Defining the WLAN Requirements
When designing any network, the first step is to determine user needs. For a WLAN, this includes defining the coverage area. Before you can determine what you need, you have to decide why you need it. Mobility is most often the reason for implementing a wireless network, although mobility should not be confused with providing uninterrupted connectivity with the LAN. So, early in the planning stage, you must determine the key points at which users will reside, as well as the most common paths between the primary gathering locations, such as conference rooms, the offices of key personnel, development labs, and so forth. Critical to this process is a good diagram of the facility showing what the WLAN needs to cover.You also need to determine the minimum speeds users require. Toward this end, you must have a description of the applications that the users run. Of course, every network engineer will say that each user needs 100 Mbps, just as in a wired switched network. However, wireless is not a switched medium. It is a shared medium. Therefore, not all applications will truly fit well into a WLAN system. Based on most networks analyzed, network use is in fact very "peaky"a user requests a download (low speed required), followed by the actual download (greater speed required). The opposite can be true when uploading documents. Because traffic loads tend to vary to a great extent, most network designs require a fraction of the available bandwidth thought of as mission critical. This does not mean that high-speed networks of 100 Mbps and even gigabit rates are never needed; after all, the minimum amount of speed required generally increases over time as more users access a LAN.It is unlikely that all users in a LAN will use the same client device. Therefore, you need to determine whether users need specialty devices on the wireless system, such as bar code readers, PCI cards, PCMCIA cards, wireless IP phones, or perhaps even wireless print servers. If so, you need to decide whether it is possible to procure all the end devices from the same vendor or whether there will be different-vendor products in the mix. This decision could be very important because of some vendor-interoperability issues with proprietary features. |
لطفا منتظر باشید ...
