users will typically require concurrent service? How much future growth is the network expected to cater for? Continued Chapter Seven Table 7-1: WLAN User Requirement Types - cont'd Requirement type Considerations Security How confidential is the information transferred across the network? What level of protection is required against unauthorised access? Battery life If mobile devices will be used in the network, how often will the user need to recharge battery operated devices? Economic What budget is available to implement the WLAN? Are there specific requirements that deliver high value and may justify higher cost solution? Table 7-2: WLAN Technical Attributes Requirement type Considerations Effective data rate The required data rate for a single user will be dictated by the usage model, for example by the typical file size and upload/download time, or by the requirements for voice or video streaming. As discussed in Chapter 6, effective data rates can be significantly lower than a standard PHY layer data rate, and will be further affected by adverse environmental factors such as RF interference. Network capacity What is the overall network capacity needed to provide the required level of service, given the current and future expected size of the user group and number of user devices? Required capacity will be a key factor both in the technology selection and in determining the appropriate physical architecture for the WLAN. Quality of service If the usage model includes applications such as VoWLAN, then guaranteed quality of service will be an important attribute to ensure performance expectations are met. Application support Are there specific technical attributes required to support particular usage models? Network topology What types of connections are required to meet user requirements? For example, peer-to-peer for local data sharing, point-to-point for linking buildings, etc. Security If users' confidentiality requirements are high, then data encryption, network access monitoring and other security meas