What are the links and differences between URL, domain name, web address, and ip address?
There are millions of hosts on the Internet. In order to distinguish these hosts, people assign a special "address" to each host as an identifier, called an IP address, which is like you Online ID card, to check your own IP address, click "Start" → "Run" in the Windows 9x system → type "winipcfg" (2000/xp input ipconfig) → press Enter.
IP is
the abbreviation of Internet Protocol. To transfer information between each host, it is necessary to know the IP address of the other party. The length of each IP address is 32 bits (bit), divided into 4 segments, each segment is 8 bits (1 byte), usually expressed in decimal numbers, the range of each segment is 1 to 254, and the segments are separated by a decimal point. . Each byte (segment) can also be expressed in hexadecimal or binary. Each IP address includes two IDs (identification codes), namely the network ID and the host ID. All hosts on the same physical network use the same network ID, and a host (workstation, server, router, etc.) on the network has a corresponding host ID. In this way, the 4 bytes of the IP address are divided into 2 parts, one part is used to indicate the specific network segment, that is, the network ID; the other part is used to indicate the specific node, that is, the host ID. Such 32-bit addresses are divided into five categories, corresponding to IP addresses of type A, B, C, D, and E respectively.
Because IP addresses are all numbers, in order to facilitate users to remember, the Internet has introduced the domain name service system DNS (Domain Name
System). The traditional domain name and website address are technical matters and have strict regulations. The part constitutes a complete "URL" (URL). When you type a domain name, this information first reaches the server that provides the domain name resolution, and then resolves the domain name to the IP address of the corresponding website. The process of accomplishing this task is called domain name resolution. The process of domain name resolution is: when a machine a sends a domain name resolution request to its domain name server A, if A can resolve it, it will send the resolution result to a, otherwise, A will send a resolution request to its superior domain name server B, if B can resolve, then the analysis result is sent to a, if B cannot resolve, then the request is sent to the higher-level domain name server C... and so on, until the resolution is complete. The domain name is simply the name of the host on the Internet. It adopts a hierarchical structure. Each layer constitutes a subdomain. The subdomains are separated by dots. From left to right, they are: computer name, network name, organization name, The highest domain name. The Internet domain name system is a tree structure.
Routing (network engineering term)
Routing refers to the process of determining the network scope of the end-to-end path when a packet travels from the source to the destination. Routing works at the third layer of the OSI reference model-the packet forwarding device at the network layer. The router realizes network interconnection by forwarding data packets. Although routers can support multiple protocols (such as TCP/IP, IPX/SPX, AppleTalk, etc.), most routers in my country run TCP/IP. Routers usually connect two or more logical ports identified by IP subnets or point-to-point protocols, and have at least one physical port. The router determines the output port and next hop address according to the network layer address in the received data packet and the routing table maintained inside the router, and rewrites the link layer data packet header to forward the data packet. The router reflects the current network topology by dynamically maintaining the routing table, and maintains the routing table by exchanging routing and link information with other routers on the network.