How does IP realize network interconnection? Network systems and devices produced by different manufacturers (such as Ethernet and packet-switched networks) cannot communicate with each other. The main reason why they can't communicate with each other is that the formats of the basic units (technically called "frames") of the data they transmit are different. IP protocol is actually a set of protocol software composed of software programs, which converts various "frames" into "IP packets" format. This transformation is one of the most important features of the Internet, which enables all kinds of computers to communicate with each other on the Internet, that is, it has the characteristics of "openness". So, what is a "data packet"? What are its characteristics? Data packet is also a form of packet switching, that is, the transmitted data is divided into "packets" before transmission. However, unlike the traditional "connected" packet switching, it belongs to the "connectionless" type and sends each typed "packet" as an "independent message", so it is called "data packet". In this way, there is no need to connect the circuit before starting communication, and all data packets may not be transmitted through the same path, so it is called "connectionless". This feature is very important, which greatly improves the robustness and security of the network. Every packet has two parts: a header and a message. The header contains necessary contents, such as the destination address, so that each packet can reach the destination accurately without going through the same path. Recombined and restored to the original data at the destination. This requires IP to have the function of package encapsulation and assembly. In the actual transmission process, the length of the packet can also be changed according to the packet size specified by the delivery network, and the maximum length of the IP packet can reach 65,535 bytes. Another important content in the IP protocol is to provide every computer and other equipment on the Internet with a unique address called "IP address". Because of this unique address, when users operate on networked computers, they can effectively and conveniently select the objects they want from thousands of computers in Qian Qian. Nowadays, telecommunication network is merging with IP network, and new technologies based on IP are popular technologies, such as VoIP, and other technologies, such as IP over ATM, IPover SDH, IP over WDM, etc. , is the research hotspot of IP technology.
[Edit this paragraph ]IPV4 address
The so-called IP address is a 32-bit address assigned to each host connected to the Internet. According to TCP/IP (Transmission Control Protocol/Internet Protocol) protocol, IP addresses are expressed in binary, and each IP address is 32 bits long, which is 4 bytes when converted into bytes. For example, a binary IP address is "000010100000000000001",which is too long for people to handle. In order to facilitate people's use, IP addresses are often written in decimal form, with the symbol "."separating different bytes in the middle. Therefore, the above IP address can be expressed as "10.0.0. 1". This representation of IP address is called dotted decimal representation, which is obviously much better to remember than 1 and 0. Some people think that a computer can only have one IP address, which is wrong. We can specify that a computer has multiple IP addresses, so when accessing the Internet, don't think that an IP address is a computer. In addition, through specific technology, multiple servers can use one IP address, and these servers look like a host to users. When an IP address is divided into two parts: the network number and the host number, the designer must decide how many bits each part contains. The number of digits of the network number directly determines the number of networks that can be allocated (calculation method 2: Number of digits of the network number); The number of digits of the host number determines the maximum number of hosts in the network (calculation method 2 host number digits -2). However, because the network scale contained in the whole Internet may be relatively large or relatively small, the designer finally chose a flexible scheme: dividing the IP address space into different categories, and each category has a different network number and host number. IP address is the basis of data transmission in IP network. It identifies a connection in an IP network, and a host can have multiple IP addresses. The IP address in the IP packet remains unchanged in the network transmission. (1) Basic address format (IPv4) The current IP network uses 32-bit addresses, which are expressed in dotted decimal system, such as192.168.0.1. Address format: IP address = network address+host address or IP address = network address+subnet address+host address. Network addresses are assigned by ICANN (Internet Corporation for Assigned Names and Numbers) of the Internet Society. InterNIC is responsible for North America, RIPENIC is responsible for Europe, and APNIC is responsible for Asia-Pacific, in order to ensure the global uniqueness of network addresses. The host address is assigned by the system administrator of each network. Therefore, the uniqueness of network address and the uniqueness of host address in the network ensure the global uniqueness of IP address. (II) Allocation of reserved addresses According to different purposes and security levels, IP addresses can be roughly divided into two categories: public addresses and private addresses. Public addresses are used on the Internet and can be accessed at will. Private addresses can only be used in internal networks, and only through proxy servers can they communicate with the Internet.
ip address inquiries
Start-Run, enter cmd-enter ipconfig/all in the pop-up dialog box, and then press enter to appear a list, one of which is: ip address is ip address.
Classification of IP addresses
Network number: used to identify the network where the host is located; Host number: used to identify the host in this network. IP addresses are divided into five categories: A reserved for government agencies, B allocated to medium-sized companies, C allocated to anyone who needs it, D used for multicast, and E used for experiments. The number of addresses that can be accommodated in each category is different. Characteristics of class A, B and C IP addresses: When IP addresses are written in binary form, the first digit of class A address is always 0, the first two digits of class B address are always 10, and the first three digits of class C address are always 1 10. 1. Class A address (1) Class A address1byte is the network address, and the other three bytes are the host address. (2) Class A address range:1.0.126.255.254 (3) Private address and reserved address in Class A address: ① 10. X.X.X is a private address. The range (10.0.0-10.255.255.255) ②127.x.x is a reserved address for loop testing. 2. Class B address (1) The1byte and the second byte of Class B address are the network address, and the other two bytes are the host address. (2) Class B address range:128.0.1-191.255.254. (3) The private address and reserved address ①172.16.0.0-172.31.255.255 are private addresses ②169.254.x is reserved. If your IP address is automatically obtained and you can't find an available DHCP server on the network. You will get an IP. 3. Class C address (1) The1byte, the second byte and the third byte of Class C address are network addresses, and the fourth byte is the host address. In addition, the first three bits of the byte 1 are fixed as 1 10. (2) Class C address range:192.0.0.1-223.255.255.254. (3) Private address of Class C address: 192. 168. X.X is a private address. (1 92.168.0.0-192.168.255.255) Class D addresses (1) Class D addresses do not distinguish between network addresses and host addresses, and they1. (2) Class D address range: 224.0.01-239.255.254 5. Class E address (1) Class E addresses do not distinguish between network addresses and host addresses, and the first five bits of its1byte are fixed at 65438+. (2) Class E address range: 240.0.01-255.255.254 IP has a wide range of concepts, including brands, trademarks, copyrights, and most importantly, trade secrets, business models and business standards. The amount of intellectual property ownership is the most important symbol to distinguish manufacturing from creation. If a country has too little IP, its industry or enterprise can only play the role of primary processor in the international division of labor.
Special IP address
In the IP address space, some IP addresses cannot be assigned to devices, some IP addresses cannot be used for public networks, and some IP addresses can only be used for this machine. There are also many such special IP addresses: multicast addresses, and pay attention to the difference between them and broadcasting. The addresses from 224.0.0.0 to 239.255.255.255 are all like this. 224.0.0. 1 means all hosts, and 224.0.0.2 means all routers. This address is mainly used for some specific programs and multimedia programs. If your host has turned on the IRDP (Internet Routing Discovery Protocol) function, there should be such a route in your host routing table. 169.254.x.x If your host uses the DHCP function to automatically obtain an IP address, then when your DHCP server fails, or the response time is too long, which exceeds the time specified by a certain system, the Windows system will assign you such an address. If you find that your host IP address is such an address, unfortunately, nine times out of ten, your network is not working properly. Limited broadcast address broadcast communication is a one-to-many communication mode. If the binary digits of an IP address are all 1, that is, 255.255.255.255, then this address is used to define the whole Internet. If the device wants IP datagrams to be received by the whole Internet, it will send a broadcast packet with the destination address of 1, but this will bring a disastrous burden to the whole Internet. Therefore, all routers on the network will prevent this type of packet from being forwarded, thus limiting this kind of broadcast to the local network segment. Direct broadcast address The last address in the network is a direct broadcast address, that is, an address with all HostID of 1. The host uses this address to send IP datagrams to all devices in the local network segment, and the router will forward the datagrams to all hosts in a specific network. Note: This address can only be used as the destination address in IP datagrams. In addition, direct broadcast addresses reduce the number of addresses that can be assigned to devices in a network segment by 1. The IP address is 0.0.0.0. If all IP addresses are 0, that is, 0.0.0, then this IP address can only be used as the source IP address in the IP datagram. This happens when the device is started but does not know its own IP address. This kind of address is very common in the network environment where DHCP is used to assign IP addresses. In order to obtain an available IP address, the user host sends an IP packet to the DHCP server, and takes this address as the source address and the destination address is 255.255.255.255 (because the host does not know the IP address of the DHCP server at this time). When a host sends a message to other hosts in the same network segment, it can use an IP address with a NetID of 0, and the router will not forward the packet. For example,12.12.12.0/24, one host in this network,12.2/24, another host in the same network,124. Loopback address 127 All addresses in the network segment are called loopback addresses, which are mainly used to test whether the network protocol works normally. For example, ping127.1.1can be used to test whether the local TCP/IP protocol is installed correctly. Another use is that when a client process sends a message with a loopback address to a server process located on the same machine, for example, by typing 127. 1.2.3 in the browser, it can be used to test whether IIS starts normally when network routing is excluded. Private Addresses In the IP address space, some IP addresses are defined as private addresses, which cannot be assigned to Internet network devices and can only be used within the enterprise, so they are also called private addresses. If you want to use such an address on the Internet, you must use network address translation or port mapping technology. These private addresses are: 10/8. The address range is: 10.0.0 to 10.255.255 * * There is a power of 2172.1612 Address range:172.
[Edit this paragraph] The development and characteristics of ]IPV6.
IPv6 is the abbreviation of "Internet Protocol Version 6", also known as the next generation Internet protocol. It is a new IP protocol designed by IETF (Internet Engineering Task Force) to replace the current IPv4 (current IP) protocol. As we know, all Internet hosts have a unique IP address, and the IP address represents a host number with a 32-bit binary number. However, 32-bit address resources are limited, which can no longer meet the needs of users. Therefore, Internet research institutions have released a new host identification method, namely IPv6. In RFC 1884 (RFC is the abbreviation of document for soliciting opinions. RFC is actually some standards of Internet service). The stipulated standard syntax suggests that the 128 bits (16 bytes) of IPv6 address should be written as 8 unsigned integers, with 16 bits, and each integer is represented by 4 hexadecimal bits, and these numbers are separated by colons (:). For example: 3ffe: 3201:1:1280: c8ff: fe4d: db39 IPv6 features: Extended addressing capability IPv6 extends the IP address length from 32 bits to128 bits, supporting more levels. By adding a "range" domain to the multicast address, the scalability of multicast routing is improved. A new address type called "anycast address" is also defined to send packets to any node in the group. Simplified header format Some IPv4 header fields have been deleted or become optional fields to reduce the consumption of routine processing in packet processing and limit the bandwidth consumed by IPv6 headers; The change of the encoding method of the improved IP header option supported by the extension header and the option can improve the forwarding efficiency, make the restriction of the option length more relaxed, and provide greater flexibility for introducing new options in the future; The ability to identify flows adds a new ability, which makes it possible to identify packets belonging to a specific communication "flow" that the sender needs special treatment (such as "real-time" services with non-default quality of service); Authentication and encryption functions IPv6 specifies extended functions to support authentication, data integrity and (optionally) data confidentiality.
[Edit this paragraph] Proxy IP
Proxy IP is Proxy Server, and English is proxy server. Its function is to obtain network information on behalf of network users. Figuratively speaking, it is a transit point for network information. Under normal circumstances, when we use a web browser to directly connect with other internet sites to obtain network information, we must send a request signal to get an answer, and then the other party will send back the information in the form of bit. A proxy server is a server between a browser and a Web server. With it, the browser does not go directly to the Web server to retrieve the web page, but sends a request to the proxy server. The request signal will be sent to the proxy server first, and the proxy server will retrieve the information needed by the browser and send it to your browser. Moreover, most proxy servers have the function of buffering, just like a big cache, which has a lot of storage space. It constantly stores the newly obtained data in its local memory. If the data requested by the browser already exists in its local storage and is up-to-date, the data will not be retrieved from the Web server, but will be directly transferred from the storage to the user's browser, which can significantly improve the browsing speed and efficiency. More importantly, proxy server is an important security function provided by Internet link-level gateway, and its work is mainly in the dialogue layer of OSI model. The main functions are: 1. Break through your own IP access restrictions and visit foreign websites. Network users such as Education Network and 169 Network can access foreign websites through agents. 2. Access to the internal resources of some units or groups, such as the FTP of a university (provided that the proxy address is within the allowed access range of resources), and use the free proxy server in the address section of the Education Network, which can be used for all kinds of FTP downloads and uploads open to the Education Network, as well as all kinds of information inquiry and service enjoyment. 3. Break through the IP blockade of China Telecom: Many websites of China Telecom users are restricted. This restriction is artificial, and different service block addresses are different. So when you cannot access it, you can try another foreign proxy server. 4. Improve access speed: Generally, the hard disk buffer of proxy server is relatively large. When external information passes, it is also stored in the buffer. When other users access the same information again, the information is directly taken from the buffer and passed to the users, which improves the access speed. 5. Hide the real IP: Internet surfers can also hide their IP in this way to avoid attacks.
[Edit this paragraph ]IP authentication
Intellectual property preservation certification is a process of reviewing and issuing certificates according to specific standards for the guarantee system established by enterprises to maintain the specific identity of products (such as genetically modified identity). In order to prevent the pollution of potential genetically modified ingredients in food, feed and seed production, IP system ensures the purity of "identity" of non-genetically modified products and improves the production and quality assurance system of product value through strict control, detection and establishment of traceable information in the whole production supply chain from non-genetically modified crop seed sowing to agricultural product field management, harvesting, transportation, export and processing. The characteristics of IP system are: (1) traceability, providing all-round information of the whole production supply chain for products; (2) Strictly isolate and eliminate accidental mixing of all uncontrolled materials; (3) strategic representative sampling and testing to verify the non-GMO labeling of products; (4) Perfect system documents and procedure manuals are the basis of product quality assurance; (5) Strict internal and external control. Ensure the effective operation of the intellectual property system. In addition, the world's largest paper and forest products enterprise: International Paper Industry (IP).
[Edit this paragraph] other meaning of IP
1. In electronic products, another meaning of IP (international protection) was drafted by IEC (International Electrotechnical Commission). Lamps and lanterns are classified according to their dustproof, foreign body intrusion-proof, waterproof and moisture-proof characteristics. The foreign objects mentioned here, including tools and people's fingers, must not touch the live parts in the lamps to avoid electric shock. The IP protection level consists of two numbers. The first number indicates the dustproof and foreign body intrusion prevention level of the lamp. The second number indicates the tightness of the lamp against moisture and water intrusion. The higher the number, the higher the protection level. Table 1 and Table 2 show the protection levels indicated by two tag numbers. The first mark feature number (#) refers to the degree of protection. The first mark number: 0 has no protection, and there is no special protection for people or things outside. IP0- 1 Prevent the intrusion of solid objects larger than 50mm, and prevent the human body (such as palm) from accidentally contacting the parts inside the lamp. Prevent foreign objects with larger size (diameter greater than 50mm) from invading IP 1- 2, prevent solid objects larger than 12mm from invading, and prevent people's fingers from touching parts in the lamp. Prevent medium-sized foreign objects (diameter greater than 12mm and length greater than 80mm) from invading IP2- 3, prevent solid objects larger than 2.5mm from invading, prevent tools, wires or similar small foreign objects with diameter or thickness greater than 2.5mm from invading and contacting the internal parts of IP3- 4, and prevent solid objects larger than 1.0mm from invading. Prevent tools, wires or similar small foreign objects with a diameter or thickness greater than 1.0mm from invading and contacting the internal parts of the lamp for dust prevention, so as to completely prevent foreign objects from invading. Although dust intrusion cannot be completely prevented, the amount of dust intrusion will not affect the normal operation of the lamp. The dust density of IP5- 6 can completely prevent foreign objects from invading, and it can completely prevent dust from invading. The protection degree indicated by the characteristic number (number) of the second mark of IP6- 0 is no protection, and there is no special protection for people or things other than IP-0 1 to prevent dripping water from invading. Vertical dripping (such as condensed water) will not have adverse effects on lamps. When the lamp inclines from vertical to 15, IP- 1 2 can still prevent dripping water from invading. When the lamp inclines from vertical to 15, dripping water will not have harmful effects on the lamp. IP-3 4 prevents splashing water from entering lamps and lanterns, IP-4 5 prevents water sprayed from all directions from entering lamps and lanterns and damaging them, and IP-5 6 prevents big waves from entering lamps and lanterns installed on deck. IP-6 7 prevents damage caused by flood caused by big wave invasion. IP-67 can prevent water from entering during flood. When the lamp is soaked in water for a certain time or the water pressure is lower than a certain standard, it can be guaranteed that the lamp will not be damaged by water ingress. IP-7 8 prevents water from entering when sinking. When the lamp sinks infinitely, IP-8 2 under the specified water pressure. IP stands for Ingress Protection. The first number, such as IP6_, stands for dust protection (6 stands for no dust entering, see the table below). The second number, such as IP_5, stands for waterproof protection (5 stands for the spraying of protective water, see the table below). The first digital definition describes the prevention of liquid intrusion–the second digital definition describes 0 unprotected. No special protection. 0 is not protected. No special protection. 1 Protect solid foreign bodies with a diameter of 50mm or more. Protect objects with large surface area, such as hands (against intentional intrusion). 1 protective water droplets (water droplets falling vertically) 2 Protect solid foreign bodies with a diameter of 12mm or more. Protect fingers or other objects with a length not exceeding 80 mm 2 When the equipment is tilted 15 degrees, it will prevent water droplets. Water drops falling vertically should not cause harm. 3 Protect solid foreign bodies with a diameter of 2.5 mm or more. Protective tools, metal wires, etc. Its diameter or thickness exceeds 2.5 mm .. 3 to protect the spilled water. Water splashing from both sides of the vertical line at an angle of 60 degrees should not cause damage. 4 Protect solid foreign bodies with a diameter of 1.0mm or more. Protect metal wire or metal strip with thickness greater than1.0 mm. 4 Protective water spraying. When the equipment tilts to the normal position of 15 degrees, water spraying aimed at the equipment from any direction should not cause damage. 5 dustproof. It is impossible to completely prevent dust from entering, but the amount of dust will not affect the normal operation of the equipment. 5. Protect the sprinkler. Spraying water on the equipment from any direction will not cause damage. 6 dustproof. No dust has entered. 6 prevent big waves. The amount of water that big waves or strong currents enter the equipment should not cause damage. 7 flood protection. When immersed in water under the specified pressure and time, there should be no water that will cause damage. 8 prevent flooding. Under the conditions specified by the manufacturer, the equipment can be immersed in water for a long time. The test method and main test conditions of water resistance test (IP_5) are defined as follows: test method-the nozzle has an inner diameter of 6.3mm and is placed at a distance of 2.5-3 m from the sample. Water flow–12.5 l/min 5% test duration–1min/m2, but at least 3 minutes. Test conditions–Spray test samples from every feasible angle. 3. In 8088 or 8086, IP (instruction pointer) refers to the instruction pointer register, which is a register inside the CPU to store the offset of the next instruction to be executed. Its value can be changed by JMP instruction, for example, using JMP AX to change IP with AX value, so as to realize the jump between segments. Intellectual property IP is the abbreviation of intellectual property, which means intellectual property. Intellectual property is an intangible property right, also known as intellectual achievement right, which refers to the achievements obtained through intellectual creative labor and is the exclusive right enjoyed by intellectual workers according to law. Such rights include personal rights and property rights, also known as moral rights and economic rights. The so-called personal right means that the right is inseparable from the person who has made intellectual achievements, and it is a legal reflection of personal relationship. For example, the author's right to sign the work, or the right to publish and modify the work, and so on. The so-called property right refers to the right that the obligee can use the intellectual labor achievement to get remuneration or reward after it is recognized by law. This right is also called economic right. The object of intellectual property protection is the creation of human mind and intelligence, the right of human intellectual achievements, and the right enjoyed by intellectual achievements created by all intellectual activities in science, technology, culture and art according to law. Intellectual property is a legal concept widely used in the world. Intellectual property rights include industrial property rights and copyrights (called copyrights in China). Industrial property rights include patents, trademarks, service marks, names of manufacturers, names of countries of origin and prevention of unfair competition. Copyright refers to the right of a unit or individual to print, publish and sell a work according to law. Anyone who wants to copy, translate, adapt or perform needs permission from the copyright owner, otherwise it will infringe on the rights of others. The essence of intellectual property rights is to treat human intellectual achievements as property. Trademark right refers to the exclusive right given by national laws to trademark owners to protect their registered trademarks. A trademark is a commercial symbol used to distinguish goods and services from different sources. It consists of words, graphics, letters, numbers, three-dimensional symbols, color combinations or combinations of the above elements. The acquisition of trademark rights in China must fulfill the trademark registration procedure and implement the principle of first application. Copyright is the creator and creator of literary, artistic and scientific works, and it is a civil right enjoyed by their works according to law. Patent right and patent protection refer to the patent application filed with the State Patent Office, and after passing the examination according to law, the patent applicant is granted the exclusive right to enjoy the invention and creation within a specified time. After an invention-creation is granted a patent right, the patentee enjoys exclusive rights to his invention-creation. No unit or individual may exploit its patent without the permission of the patentee, that is, it may not manufacture, use, promise to sell, sell or import its patented products for production and business purposes. Without the permission of the patentee, the implementation of his patent will infringe his patent right and cause disputes, which shall be settled by the parties through consultation; Unwilling to negotiate or if negotiation fails, the patentee or interested party may bring a lawsuit to the people's court or request the administrative department for patent affairs to handle it. Patent protection adopts the protection mode of "two-way parallel and judicial guarantee" between judicial and administrative law enforcement. The administrative protection in this area takes the form of patrol law enforcement and joint law enforcement, focusing on cracking down on group infringement, repeated infringement and other phenomena that seriously disturb the patent legal environment. Three characteristics of intellectual property: 1, exclusiveness of intellectual property, that is, exclusivity or monopoly; 2. The regionality of intellectual property, that is, it is only valid in the confirmed and protected areas; 3, the timeliness of intellectual property rights, that is, only within the prescribed protection period. Ipabbr. 1。 Internet Protocol Computer Internet Communication Protocol 5. A police rank ip of the Hong Kong police is the abbreviation of inspector-level police: squad leader. 6. The abbreviation of I NTERpol ip is also the abbreviation of Interpol Inter National Criminal Police Organization. 7. Using IP (intellectual property) in the core (module) of intellectual property is an important feature of SOC construction. IP is defined as a pre-designed circuit function module used in ASIC or FPGA/CPLD. IP is divided into soft IP, fixed IP and hard IP. Soft IP core: a functional module described by Verilog HDL. Fixed IP core: the comprehensive function module has been completed, involving a lot of depth, and it is submitted to customers in the form of netlist file. Hard IP core: provide the final product of design-mask.
[Edit this paragraph ]IP registration
IP (Interrupt Priority) Interrupt Priority Control Register MCS-5 1 The interrupt priority control register IP in the single chip microcomputer is the basis for the user to control the service program of interrupt priority until the end of the program, execute the last return instruction and return to the main program, and then execute the command. If a bit in IP is set to 1, the corresponding interrupt is set to high priority, otherwise it is set to low priority. The format of the interrupt priority control register is as follows: ipd7D6D5D4 D3 D 1d0.
/ / / PS PT 1 PX 1 PT0 PX0
Bit address ///BCH BBH Bah B9H B8H
The meaning of IP valid control bit: PX0: the interrupt priority control bit of external interrupt 0, PX0= 1, and external interrupt 0 is defined as a high priority interrupt; PX0=0, and external interrupt 0 is defined as a low priority interrupt. PT0: interrupt priority control bit of timer/counter T0, PT0= 1, and timer/counter T0 is defined as high priority interrupt; PT0=0, and timer/counter T0 is defined as a low priority interrupt. PX 1: the interrupt priority control bit of external interrupt 1, where PX 1= 1 is defined as a high priority interrupt; PX 1=0, and external interrupt 1 is defined as low priority interrupt. PT 1: the interrupt priority control bit of timer/counter T 1 is defined as a high priority interrupt; PT 1=0 and timer/counter T 1 are defined as low priority interrupts. PS: serial interrupt priority control bit, PS= 1, serial interrupt is defined as high priority interrupt; PS=0, serial port interrupt is defined as low priority interrupt.