitigates future issues

“Electrical contractors can install the basic cable and then let someone else connect the VoIP phone equipment, or they can expand their business by installing, testing and documenting this as part of the cable installation task,” Mukherjee said. “Offering this added service, backed by documented results, allows contractors to bid on more jobs and have a greater sense of security that these jobs will be profitable.”

Gaining a look inside a network that will handle voice applications is the key to preparing it. A new trend is developing where electrical contractors now have the ability to test the performance of the VoIP system in addition to the basic connectivity. Contractors can connect new portable testers, such as Fluke Networks’ NetTool Series II Inline Network Tester, inline for visibility into VoIP calls.

“Tests for key bootup events, such as DHCP [dynamic host configuration protocol] address acquisition, DNS [domain name system] lookup of call servers and gateways, downloading of operating files, and call server registration are critical,” Mukherjee said. “New tools support complete troubleshooting of the IP phone boot process including physical layer tests of structured wiring, patch cables, switch port configuration, VLANs and PoE voltage. It also reduces the risk of a no-charge callback by testing the actual performance while the installer is on-site.”

Portable tools have evolved in recent years to integrate a VoIP log that can display call control events, quality of service (QoS) configuration and call quality metrics. Logs are designed to display important events that occur during each VoIP call, including call setup, configuration and teardown of a call in progress. As the call proceeds, the real-time transport protocol (RTP) configuration is displayed including IP addresses and ports used, virtual LAN priority or differentiated services and codec. Once calls are completed, the log displays the RTP quality metrics such as jitter and dropped packets.

“You can’t expect to be in this business and do it right and expect this type of testing as the technology improves without ever improving the equipment you have,” Davis said. “With the investment in newer tools, you can either test more efficiently at a lower cost or more profitably for the same cost.”

As the electrical contractor’s role expands in VoIP, issues such as training, use of more sophisticated tools and attempting higher level tests will drive new business decisions. But, Aceto warns, the work may not be for everybody.

“You’ll need backend people with a much higher level of expertise and that comes with higher salaries,” Aceto said, adding that over the last five to 10 years, electrical contractors generally ended their role in datacom jobs after they fished cable into a room.

“The phone guy came in and cross connected, and the data guy came in and attached it to patch panel and switched it to a router. Now I guess contractors might be at another crossroads, and the question is, ‘Do you want to go farther?’” Aceto said.

MCCLUNG, owner of Woodland Communications, is a construction writer from Iowa. She can be reached at mcclung@iowatelecom.net.

About the Author

Debbie McClung

Freelance Writer
Debbie McClung, owner of Woodland Communications, is a construction writer from Iowa.

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