Design of Network Data Transmission Mixed Model Based on Hypothesis Model and Threat Model
Jianying Wang · 2017
The data communication network is a system composed of data terminals, data transmission equipment, digital exchange equipment and digital communication lines distributed everywhere.The contents of the communication are binary coded letters, numbers, symbols, and digitized sound and image information.The data communication network and the computer combine to form a computer network, which can use the computer connected to the network and communicate with any other users in the network. Analysis of Data Transmission in NetworkWe are using the Internet every day, how is the data on our computer through the Internet to another computer?Write your own understanding, there may be a lot of details cannot be very clear!Hope in the future can make it more perfect!There are wrong places also please correct me.We know that the TCP / IP protocol used in today's Internet is based on the seven-layer reference model of the OSI (open system interconnection), although not fully compliant, from top to bottom, respectively, for the application layer presentation layer session layer Transport layer network layer Data link layer and physical layer.The data link layer is divided into two sub-layers, namely, logical link control (LLC) and media access control (MAC), which is usually the MAC layer.The nodes in the node are initialized to prevent the connection from being interrupted and maintain reliable communication.The .MAC layer is used to verify the address information contained in each frame.The following will be analyzed.Also understand that the router is at the network layer while the NIC is in the data link layer.We know that ARP (Address Resolution Protocol) is used as the underlying protocol for IP address to physical address conversion.In the Ethernet, all access to the IP eventually converted to access to the MAC address of the network card.If the host A's ARP list, to the host B's IP address and MAC address corresponds to the incorrect, sent by the A packet to the B packet will be sent to the wrong MAC address, of course, cannot successfully reach B, the result is A and B simply cannot to communicate.First of all, we analyze the situation in the same network segment.Assuming that two computers are named A and B, respectively, A need to send data to phase B, A host first the target device B's IP address and its own subnet mask "and" operation to determine whether the target device with their own Located in the same network segment.If the target device is in the same network segment and A does not obtain the MAC address information corresponding to the IP address of the target device B, the source device (A) sends ARP in the form of the second layer broadcast (the destination MAC address is all 1) Request packet, which contains the IP address of the source device (A) and the target device (B) in the ARP request packet.All the other devices in the same network segment can receive and analyze the ARP request packet.If the destination IP address of a device discovery packet is the same as its own IP address, it sends an ARP response packet to the source device, the source device obtains the MAC address information of the target device.In order to reduce the broadcast volume, the network device through the ARP table in the cache to save IP and MAC address mapping information.In the process of ARP request and response, both sides of the communication of each other's MAC address and IP address of the correspondence relationship in the respective ARP table to use in the subsequent communication.The ARP table uses the aging mechanism to remove the mapping between IP and MAC addresses that have not been used for a period of time.