An aircraft constructed with a tractor configuration has the engine mounted with the airscrew in front of it so that the aircraft is "pulled" through the air
【简答题】点对点协议用在因特网的数据链路层。它有三个性质 :成帧方法、链路控制协议以及网络控制协议。 The protocol (PPP) is used in the data link layer of the . It has three features: a method, a control protocol (LCP), and Control Protocol (NCP).