它的关键特性是一个非常快的算法，它只通过数据链路发送文件差异，因此把机器之间传输的数据总量降低到最低限度。
Its key feature is a very fast algorithm that just sends file differences over the data link, thus minimizing the total data flow between machines.
捐助人可以在电子数据表上监看供应的进展，并可相互发送短消息：这条路受到盗匪的袭击，那个村庄被洪水切断了与外界的联系。
Donors keep track of supplies on spreadsheets and send each other SMS messages: this road has been attacked by bandits, that village cut off by floods.
IP位于下一层，在OSI的网络层，即第三层，把每个包的发送者和接收者地址告诉一路上各个路由器。
IP, located one layer down, at the OSI network layer, or layer 3, communicates the addresses of each packet's sender and receiver to the routers along the way.
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