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The demands for anywhere-access and the rollout of higher-speed Wi-Fi standards have prompted enterprises to explore the feasibility of transitioning from a wired infrastructure to an all-wireless internal network. This chapter examines the challenges facing enterprise IT as it considers the possibilities of a wireless enterprise, moving more of the company's core operations to high-speed wireless LANs (WLANs). It also examines technologies required for true enterprise-scale wireless access.
Challenges facing would-be wireless enterprises
Today’s typical enterprise network administrator faces many challenges, but among the most taxing are those stemming from a bandwidth-hungry user base equipped with an ever-growing number of network-accessible devices. BYOD is the norm in many environments and, as a result, enterprises must now deliver a wide variety of applications -- from spreadsheets to video streaming -- to mobile users. Moreover, these users need reliable access to these services 24/7.
To become a wireless enterprise and transition to Wi-Fi as the primary access for users, administrators and network architects must consider how they can meet the following objectives:
- Deliver highly available and secure wireless access to employees and contractors on the internal network and access to guests and business associates in lobbies and conference rooms.
- Select appropriate tools and build an adequate infrastructure to support data, voice and video.
- Incorporate automated provisioning to deploy wireless technologies across the enterprise.
- Manage a wireless implementation using service-level and key-performance indicators, especially in support of mission-critical applications and services.
However, creating a wireless enterprise network and moving to all-wireless access is a much larger undertaking than simply upgrading wireless interfaces and access points (APs) to the latest and fastest standards. There’s quite a bit of underlying infrastructure to ponder, acquire and deploy as well.
Benefits of 802.11n and 802.11ac
Consider standards. Whereas 802.11n supports up to 600 Mbps, theoretically, with a channel width of 40 MHz, the relatively new 802.11.ac Wave 2 specification (also called the 802.11ac-2013 update) provides up to 7 Gbps of throughput in the 5 GHz spectrum. It doubles the channel width to 80 MHz, provides multiple input multiple output (MIMO) technology and offers beamforming for better interoperability, and it can prioritize latency-sensitive traffic. All of this adds up to significant benefits for 802.11ac deployments and makes all-wireless connectivity a more realistic option for enterprises. In particular, 802.11ac provides:
- Less interference: The 5 GHz band is less crowded than the 2.4 GHz band used in 80211.n, which means user devices are less susceptible to interference from other clients and devices.
- More bandwidth and air time: The 80 MHz channel width has more bandwidth, and faster speeds enable users to get on and off the network more quickly, making more air time available to other users.
- Support for more users: Multiple-user MIMO significantly increases the number of users the network can handle. Each AP divides available spatial streams, essentially quadrupling user density.
- Support for voice and video: 802.11ac is well-suited to supporting streaming audio and video.
Although many small to medium-sized environments have embraced 802.11ac, mainly due to the boost in capacity and capabilities, enterprises are taking a more cautious approach -- for good reason.
Enterprise administrators should approach a wireless implementation with thorough planning.
Although 802.11ac is backward-compatible with 802.11n, 802.11a and 802.11b, a network with mixed client technologies can slow down 802.11ac clients in particular. For that reason, many enterprises are looking to transition to a more complete wireless infrastructure that upgrades all APs and wireless interfaces at the same time.
Enterprise-grade APs should be fully compatible with the latest standard and be controller-based for easier configuration and management. They should also intelligently direct wireless clients to the nearest AP with the strongest signal and be able to analyze and select the best channel width, based on changing network conditions, all without having an effect on the user experience.
Deployment and management tools also play an important role in a successful transition to Wi-Fi. Enterprise tools must be robust, highly accessible (Web- or cloud-based) and integrated. They should provide auto-provisioning to set up WLAN zones across the network, eliminating the need for manual configuration. With an expected uptick in the number of users and devices, management tools must allow administrators to allocate percentages of airtime to different types of users or devices for quality of service purposes.
Fortifying the wired infrastructure
Higher data rates for 802.11ac may require the core wired infrastructure to be beefed up as well. Network architects and administrators need to look at emerging Ethernet standards, such as 802.3by (25 GbE) and 802.3bz (2.5G/5GBASE-T), when planning for 802.11ac implementations.
The 802.3by project aims to standardize backplanes, twinaxial cabling and multimode optical fiber. The 802.3bz effort will define standards for 2.5 GbE and 5 GbE for 100-meter Cat5e and Cat6 UTP cabling to overcome limitations of APs where 1G (1000BASE-T) cannot support 802.11ac data rates and where the existing 10GBASE-T standard cannot support a 100-meter reach using Cat5e cabling.
Has the day of the wireless enterprise dawned?
The higher speeds and capacities offered by current and emerging Wi-Fi standards promise better WLAN performance, suitable for enterprise use. The requirements to support a high-speed WLAN are, however, somewhat more complicated. It takes more skill and planning to successfully implement these new networks and to maintain and manage all their moving parts.
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