Of all the unified communications (UC) platforms on the market, Microsoft Lync is perhaps the most interesting. Unlike all the other vendors that start with voice and then grow into the other stuff, Microsoft starts with desktop applications and then tries to pull voice through. Over the past several years, Microsoft has done a great job of getting Lync on to users' desktops, and now Microsoft and many of its ecosystem partners, such as Polycom and Plantronics, have been aggressively pushing Lync Voice.
There are many things to consider when deploying Lync Voice, such as what phones to use, readiness of the wired network and beefing up the WAN. However, one area that's often overlooked is the WiFi network. In most companies, the WiFi network typically augments the primary wired network. However, for many Lync users, WiFi will be the primary network utilized, given the attractiveness of Lync to mobile workers.
A few weeks ago, at Aruba's Atmosphere conference, I had a chance to sit down with Aruba Networks' John Turner, Solutions Architect and General Manager for Lync Solutions. We discussed the top challenges that face customers deploying Lync as it pertains to WiFi.
His first observation was consistent with what most of us industry followers have noted, and that is that Lync Voice is highly underpenetrated compared to the number of Lync users out there today. This means we should be expecting a big wave of Lync Voice over the next 2-3 years.
With regard to deployment, the following steps were recommended:
• Pervasive coverage is a must. In many office buildings, the offices and cubes are well covered but the "transition areas" are not. Consider a user getting a Lync Voice call while sitting in his or her cube or in a conference room full of people. Not wanting to be rude, the user steps into the hallway or moves away from the cubes, and the call drops because coverage doesn't extend to where that person is. In addition to hallways, consider stairwells, elevators, lobbies and bathrooms. I'm personally opposed to phone calls in the bathroom but have been in plenty of them with people talking on the phone to know coverage is needed there.
• "Densify" the coverage. Although I hate the term "densify," it does accurately describe the requirement. Back in the "old days", when IT actually had some say in the devices being used, there was a certain consistency to the endpoints. The same laptops and Blackberrys were generally bought for all, so the radio quality from device to device was consistent. In today's consumerized business, the quality of radio can vary greatly from smartphone to tablet to laptop. This is why it's common to sit at a desk and have full signal strength on a laptop and poor quality on an iPad. A density of one AP every 50 feet was recommended for the optimal density.
• Access point redundancy. Now that companies are using the WiFi network for mission-critical purposes, the wireless network needs to have the same level of high availability, redundancy and resiliency as the wired network. From a WiFi perspective, this means don't backhaul all of your access points into the same switch. Instead backhaul all of the APs in a given area to 2 or even 3 switches, so when maintenance is being done to a single wired switch it doesn't take down the all of the APs in a given area.
• Beware of Lync video. Most companies take Lync Voice traffic and drop it into its own queue. Then when companies start using Lync video, that traffic is also placed into that same generic Lync queue. This may seem to make sense, but understand that the average Lync voice call uses about 36 kbps of bandwidth, where each Lync video call is about 2–2.5 Mbps. Just a handful of video calls can overwhelm the queue and disrupt all Lync traffic.
Lync video should be classified on its own and separated from the rest of the Lync traffic for optimized performance. This should be considered not just over the WiFi network but also over the wired network, particularly the WAN, where bandwidth tends to be limited compared to the LAN. Not managing this properly can have a significant impact on MPLS costs if the company is paying for any kind of burstable service.
Using Lync over the WiFi network shouldn't be overly challenging for most organizations as long as the right steps are taken. The above should be a great starting point for any company looked to do more WiFi based voice, whether it's Lync or any other UC solution.
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