From the November 2012 Issue of Cabling Installation & Maintenance Magazine
Study reviewed within IEEE says WiFi connections will barely edge out fixed-wired connections in 2015. But more importantly, all technologies are seeing significant increases in use.
By Scott D. Thompson, Oberon Inc.
The Institute of Electrical and Electronics Engineers (IEEE; www.ieee.org), developer of the 802.3 standard, engaged the IEEE 802.3 Higher Speed Study Group (HSSG) to chart a path for higher networking speeds. Of course, this is of great interest to the structured cabling community, as the adoption of higher-speed standards will impact data communications cabling (copper and fiber), network and storage interface electronics, wireless interfaces, applications developers, and the entire installation community. It was observed by the group that core networking speed and computing application speeds are growing very rapidly and at different rates, thereby driving the need to develop new wireline Ethernet standards and speeds. Because of the contention between cost, distance and speed priorities for different technologies, networks and applications, the IEEE P802.3ba Task Force developed two rate objectives for the new 802.3ba Ethernet standard-40 Gigabit Ethernet and 100 Gigabit Ethernet.
In order to effectively understand the 802.3ba 40-Gigabit and 100-Gigabit Ethernet requirements, the IEEE 802.3 Ethernet Bandwidth Assessment Ad Hoc was created. The scope of this ad hoc was to focus on gathering information that would enable an assessment of the bandwidth needs for Ethernet wireline applications, including, but not limited to, core networking and computing. The bandwidth associated with core networking was observed, on average, to be doubling every 18 months. On the other hand, the bandwidth capability associated with high-volume x86 servers and computing applications, fueled by Moore's Law, was doubling every 24 months. The Ad Hoc gathered information from 11 industry-leading source presentations, looking at a variety of application spaces including servers, data center networks, high-performance computing, financial markets, carrier and cable operators, Internet exchanges, and the scientific community. The Assessment Ad Hoc recently completed a year-long effort and released a report providing an updated view of industry bandwidth trends impacting Ethernet wireline applications.
This assessment is about the future bandwidth needs of Ethernet wireline applications. However, to be comprehensive, it does include information on access interconnect technology projections, including mobile data (cell phones), WiFi (wireless LAN), and fixed wireline. Based on one of the study's sources (Nowell, M. Cisco Visual Networking index [VNI] Global IP Traffic Forecast Update; 2010-2015), mobile data will experience a 92-percent compound annual growth rate (CAGR) between 2010 and 2015, but still only account for 7.8 percent of the overall traffic in 2015. Fixed/wired will experience a 24-percent CAGR during the same period, and account for 46.1 percent of the overall traffic in 2015. Finally, fixed/WiFi will experience a 39-percent CAGR over this period, and account for 46.2 percent of all traffic. The graph summarizes the global IP traffic by local access technology forecast.
The reality behind the numbers
These growth numbers are highly plausible, as growth in these access technologies has been on this trajectory for years. By 2015, WiFi is the leading access interconnect for client devices (albeit by 0.1 percent), but the important takeaway from this is that all interconnect technologies are growing rapidly, and facilities will need the infrastructure for all three technologies. This means additional, more readily available high-speed wireline connections; a robust, full-bandwidth WiFi installation; and available cellular connections throughout the facility, augmented with an in-building wireless distributed antenna system (DAS). Of course, WiFi and DAS entail additional high-speed structured cabling.
This 39-percent CAGR for WiFi access interconnect is a multiplying factor of 5.2x over 5 years. To map this growth into an existing WiFi network, a network that supported an 802.11a/g network with 25-Mbit/sec MAC layer data throughput to each access point in 2010 should support 130-Mbit/sec MAC layer data throughput in 2015 (i.e. Gigabit Ethernet to each access point). An IEEE 802.11n wireless network designed for 100-Mbit/sec MAC layer data throughput to each access point will need to grow to support 520-Mbit/sec MAC layer data throughput in 2015.
Growth in WiFi access speeds will be enabled by the new draft IEEE 802.11ac "Gigabit WiFi" wireless standard, which promotes 1-Gbit and greater data throughput. Commercial-grade 802.11ac products will be available in 2013, and will subsequently drive this uptick in wireless bandwidth. IEEE 802.11ac engages the full 5-GHz band (but not the crowded 2.4-GHz band), beamforming, and additional spatial streams to improve data throughput.
Mobile-data growing pains
The 92-percent CAGR in mobile-data (cellular) use implies a multiplying factor of 26x over 5 years, which will be problematic. There is a scarcity of bandwidth to provide these data services in many urban areas already. The mobile carriers will use new bandwidth and advanced modulation and coding (4G) to add capacity. But this is not the total solution. The solution will include, in part, both network offloading and spectrum reuse. Network offloading is the process whereby a device, say a smartphone or iPad, prefers to connect to the private wireless LAN when available, versus the public cellular data network. This can help free up scarcer cellular bandwidth.
Spectrum reuse is the method of using small, low-power cells, such that the same piece of spectrum can be reused within a geographical area. This is manifested as in-building wireless DAS. With DAS, a miniature cellular infrastructure is deployed inside the building, using low-power "access units" rather than full-power base stations. The coverage area is scaled down to cover just inside the building, or a portion of the building. This allows the same spectrum to be reused outside the building, or in another nearby building. Spectrum reuse will greatly increase the total capacity of a cellular network, but now the cellular infrastructure is not just outside-plant and backhaul designed and owned by the cellular carrier. Spectrum reuse will use in-building wireless DAS and require cooperation of carriers, building owners, manufacturers, designers, integrators and installers for intelligent spectrum and network resource utilization.
Network designers, integrators and installers need to become more-well-versed in all three of these interconnect technologies as no single technology replaces another. Rather, the speed, capability and availability of all three access technologies will continue to increase at a very brisk rate.
The IEEE 802.3 Ethernet Working Group's Industry Connections Ethernet Bandwidth Assessment report can be viewed at: ieee802.org/3/ad_hoc/bwa/BWA_Report.pdf.
Scott D. Thompson is president of Oberon Inc. (oberonwireless.com).