Planning ahead for gigabit wireless LAN migration

In the era of gigabit wireless LAN migration, it is important to recognize key details of this kind of investment, and be prepared for 802.11ac and 802.11ad standards.

In part one of this series on gigabit wireless LAN, we reviewed how 802.11ac and 802.11ad standards would work

in enterprise Wi-Fi networks. In part two of this series, we explore the steps that engineers can take to plan for gigabit wireless LAN migration.

According to In-Stat, the gigabit wireless LAN market is poised to reach nearly 1 billion users by 2015. It is possible for engineers to plan now for gigabit wireless LAN migration using 802.11ac and 802.11ad standards.

Is a gigabit wireless LAN migration really worth the investment?

Network engineers still in the throes of 802.11n deployment might be wondering whether they'll really need the added speed and capacity of 802.11ac anytime soon. But the answer to that is pretty clear, according to Matthew Gast, Aerohive Networks director of product management.

"I've been in the [LAN] industry for a little over a decade, and I've never gone wrong making a bet that people will want to send more data next year," said Gast.

In fact, enterprises have already started to move in directions likely to prove Gast right, given that most reliable 802.11n wireless LANs that deliver broad coverage throughout business environments, applications and devices are rapidly migrating onto wireless without a backwards glance. From video conferencing to virtual desktops, mobile devices are gulping available bandwidth almost as fast as it can be rolled out. For millenials now entering the workforce, the very idea of being tethered to the wall by an RJ-45 jack seems antiquated.

"As long as we continue to use email as our default file sharing method, we'll be sending richer graphics that create larger attachments. We'll also continue to move to battery powered devices like iPads, especially in combination with desktop sharing, so that what we'll be sending over the air more and more is screen scraping," said Gast. "This is particularly prevalent in healthcare, where you're taking data and locking it away in a data center, only providing access to it through remote desktops."

Another trend likely to escalate bandwidth demand—both at work and at home—is cellular network offload. At both venues, Wi-Fi consumer electronics are sprouting like mushrooms after a warm rain. This in itself increases demand for Wi-Fi bandwidth.

Mobile broadband may be ideal for on-the-go connectivity, but carrier tariffs encourage users to route as much as possible—data, video and voice—over "free" wireless LANs instead. At home, offloaded traffic ends up routed onto residential broadband. At work, Gast expects to see offloaded traffic heading through "employee hotspots" onto corporate wireless LANs— or at least segments designated for that purpose.

Getting ready for 802.11ac and 802.11ad standards

As with draft 802.11n, enterprises are likely to defer major investment in 802.11ac until the standard reaches maturity—or at least until the Wi-Fi Alliance has established a certification program. The latter is important for interoperability—not just between 11ac devices, but for peaceful coexistence with deployed 11n devices in the 2.4 and 5 GHz bands.

Maturity also tends to drive down chipset, and therefore Wi-Fi device cost. Enterprises that only recently purchased 802.11n infrastructure may want to get five years from that investment, but that doesn't mean they should wait until 2015 to start 802.11ac planning. As draft products emerge, network engineers should begin lab tests and small trials, learning how to best share available spectrum across applications with diverse needs. Correctly matching app throughput and latency requirements to 11ac stream, coding and channel width permutations will no doubt benefit from practical experience.

During this timeframe, IT should start thinking about how new devices, applications and approaches to information delivery and storage could benefit from 802.11ac. For example, streaming video required by webcasting is easy when compared to the per-participant video mixing required for true video conferencing. Collaborative applications like video conferencing and virtual whiteboarding have promise that cannot be realized until network infrastructure is ready to handle that workload. Ditto for virtual desktops. However, moving an entire workforce to virtual desktops could take years—by which time 802.11ac products should be ready to roll.

Beyond thinking ahead, network engineers should be actively laying the groundwork to support very high throughput wireless. For example, any organization now planning a LAN edge refresh is no doubt trying to decide between 100 Mbps Fast Ethernet or Gigabit Ethernet (GbE). "If you've been putting off GbE, you definitely need to do that now, especially if you want to future proof your LAN," recommended Gast. "I'm sure we'll make 11ac APs plug into Fast Ethernet, but at some point, it just doesn't make sense to do higher rates over the air unless you can match them across the backbone."

Another constraint that early 802.11ac deployments are likely to face is power. "This happened with the first wave of 802.11n for pretty much everybody—those APs were power hungry and had to work in slightly less efficient modes [when powered by 802.11af]. This will probably be true for the first generation of 802.11ac devices as well," said Gast. To increase available power supply, network engineers should require 802.3at PoE+ in all future Ethernet switch upgrades. This may provide extra ammunition for GbE, since Fast Ethernet switches are not moving as rapidly to support PoE+.

We've been down this road before. Bringing 802.11ac and 802.11ad to market and getting enterprise networks ready to handle it bears a striking resemblance to the road we just traveled for 802.11n. Hopefully, the industry has learned from that process, helping us navigate this migration more smoothly. For network engineers, there's nothing like the luxury of lead time—don't assume today's highways will be wide and fast enough to handle tomorrow's traffic. Now is the time to start planning for 802.11ac.

About the author: Lisa A. Phifer is president of Core Competence Inc. She has been involved in the design, implementation and evaluation of data communications, internetworking, security and network management products for more than 20 years and has advised companies large and small regarding security needs, product assessment and the use of emerging technologies and best practices.

This was first published in May 2011

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