Internet Infrastructure

ISP: An Internet service provider

The Internet came into being over a long period of time and in three stages. From the packet switched network ARPANET started in 1969, to the three-level structure (backbone, regional network, Internet) Internet in the 1990s, and finally to the multi-layer ISP structure that we are using now. We don’t have to worry too much about how it came to be, but we need to focus on the multi-level ISP architecture of the Internet that we’re using now.

Internet Service Provider (ISP) is an Internet Service Provider. Although listen to the name a little confused, but after listening to the following introduction will suddenly enlightened. For example, China’s typical several large ISP: China Telecom, China Unicom, China Mobile and so on. Isps can apply for many IP addresses from Internet management organizations, and they have multiple communication lines and routers and other networking devices. Their individual or collective users only need to pay corresponding fees to THE ISP to use the IP rights assigned to them and connect to the Internet by this IP. Therefore, the network used in the world today is not owned by a single group or organization, but by numerous ISPs, large and small.

According to the area covered by ISPs and the number of IP addresses, ISPs are classified into trunk ISP, regional ISP and local ISP. Backbone ISPs are maintained and created by several specialized companies and have the largest area of service (usually covering the entire country). Regional ISPs are smaller ISPs that are connected through one or more backbone ISPs. Local ISPs provide direct services to users, which can be companies, businesses or universities.

As long as every local ISP is equipped with a router and connected to a local ISP, and all local ISPs are also connected to the backbone ISP, all the distribution tasks in the Internet can be completed under the cooperation of these interconnected ISPs.

However, with the rapid increase of the number of Internet users, people began to study Geng Kuaiosu’s forwarding group and how to use network resources more effectively, so the Internet Exchange Point (IXP) came into being.

IXP: Internet switching center

Internet Exchange Point is a centralized Exchange platform established by different telecom operators to connect their respective networks. Referred to as IX or IXP in foreign countries, Internet Exchange Point is generally operated by a third party in a neutral manner and is an important infrastructure of the Internet. Overseas well-known IX include AMS-IX, HKIX (Hong Kong Internetworking Exchange Center), Equnix IX, etc. In China, there is Beijing, Shanghai and Guangzhou Internet Exchange Center established under the leadership of the government, but it has disappeared in name for various reasons. Well-known third party IX in China include We IX (Chi Link Network) located in Shanghai, etc.

The role of IXP

IXP allows two networks to connect directly and swap packets without the need for a third network to forward packets. For example, when host A and host B switch packets, they do not need to go through the backbone ISP of the uppermost layer, but directly switch packets between the two ISPs. In this way, the division of data traffic is more reasonable, the delay is reduced, and the cost is reduced.

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