802.11n MAC MSDU integrity
If you don’t know where you’re going, you’ll end up someplace else.
—Yogi Berra
Although most of the discussion in this book has been about speed, the real value of 802.11ac to the network administrator is that it increases the capacity of a wireless network. Whether the network needs to serve more clients with today’s level of throughput or today’s client load with higher throughput, the solution is 802.11ac.
Several intersecting trends are driving the need for increased capacity. Many new devices are built around the assumption that 802.11 coverage is ubiquitous and therefore do not have an alternative LAN technology for accessing networks. Of these new devices, most of them are battery-operated and portable, and do not even have the capability to connect to wired Ethernet networks. As traffic shifts onto the wireless LAN, it must support new demands for connectivity. Increased numbers of devices is only the first part of a one-two punch being delivered by users. After connecting so many devices to wireless LANs, users then change the type of applications in use. With improved computing power and display technology, the user experience is becoming significantly more media-heavy, with a special emphasis on streaming multimedia and especially video support. Combine an increase in the number of devices with increased demand for capacity from each device, and you have a recipe for congestion unless greater capacity is in the cards. As the improved performance of 802.11ac becomes readily available in client devices, there will be user demand to take advantage of that speed.
Adoption of 802.11ac will likely happen more quickly than that of its predecessors. Improving speed is always welcome in networking, and many networks are built with a three- to five-year time horizon of service. Part of the planning process in building an 802.11ac network is to assess not only the current load on your network, but also the expected growth in demand for service to determine whether the increased density justifies using the highest-performance technology available. A strong industry focus on interoperability has made the transition to 802.11ac straightforward for network administrators as well.
Getting Ready for 802.11ac
802.11ac is evolutionary as much as it is revolutionary. Many of the design principles that have been used with previous technologies are still applicable, with a few minor changes to take advantage of new protocol features. The drivers to use 802.11ac are the same drivers that have justified every other network upgrade you have ever done:
- Peak speed and/or throughput
- The most obvious driver for 802.11ac is the new higher speeds. Some applications require as much speed as the network can deliver, and these are obvious beneficiaries of the new technology. Increased use of video is a major driver of 802.11ac adoption, as is the increase in device density due to the widespread use of tablets and wireless LAN–equipped smartphones. Video is widely used throughout the spectrum of wireless LAN users, whether it is large and detailed images for patient care, instructional videos in the classroom, or wireless display technologies in corporate conference rooms. Higher speeds also enable additional point-to-point deployment scenarios and provide the capacity necessary to serve 802.11n clients with mesh backhaul connections.
- Capacity
- With so much raw capacity, especially with wider channels, 802.11ac pr