Is Your Network VOIP Ready

By David Strom Print this article Print

Here are five questions to ask before starting any IP telephony deployment

Enterprises that want to get the most use of Voice over IP (VOIP) need to understand the issues involved in hardening their network and Internet infrastructure before they begin to deploy this technology.

Certainly, VOIP for businesses is on the rise. According to research firm Infonetics, “The overall business adoption of VOIP in North America will increase more than twofold by 2010.” And the Dell’Oro group estimates that IP PBX sales are expected to reach $2 billion by that time.

Here are five questions to ask before you take the plunge.

1. What is your wiring vintage?
Leftover category 3 wiring from the days when Ethernet was 10 megabits isn’t going to cut it, because voice quality will put additional demands on throughput. “Typically, cable plant is an issue for many installations,” says Chad Agate, the CEO of NeoPhonetics, a national VOIP integrator in the Chicago area. “Places that have been using category 3 wiring for 10 megabit Ethernet do not realize that voice is going to need better wiring, like cat 5e or cat 6.” If you want the best voice quality, have as much cat 5e and 6 in your walls as possible.

“The vast majority of VOIP problems that we see have to do with using the wrong cabling or problems in other parts of the local network,” says Henry Kaestner, the founder and CEO of Bandwidth.com, a managed VOIP hosting supplier.

2. Can your routers adequately support Quality of Service (QOS) and virtual LANs for voice applications?
Wiring isn’t your only issue. Depending on the vintage of your network infrastructure, the answer to this question may lead you to an expensive upgrade of your existing routers and switches.

One of the biggest issues with VOIP is understanding how QOS is specified and delivered across your network infrastructure. Voice quality is directly related to network latency and packet delays that can cause drop-outs and degrade overall audio. “We have heard horror stories about other VARs that were really good data guys, but they didn’t understand latency issues and other things that affect voice quality,” says Agate.

If you haven’t paid much attention to QOS before, you will need to spend some time understanding the issues. Several of the better VOIP consultants should be able to help you with this. If your switches are aging, it might be a good time to replace them as part of the VOIP project.

You also might want to segregate voice traffic on its own virtual LAN (VLAN). It’s worth doing a couple of pilot tests before you make any upgrade decisions and redraw your network architecture.

3. Do you need a separate wiring infrastructure for voice?
Just because VOIP runs over an IP network doesn’t mean that you want to share this network with your existing data communications infrastructure. You might think about having a separate wire plant for just your phones, depending on how much of your existing data wiring you need to replace, how many voice users you are supporting and how difficult it will be to bring wire pairs to these phone locations.

Part of the wiring issue is whether you want to deploy Power over Ethernet (PoE) to power your new digital phones. Sure, you can plug them into an AC wall socket, but that might not be convenient or as reliable as having them get their power from a central wiring closet that has battery backup in case of power failures. You may already have PoE installed for your wireless access points or other network devices. Here again, you may be looking at buying new switches to handle this.

4. What is your current Internet connection?
Just like you can’t be too rich or too thin, you can never have enough Internet bandwidth. A good place to start is a free service with TestYourVOIP.com. But you’ll also want to examine your existing ISP contracts too.

“You need a rigorous service-level agreement [SLA],” says Bandwidth.com’s Kaestner. “We have been doing this for five years and have the requirements nailed. We understand the kinds of edge devices that our networks need.”

Make sure you work with providers that understand these SLAs and include performance guarantees in their contracts.

You may be interested in upgrading your existing ISP connection because you have maxed it out. You probably need a dedicated T-1 or better if you are going to have more than a dozen VOIP users, so it might be worthwhile to investigate having a separate ISP connection just for voice.

“Companies are going to need a voice-optimized SDSL line at a minimum for VOIP,” says Kaestner.

“We deliver our VOIP services with at least one T-1 connection,” says Chris Gatch, the CTO of CBeyond, another VOIP provider. Both Bandwidth.com and CBeyond.com have packages that combine connectivity with VOIP services, so it is worth checking these out first.

5. What will you do with your existing analog phones and inbound numbers?
If you have inbound fax lines and analog answering machines that you can’t or won’t get rid of, you need to figure out a plan for either keeping these lines or substituting work-arounds to continue using these phones. The VOIP PBXs also vary in their support for inbound analog lines, something that is also worth investigating.

Speaking of phones, prices on digital phones continue to drop, and Polycom has IP phones that cost less than $150. “This makes it easier for our clients to capture the total cost of VOIP ownership and savings from month one,” says Agate.

Regarding keeping your existing phone numbers, some of the VOIP providers can transfer some of the phone numbers to the new digital lines; some can’t. It is worth checking. There are many reasons why they can’t be transferred: Some are political, some are technical. If you need to keep your existing numbers, you may have to continue to pay your local phone company for minimal service for those lines.

The moral of the story: Don’t do everything at once.

One final bit of advice: It might help to get your feet wet with VOIP and to tackle the project in several stages. (See the accompanying TechKnow story, “Testing the Managed PBX Waters,” on page 48.) Agate suggests that IT managers start off small, by deploying VOIP on the local network first, incorporating a hybrid of digital and analog terminations.

“Then move slowly, using VOIP just for outbound traffic,” he says. An alternative is to use Skype for business and use PCs with their software to make outbound calls.

As you can see, there are a lot of things that revolve around a VOIP deployment, but resolve these issues first and it should go a lot smoother.

This article was originally published on 2008-06-02
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