7.4.1–7.4.3: When planning a WLAN, consider the following factors:
• Coverage areas: 802.11b/g/n have a larger coverage area than 802.11a.
• Existing implementations: 802.11n generally is backward-compatible with 802.11a/b/g, but some access points (AP) do not support the 5-GHz frequency and are not backward-compatible with 802.11a. A preexisting 802.11a installation may require all new equipment to support the same standard if your new APs do not support the 5-GHz frequency.
• Bandwidth requirements: All users share bandwidth on a BSS. The number of simultaneous users and type of applications in use can dictate the need for higher-speed equipment.
• Cost: Consider the total cost of ownership (TCO), including the equipment, ...