The computer network to learn well, first of all to put a seven-layer OSI network model it
Under the control protocol of the upper to lower call the lower to the upper layer service, with the exchange between the upper and lower primitive exchange information. This can increase the transmission rate, and ensure data security, so that in fact each layer has longer necessary
But now we have the Internet TCP / IP protocol, can be said to be some kind of black, he encapsulates the three former
Each floor also has a different protocol
During network communication, the host will send data is called a source host, the received data is referred to as the destination host. When the source host sends out the data, the data is transmitted to a lower layer from an upper layer in the source host. Source host application process in the first data to the application layer, the application layer with the necessary control information became packet flow, down to the transport layer. The transport layer data units received information together with the present control layer, forming segment, datagram, and then to the Internet layer. Internet layer control information together with the current layer, form an IP datagram passed to the network interface layer. The Internet layer network interface layer down cross-assembled IP datagram framing, and in the form of a bit stream transmitted to the network hardware (i.e., physical layer), leaving the source data to the host.
Transmitted through the network, the data reaches the destination host to the source host in accordance with the reverse process unpacks transmitted to the upper layer from the lower layer in the destination host. First, the data received by the network interface layer, successively peeled off together with the original control information. Finally, the application process the data in the transmission source host of the application process to the destination host.
The basic transmission unit TCP / IP protocol datagrams (Datagram), TCP protocol is responsible for dividing the data into several packets and add to each data packet header, a head of a serial number, to ensure that the data can be reduced to the destination host the original format. IP protocol on the receiving end of each packet headers plus a host IP address, so that data can find their own place to go. If the distortion data, data loss occurs during transmission, TCP protocol will automatically request retransmission of the data, and reorganization of the datagram. It can be said, to ensure that data transmission IP protocol, TCP protocol to ensure the quality of data transmission.
TCP / IP protocol in data transmission in each layer will add a header to the data by which the data receiving terminal for use with one protocol, at the receiving end, after each layer should remove the used header, so We can ensure the consistency of data transmission.
RPC（Remote Procedure Call）—远程过程调用，它是一种通过网络从远程计算机程序上请求服务，而不需要了解底层网络技术的协议。RPC协议假定某些传输协议的存在，如TCP或UDP，为通信程序之间携带信息数据。在OSI网络通信模型中，RPC跨越了传输层和应用层。RPC使得开发包括网络分布式多程序在内的应用程序更加容易。