See the next Ruan a peak of the "Internet Protocol Primer" article, feel well written, after reading, wrote a book outline.
Link Layer0/1 signal transmission via wired/wireless mode.
Link LayerEthernet protocol: A group of signals constitute a packet called "frame", including the header (head) and data (the header), including the sending/receiving side of the MAC address, data type, the data portion of the maximum 1500 bytes, more than the post-split send, the sender through the ARP protocol to obtain the receiver's MAC address The sender sends data to and from the sub-network in a broadcast manner. Get the other side of the Mac way: The two sides are located in different sub-networks, unable to get through the Subnet gateway processing, located in the same subnet (ARP protocol), to broadcast the other side of the IP, the other side after acquiring data, the MAC address is returned. The same sub-network communication, need the other side's MAC address and IP address, different sub-network communication, need to send the network Gateway MAC address and the other side's IP address.
Network LayerSolve the problem of Ethernet broadcast, establish host-to-host communication. IP protocol: Locate the receiver's sub-network through the network address, the IP sub-network part and the host part, the network part determines the sub-network, the subnet mask and the IP do and operation can determine the different IP in a sub-network, the IP packet sub-header and the data part, the total length of not more than 65535 bytes, The data portion of the Ethernet packet is transferred, the IP address can be specified manually, or it can be obtained through the DHCP protocol;
Transport LayerPort-to-port communication is established by receiving the data, using ports to differentiate between different types. Network development via sockets (socket: Host + port). UDP protocol: The sub-header and Data section, the header contains port information on both ends of the communication, the total length of not more than 65535 bytes, placed in the data portion of the IP packet transmission. TCP protocol: Through three handshake, to solve the UDP protocol reliability problem, the theoretical length is not limited, but preferably not more than 65535bytes to avoid a split transfer of TCP packets.
Application LayerSpecifies the data format of the application, such as Http,ftp,email. The DHCP protocol is a UDP-based application-layer protocol that obtains information such as IP address, subnet mask, gateway address, DNS server, and so on, from the DHCP server by means of broadcast. The DNS protocol is also a UDP-based application-layer protocol that translates URLs into IP addresses.
Basic knowledge Outline of network protocol
