What are the reasons and functions of IP address classification?
Current IP networks use 32-bit addresses, expressed in dotted decimal notation, such as 172.16.0.0. The address format is: IP address = network address + host address or
IP address = host address + subnet address + host address. The setting of the subnet mask follows certain rules. It is the same as the IP address. The length of the netmask is also 32 bits. The left side is the network bit, represented by the binary number "1"; the right side is the host bit, represented by the binary number "0".
Subnet division is actually the process of designing a subnet mask. The subnet mask is mainly used to distinguish the network ID and host ID in the IP address. It is used to shield part of the IP address and separate the network ID and host ID from the IP address. The subnet mask is composed of 4 decimal numbers. The composed value is separated by "." in the middle, such as 255.255.255.0. If it is written in binary form: 11111111.11111111.11111111.00000000, where the "1" bit separates the network ID, and the "0" bit separates the host ID, that is, the network number is obtained by performing an "AND" operation on the IP address and the subnet mask.
The subnet mask does not exist alone, it is used in conjunction with the IP address. The function of the code is to divide an IP address into two parts: a network address and a host address.
IP addresses are divided into 5 types according to different network IDs, Class A addresses, Class B addresses, and Class C addresses. address, Class D address and Class E address. So how to divide IP addresses?
1. Class A IP address
A Class A IP address consists of a 1-byte network address and It consists of a 3-byte host address. The highest bit of the network address must be "0". The address range is from 1.0.0.0
to 126.0.0.0. There are 126 Class A networks available, and each network can accommodate it. More than 100 million hosts.
2. Class B IP address
A Class B IP address consists of a 2-byte network address and a 2-byte host address. The highest bit of the address must be "10", and the address range is from 128.0.0.0 to 191.255.255.255. There are 16382 Class B networks available, and each network can accommodate more than 60,000 hosts
. p>
3. Class C IP address
A Class C IP address consists of a 3-byte network address and a 1-byte host address. The highest bit of the network address must be "110". The range is from 192.0.0.0 to 223.255.255.255. There are more than 2.09 million Class C networks, and each network can accommodate 254 hosts.
4. Class D addresses are used for multicast.
The first byte of the Class D IP address starts with "lll0". It is a specially reserved address. It does not point to a specific network. Currently, this type of address is used in multicast ( Multicast). The multicast address is used to address a group of computers at a time. It identifies a group of computers that share the same protocol.
5. Class E IP address
Starting with "llll0", reserved for future use
An all-zero ("0.0.0.0") address corresponds to the current host's IP address ("255.255. 255.255") is the broadcast address of the current subnet.
Among the three main types of IP addresses, three areas are reserved as private addresses, which are more commonly used IP addresses.
The address range is as follows:
Class A address: 10.0.0.0～10.255.255.255
Class B address: 172.16.0.0～172.31.255.255
Class C Address: 192.168.0.0～192.168.255.255
(1) Class A address
The representation range of Class A address is: 0.0.0.0～126.255.255.255, and the default network mask is : 255.0.0.0, Class A network uses the first set of numbers to represent the address of the network itself, the next three sets of numbers are used as the address of the host connected to the network, that is, the high-order bit is 0, the next 7 bits represent the network ID, and the remaining 24 bits represent Host ID. Class A addresses are assigned to networks with a large number of hosts (direct individual users) and a small number of LANs. For example, IBM's network.
Class A addresses are suitable for situations where there are fewer networks and more nodes. The number of networks is 128, and the number of nodes in each network is 1,600.
(2) Class B address
The representation range of Class B address is: 128.0.0.0~223.255.255.255, and the default network mask is: 255.0.0.0. Class B addresses are assigned to generally medium-sized networks. Class B networks use the first and second sets of numbers to represent the network address. The last two sets of numbers represent the host address on the network, that is, the high-order bit 10. The next 14 bits represent the network ID, and the remaining 16 bits represent the host ID.
Class B addresses are suitable for situations where the number of networks and nodes is moderate. The number of networks is 16,000 and the number of nodes per network is 64,000.
(3) Class C address
The representation range of Class C address is: 192.0.0.0.～223.255.255.255, the default network mask is: 255.255.255.0; Class C address Assigned to small networks, such as general LANs and campus networks, the number of hosts that can be connected to it is the smallest, and the users are divided into several network segments for management. Class C networks use the first three groups of numbers to represent the network address, the last group of numbers as the host address on the network, that is, the high-order bit 110, the next 21 bits represent the network ID, and the remaining 8 bits represent the host ID.
Class C addresses are suitable for situations where there are a large number of networks and a small number of nodes. The number of networks is 2 million and the number of nodes in each network is 256.
For example, you say "131.108.1.56 subnet mask 255.255.255.0
This IP and subnet mask are the same. Can it be said that the address belongs to B and the mask belongs to C? ", is inappropriate. Subnet masks do not belong to the classification of IP addresses. What is an IP address? How are IP addresses classified?
The IP address is an address used to uniquely identify each host or device in the TCP/IP network. The IP address consists of a 32-bit (*** four octets) binary number. The IP address is divided into Two parts, the left network number part is used to identify the network where the host is located; the right part is used to identify the host itself. Hosts connected to the same network must have the same network number.
Different types of IP addresses are distinguished by the leading bit (highest bit) of the IP address: How many types of IP addresses are there? How is it classified?
Definition of IP protocol, classification and characteristics of IP address
What is IP protocol, how is IP address represented, how many categories are it divided into, and what are the characteristics of each?
In order to facilitate addressing and hierarchical network construction, IP addresses are divided into five categories: A, B, C, D, and E. Only A is used in commercial applications
, B and C categories.
IP Protocol (Inter Protocol), also known as Internet Protocol, is a datagram protocol that supports interconnection between networks.
Together with TCP Protocol (Transmission Control Protocol), it constitutes the TCP/ The core of the IP protocol suite.
It provides complete functions for network connections, including IP datagrams that specify the IP address format within the interconnection network.
On the Internet, in order to achieve communication between nodes connected to the Internet,
each node (computer connected to the network) must be assigned an address, and this should be guaranteed The address is unique in the entire network.
This is the IP address.
The current IP address (IPv4: IP version 4) is represented by 32 binary bits, and each 8-bit binary number is an integer,
separated by decimal points in the middle, such as 159.226. 41.98, the entire IP address space has four groups of 8-bit binary numbers,
consisting of the address of the network where the host is located (similar to the number of the army) and the identification of the host in the network (like a soldier
The number of the unit)*** is composed of the same.
In order to facilitate addressing and hierarchical network construction, IP addresses are divided into five categories: A, B, C, D, and E.
Only A, Category B and C.
* Class A address: The network identification of a Class A address is represented by the first group of 8-bit binary numbers.
The host identification in the network occupies 3 groups of 8-bit binary numbers.
p>
The characteristic of Class A addresses is that the first binary digit of the network identifier must be "0".
It is not difficult to calculate that Class A addresses allow 126 network segments, and each network allows approximately 16.7 million hosts. They are usually allocated to networks with a large number of hosts (such as backbone network).
* Class B address: The network identification of the Class B address is represented by the first two sets of 8-bit binary numbers.
The host identification in the network occupies two sets of 8-bit binary numbers.
p>
The characteristic of Class B addresses is that the first two binary digits of the network identifier must be "10".
Class B addresses allow 16384 network segments, and each network allows 65533 hosts. It is suitable for networks with many nodes
(such as regional networks).
* Class C address: The network identification of the Class C address is represented by the first three groups of 8-bit binary numbers.
The host identification in the network occupies one group of 8-bit binary numbers.
The characteristic of Class C addresses is that the first three binary digits of the network identifier must be "110".
A network with a Class C address allows 254 hosts and is suitable for networks with relatively few nodes (such as campus networks).
In order to facilitate memory, it is usually customary to use four decimal numbers to represent an IP address.
The decimal numbers are separated by periods "."
This method of representing IP addresses is also called dotted decimal notation. Expressed in this way,
The IP address range of Class A network is 1.0.0.1-127.255.255.254;
The IP address range of Class B network is: 128.1.0.1- 191.255.255.254;
The IP address range of Class C networks is: 192.0.1.1-223.255.255.254.
Due to the shortage of network addresses and the relative surplus of host addresses, a subnet mask is used to specify the network segment number.
The TCP/IP protocol has nothing to do with the lower data link layer and physical layer, which is also an important feature of TCP/IP. Because of this, it can widely support physical network structures composed of lower two-layer protocols. At present, TCP/IP connections have been used to form intercontinental networks, national networks and cross-regional networks.
How are IP addresses classified?
IPv4 addresses are divided into categories A, B, C, D, and E: Category A: 1.0.0.0~126.255.255.255, default subnet mask/8, which is 255.0 .0.0 (127.0.0.0~127.255.255.255 is the loopback address, used for local loopback testing and other purposes); Class B: 128.0.0.0~191.255.255.255, default subnet mask/16, which is 255.255.0.0; Class C: 192.0.0.0~223.255.255.255, default subnet mask /24, which is 255.255.255.0; Class D: 224.0.0.0~239.255.255.255, generally used for multicast Class E: 240.0.0.0~255.255.255.255 (255.255.255.255 is the network-wide broadcast address). Class E addresses are generally used for research purposes. There is also a private address in IPv4, which is the address used by the internal LAN, respectively: 10.0.0.0~10.255.255.255; 172.16 .0.0~172.31.0.0; 192.168.0.0~192.168.255.255 How are IP addresses classified?
The IP address is an address used to uniquely identify each host or device in the TCP/IP network. The IP address is A 32-bit (*** four octets) binary composition, the IP address is divided into two parts. The left network number part is used to identify the network where the host is located; the right part is used to identify the host itself. Hosts connected to the same network must have the same network number.
Different types of IP addresses are distinguished by the leading bit (highest bit) of the IP address:
Class A address: 0nnnnnnn.hhhhhhhh.hhhhhhhh.hhhhhhhh
Class A addresses have a 7-digit network number, so 125 Class A networks can be defined {27-2 (the network number cannot be all 0s or all 1s)-1 (127 is the loopback address)} The number of hosts each network can have It is 16777214{224-2 (the host bit cannot be all 0 or all 1)}
Decimal representation range: 1.0.0.1-126.255.255.254
Class B address: 10nnnnnn.nnnnnnnn .hhhhhhhh.hhhhhhhh
A Class B address has a 14-bit network number, so 16382 Class B networks {214-2} can be defined.
The number of hosts each network can have is 65534 {216-2}
Decimal representation range: 128.0.0.1-191.255.255.254
Class C address: 110nnnnn.nnnnnnnn.nnnnnnnn.hhhhhhhh
Class C Addresses have a 21-bit network number, so 2097152 Class C addresses {221-2} can be defined
The number of hosts each network can have is 254{28-2}
Decimal Representation range: 192.0.0.1-223.255.255.254
Class D address: 1110xxxx.xxxxxxxx.xxxxxxxx.xxxxxxxx
Class D address is used for multicast, the first 4 digits are 1110, and the last 4 digits are 1110. 28 bits are the multicast address ID.
Decimal representation range: 224.0.0.0-239.255.255.255
Class E address: always booted with 1111 four digits
Class E address is for research purposes
Decimal representation range: 240-
IP addresses are uniformly allocated by InterNIC (Internet Information Center) to ensure the uniqueness of IP addresses. However, there is a type of IP address that can be obtained directly without applying. Used for corporate intranets, this is the Private Address. The Private Address will not be forwarded by any router on the INTERNET. To access the INTERNET, you must go through NAT/PAT conversion and access it in the form of a public IP.
These private addresses are:
10.0.0.0-10.255.255.255 (one class A address)
172.16.0.0-172.31.255.255 (16 Class B addresses)
192.168.0.0-192.168.255.255 (256 Class C addresses)
How are IP addresses classified?
The IP address is composed of 24-bit binary numbers and is divided into four groups. For example: 192.168.0.1 is an IP address.
IP classification is based on the range in which the first digit falls.
IP addresses can be divided into the following categories of addresses:
Class A IP address range 1.0.0.0 to 127.255.255.255
Class B IP address range 128.0.0.0-191.255.255.255
Class C IP address range 192.0.0.0-223.255.255.255
Class D IP address range 224.0.0.0 to 239.255.255.255
Taking 192.168.0.1 just now as an example, we check the first digit, which is 192, and within the range, we check that it exactly belongs to the address range of Class C. How are IP address ranges classified?
Current IP networks use 32-bit addresses, expressed in dotted decimal notation, such as 172.16.0.0. The address format is: IP address = network address + host address or IP address = host address + subnet address + host address.
IP address type:
When the Internet was originally designed, in order to facilitate addressing and hierarchical network construction, each IP address included two identification codes (ID), namely network ID and host ID. All hosts on the same physical network use the same network ID. A host on the network (including workstations, servers, routers, etc.) on the network has a host ID corresponding to it. IP addresses are divided into 5 types according to different network IDs: Class A addresses, Class B addresses, Class C addresses, Class D addresses and Class E addresses.
1. Class A IP address:
A Class A IP address consists of a 1-byte network address and a 3-byte host address. The highest bit of the network address must be "0", and the address range is from 1.0.0.0 to 126.0.0.0. There are 126 Class A networks available, each of which can accommodate more than 100 million hosts.
2. Class B IP address:
A Class B IP address consists of a 2-byte network address and a 2-byte host address. The highest bit of the network address must be "10", and the address range is from 128.0 .0.0 to 191.255.255.255. There are 16,382 Class B networks available, and each network can accommodate more than 60,000 hosts.
3. Class C IP address
A Class C IP address consists of a 3-byte network address and a 1-byte host address. The highest bit of the network address must be "110". The range is from 192.0.0.0 to 223.255.255.255. There are more than 2.09 million Class C networks, and each network can accommodate 254 hosts.
4. Class D addresses are used for multicast (Multicast).
The first byte of the Class D IP address starts with "lll0", which is a specially reserved address. It does not point to a specific network. This type of address is currently used in multicast (Multicast). A multicast address is used to address a group of computers at a time. It identifies a group of computers that share the same protocol.
5． Class E IP addresses
Start with "llll0" and are reserved for future use. An all-zero ("0.0.0.0") address corresponds to the current host. The IP address with all "1"s ("255.255.255.255") is the broadcast address of the current subnet.
Among the three main types of IP addresses, three areas are reserved as private addresses. The address ranges are as follows:
Class A addresses: 10.0.0.0～10.255.255.255
Class B address: 172.16.0.0～172.31.255.255
Class C address: 192.168.0.0～192.168.255.255
The first group of numbers of the Class A address It is 1~126. Note that the numbers 0 and 127 are not used as Class A addresses, the number 127 is reserved for the internal loopback function, and the number 0 indicates that the address is the local host and cannot be transmitted.
The first group of numbers for Class B addresses is 128 to 191.
The first group of numbers for Class C addresses is 192 to 223.
The representation range of various types of addresses:
1. Class A address
The representation range of Class A addresses is: 0.0.0.0~126.255.255.255, default The network mask is: 255.0.0.0; Class A addresses are allocated to particularly large networks. Class A networks use the first set of numbers to represent the address of the network itself, and the next three sets of numbers as the addresses of hosts connected to the network. Assigned to large networks with a large number of hosts (direct individual users) and a small number of LANs. For example, IBM's network.
2. Class B address
The representation range of Class B address is: 128.0.0.0~191.255.255.255, and the default network mask is: 255.255.0.0; Class B address is assigned to A typical medium-sized network. Class B networks use the first and second sets of numbers to represent the network address, and the last two sets of numbers represent the host address on the network.
3. Class C address
The representation range of Class C address is: 192.0.0.0~223.255.255.255, and the default network mask is: 255.255.255.0; Class C address is assigned to Small networks, such as general local area networks and campus networks, have the smallest number of hosts that can be connected, and the users are divided into several network segments for management. Class C networks use the first three sets of numbers to represent the network address, and the last set of numbers as the host address on the network.
4. In fact, there are also Class D addresses and Class E addresses. However, these two types of addresses have special uses. Here is a brief introduction: Class D addresses are called broadcast addresses and are used by special protocols to send information to selected nodes. Class E addresses are reserved for future use. What is the IP address 231.0.0.1? What is its specific function? Please help.
Class D address does not distinguish between network address and host address. The first four digits of its first byte are fixed to 1110. .
⑵ Class D address range: 224.0.0.1 to 239.255.255.254
Class D addresses are used for multicast.
The first byte of the Class D IP address starts with "lll0", which is a specially reserved address. It does not point to a specific network. This type of address is currently used in multicast (Multicast). A multicast address is used to address a group of computers at a time. It identifies a group of computers that share the same protocol. What is the role of trademark classification?
Commodity classification is also the basic unit for applying for trademark registration procedures and paying fees.
As we all know, a trademark is a sign that distinguishes the source of goods or services. Each registered trademark is designated for a certain product or service. For example, when it comes to Changhong, people will think of color TVs; when it comes to Maotai, people will think of wine; when it comes to Maxam, people will think of cosmetics and so on. It should be said that there is no trademark that exists independently of goods or services. Therefore, when applying for trademark registration, correctly describing the goods or services to be designated and their categories are the first problems that trademark applicants (agents) will encounter.
Many different departments need to classify goods for management, statistics and other work needs. For example, from the perspective of national economic management, commodities are usually divided into two categories: industrial products and agricultural products. Industrial products are further divided into heavy industrial products and light industrial products. Heavy industrial products can be further divided into metallurgical industrial products, mechanical industrial products, etc. The national trademark authority also needs to classify goods for the purpose of trademark registration and management. Trademark registration and management should be said to be a large and complex systematic project, and the classification of goods and services is a basic work of the Trademark Office. There are currently more than 7 million registered trademarks in our country. Without a scientific classification management system, it is almost impossible to search, query, and read a trademark, just like finding a needle in a haystack.
It is precisely for the needs of trademark search, review, and management that certain goods with the same attributes are grouped together into one category, and all goods and services are divided into The 45 categories form the "Classification of Goods and Services for Trademark Registration" that we are going to describe here. For example, "industrial oils and greases, lubricants, supplies for absorbing, spraying and bonding dust, fuels (including gasoline for motors) and lighting agents, candles, wicks", etc. are grouped together to form one category (Category 4) ; Another example is to combine "surgical, medical, dental and veterinary instruments and instruments, prosthetic limbs, prosthetic eyes and teeth, orthopedic supplies, suture materials" to form another category (Category 10). The search and retrieval system of the Trademark Office is established according to the categories of goods and services; the "Trademark Announcement" is organized according to categories; applicants must apply for trademark registration according to categories; the trademark registration certificate issued by the Trademark Office to the registrant must also be marked. Goods or services and their categories.
Commodity classification is also the basic unit for applying for trademark registration procedures and paying fees. That is, to apply for registration of a trademark in a category, you need to go through one procedure and pay one basic fee. For example, if an applicant applies for a registered trademark on medical chemicals, proprietary Chinese medicines, Chinese herbal medicines, medicated wine, medical nutrition products, air purification preparations, veterinary drugs, pesticides, sanitary napkins, and dental fillings, although there are as many as ten designated products, Since these products all belong to the same category (5 categories), you only need to go through one procedure and pay one basic fee (i.e. one bid per category). Although the trademark applied for registration by another company only needs to be used on painting pens and paints, it needs to fill in two applications, apply separately in two categories, and pay two basic fees, because these two products belong to two categories respectively. There are two categories, namely, painting pens belong to category 16 and painting pigments belong to category 2.
In the past, the trademark authorities of each country formulated their own commodity classification tables based on their own national conditions and understanding of the products for use by trademark authorities and trademark registration applicants. The product classification list is not static. It will be gradually increased and revised with the enrichment of commodities and people's understanding of commodities. Since 1923, our country has formulated and published five commodity classification tables.
By the 1950s, the world economy had achieved greater development and international exchanges had become more frequent. Some countries believe that each country's use of its own commodity classification table cannot adapt to international connections on trademark matters, causing trouble for trademark owners to register abroad, and is not conducive to the development of the trademark industry and economic development. The trademark authorities of these countries believe that there is a need for an internationally unified commodity classification table for trademark registration. In this case the Nice Agreement was born.
The role of international classification
The Nice Agreement is an international convention attended by many countries. Its full name is the Nice Agreement on the International Classification of Goods and Services for the Purpose of Trademark Registration. The agreement was signed in Nice, a city in southern France, on June 15, 1957, and came into effect on April 8, 1961. The number of member states of the Nice Agreement has grown to 65. Our country joined the Nice Union on August 9, 1994. The purpose of the Nice Agreement is to establish a consistent international classification system for goods and services for trademark registration and ensure its implementation. At present, the international classification system includes 45 categories, including 34 categories of goods and 11 categories of services. The system contains more than 10,000 goods and services. The goods and services that applicants need to report are generally included. This classification is used not only by all Nice Union member states, but also by non-Nice Union member states. The difference is that members of the Nice Union can participate in the revision of the classification list, while non-member states have no right to participate. At present, more than 130 countries and regions in the world have adopted this classification table. my country has adopted international classification since November 1, 1988, which has greatly facilitated trademark applicants, further standardized the management of trademark authorities, and closer ties with international trademark affairs. Especially since my country joined the Nice Agreement in 1994, we have actively participated in the modification and improvement of the Nice Classification, and have added a number of goods with Chinese characteristics to the Nice Classification. The Nice Classification is revised regularly, firstly by adding new goods, and secondly by adjusting the goods already included in the classification according to new perspectives in order to make the goods more intrinsically unified. The tenth edition of the Nice Classification came into effect on January 1, 2012.
The Nice Classification consists of two parts, one is a classification of goods and services arranged by category, and the other is a classification of goods and services arranged in alphabetical order.
The classification table arranged by category arranges goods and services in the order of categories 1-45. Each category has a category number and title. The title of each category summarizes the characteristics and scope of the goods included in this category. Finally, it lists all the goods or services included in this category. Each product or service has a sequence number. Easy to find. In addition, each category has an annotation, which explains what products this category mainly includes, how this category is distinguished from related categories of products, and how to classify marginal products. This annotation is very helpful in classifying some easily confused products. . For example, the third category is titled "Bleaching agents and other materials for laundry use, preparations for cleaning, polishing, stain removal and grinding, soaps, spices, essential oils, cosmetics, perfumes, toothpastes and toothpowders." The annotation is: "This The category mainly includes bath products and cosmetics. In particular, it includes: personal deodorants; cosmetic hygiene products. In particular, it does not include: chemicals for cleaning chimneys (Category 1); stain removal products used in the production process (Category 1). ; Deodorants not for personal use (Class 5); Pumice stones or hand-grinding wheels (Class 8)
Another section is an alphabetical list of goods and services provided by the World Intellectual Property Organization. It has published a classification table of goods and services in English and French order. my country’s trademark authority has also compiled and printed a classification table of goods and services in Chinese pinyin order. Using this table is as convenient as looking up the categories of general goods in a dictionary. . For example, a company that produces televisions and video cameras wants to apply for trademark registration on these two products. According to the Chinese pinyin order, it can be easily found that both products belong to Category 9; another example is that a company Enterprises that produce food need to apply for trademark registration on milk and ice cream. With the help of this form, you can quickly find out that these two products belong to Class 29 (Milk) and Class 30 (Ice Cream).