This invention relates to an apparatus and method for reducing the transmission of data on a data communications network by obtaining data from a cache rather than by transmitting the data. This method maintains an indexed cache of data from previous transmissions. Then, when duplicate information is...http://www.google.com.hk/patents/US5377329?utm_source=gb-gplus-share專利 US5377329 - Reducing data transmission by indexed caching
