A guard interval is a period of time between transmissions that allows reflections from the previous data transmission to settle before an AP transmits data again. An AP identifies any signal content received inside this interval as unwanted inter-symbol interference, and rejects that data. The 802.11n standard specifies two guard intervals: 400ns (short) and 800ns (long). Enabling a short guard interval can decrease network overhead by reducing unnecessary idle time on each AP. Some outdoor deployments, may, however require a longer guard interval. If the short guard interval does not allow enough time for reflections to settle in your mesh deployment, inter-symbol interference values may increase and degrade throughput. Further to this below are the key points to remember about guard interval - For digital signals, data is modulated onto the carrier signal in bits or collection of bits called symbols. The guard interval is a period of time between symbols that accommodate for the la
http://www.ebrahma.com/2013/09/aruba-networks-default-guard-interval/Labels: eBrahma