Mobility is not just about devices, cell phone coverage, MDM and routers. An organization cannot effectively deploy a handful of home based wireless routers and provide a streamlined, high performance and secure service to its users and guests. On the other hand, if the best enterprise wireless hardware is deployed on an aged wired infrastructure, many of the benefits of speed and throughput will be lost. The tone on nearly every wireless project I’ve been engaged in is high profile and high visibility. Wireless is no longer considered a nice to have, or a convenience. It’s a critical part of the infrastructure. As such, the infrastructure that the wireless traffic rides on is also critical. As more organizations deploy new or upgrade their existing wireless to 802.11n standard technology, focus should be placed on LAN throughput, egress and RF planning, and developing a solid strategy for utilizing the 5 GHz frequency.
With 802.11n access points evolving and 802.11ac on the horizon, access points contain more transmitters, combine more streams, and support more optional features of the standard than ever before. However, something that most access points have had even since the pre-standard hardware was released was a gigabit ethernet port. In order to get the most out of your wireless infrastructure, the wired access layer and uplinks to the core/distribution layer needs to be able to accommodate more throughput. Utilizing gigabit ethernet ports on the edge and ether-channeling multiple gigabit or ten gigabit uplinks will prevent bottle necks to the access points and associated users.
Increasing the capacity of the LAN moves the bottleneck away from the APs and up the network stack. The next limiting factor will be traffic traversing outside the organization. Guest users do not only ask for guest wireless, they expect to have it (and by saying guests, it does not only refer to actual guests to the business, but internal users with non-corporate devices). These corporate guests and non-corporate devices require the ability to freely access, have secure sessions, and need more bandwidth for the multitude of devices that they carry. Decisions need to be made whether to tunnel guest traffic back across corporate WAN or to have localized Internet access. Centralizing the traffic can provide benefits for not needing to duplicate systems for firewalling, proxy, web cache or content filtering. However, having guest traffic consume significant amounts of WAN capacity may not be cost effective. Managing separate Internet connections across distributed sites can itself be costly and difficult, but the benefits may outweigh the challenges of having the guest traffic share the WAN.
RF design is a crucial part of the mobility infrastructure. Providing coverage alone is simply not adequate. A single access point could easily cover a 300 seat auditorium. However even half the users were simultaneously watching a Youtube video, how would their experience be? Probably not so great. Considerations need to be made for the density of users and how many access points are within a reasonable signal strength to that area. AP power levels play a very big role in determining how big or small a coverage area will be. A general practice of providing smaller cell sizes with lower AP power is the rule of thumb to follow to not only increase the user density per AP and quality of connection, but providing a lower powered signal will increase the battery life of devices associated to it.
Part of properly designing your wireless LAN is determining how the 2.4 and more importantly, 5 GHz will be utilized. Defining a strategy for 5 GHz will not only future proof a wireless deployment, it will provide the needed capacity to handle the influx of devices BYOD brings to the table. It also provides a band that is far less susceptible to interference. The 2.4 GHz band has many well known interference sources such as microwaves, Bluetooth, game controllers and video cameras. With an ever growing population of non Wi-Fi devices, it is even more important to protect the enterprise wireless devices from these by having a 5 GHz strategy.
The 5 GHz band allows for 21 non overlapping channels in the US. Of those, several can be bonded using 40 MHz wide channels, effectively providing a second channel for bursting traffic. Part of the issue of placing more Access Points in an environment is channel reuse. The air is a shared medium and each channel is a collision domain so same channel overlap should be minimized as much as possible. The traffic that is seen on the same channel but by multiple access points will limit the channel capacity available. With only 3 non overlapping channels in the 2.4 GHz band, providing enough channel separation while providing enough density is a difficult balancing act. Fortunately, the 5 GHz band has many more channels available. It is still very necessary to deploy and support both frequencies for device compatibility. Coupled with a well design LAN and internet edge, this will enable your infrastructure for the performance demanded by the BYOD revolution as well as your enterprise applications.
The complexity of wireless implementation projects I’ve been involved in depend highly on the requirements of each organization. Often, the final design actually removes complexity from an existing deployment while delivering a high performance network. Some projects are a no brainer and others can make for long deliberations over things like the names of SSIDs. While eliminating the bottlenecks and strategizing frequencies is an important part, it’s just the beginning. The success of your mobility infrastructure can and will have everlasting effects. Don’t be left behind with an infrastructure that has not been well planned out and leave those home routers at home.