Thoughts on IDC dual-line technology

China North and South Telecom split their families earlier. I personally think it is the biggest failure of the Ministry of Information Industry. Now, China Netcom is also to be demolished, which are classified as mobile and New China Unicom, leading to bottlenecks in informatization, this is the problem of North-South communication. If the data center is located in the data center of North China Netcom, access to users of southern China Telecom will be more or less affected, and the interests will not be ruled out to drive human intervention, the author's region has experienced China Telecom and the leaders deliberately pulling out the network cable. This can be a hooligans. the Relationship Between China Telecom and China Netcom is also clever in every place. Insiders of China Telecom revealed that China Telecom lines cannot be connected to or even to telecom data centers, regardless of the customer's needs. this results in the customer to bear huge extra costs, and ultimately falls on the consumer itself. on the one hand, CPI remains high. On the one hand, these monopoly industries are constantly merged and then merged. I wonder why we should not study the business model of the civil aviation industry. The separation of management right and experience right means that the airport manages the airport, the aviation business manages the aviation business, and the airport will only achieve a win-win situation, the aviation business will only compete, and the ultimate benefit is consumers.
If the problem is incorrect, let's talk about this dual-line solution, The concept of Dual-line is widely used in the international and domestic markets. Currently, there are three mainstream technologies in China: Single-IP dual-line, dual-IP dual-line, and CDN multi-line. In a single IP address and multiple lines, the difference between the traditional single IP address dual line and the BGP Single IP dual line is derived. The following describes the dual-line and multi-line applications of IDC:

1) traditional single IP dual-line

A single IP address dual-line is an IP address set on the server. The IP address is a China Netcom IP address or a China Telecom IP address, configuring data packets through a routing device is a two-line technique developed through a telecom network or a Netcom network. This solution can also improve the access speed between China Netcom users and telecom users, and solve the problem that dual-IP dual-line routing needs to be set on the server. However, because the IP address uses the IP address of China Netcom or China Telecom, the access user does not automatically identify the best route when sending request data packets. Therefore, this solution can only be a semi-dual technical solution and a transitional solution. This scheme is generally a temporary scheme adopted by a single-line IDC service provider during the transition to a dual-line IDC service provider.

2) Single-IP dual-line implemented by BGP

The Border Gateway Protocol (BGP) is mainly used for interconnection between autonomous systems (AS) on the Internet. The main function of BGP is to control route propagation and select the best route. China Netcom and China Telecom both have the as number (Autonomous System number). Most of the major network operators in China are interconnected with their as numbers through the BGP protocol. To use this solution for dual-line deployment, you must apply for the idc ip address segment and as number at CNNIC (China Internet Information Center, then, the IP address segment is broadcast to other network operators such as China Netcom and China Telecom through the BGP protocol, after the BGP protocol is used for interconnection, all the Backbone Routing devices of China Netcom and China Telecom determine the optimal route to the IP address segment of the IDC to ensure high-speed access for China Netcom and telecom users.

Using the BGP protocol to implement dual-line Single IP addresses can help your applications achieve optimal access routing on the network to improve access speed. The BGP protocol itself contains the redundant routing function, it can also automatically back up and switch the dual-line routing of the network. BGP can also help to expand and enhance the dual-line network to achieve multi-line support.

3) Dual-IP dual-line implementation

Dual-IP dual-line implementation means that two NICs are installed on one server, connected to the telecom network cable and the Netcom network cable respectively, and one Netcom IP address and one Telecom IP address are set, in this way, a server has two IP addresses. You need to add a route table of China Netcom or China Telecom to the server to enable access from different lines between China Netcom users and China Telecom users. Dual-IP dual-line has two common usage methods:

The ICP user sets two different links on the website. The Netcom user clicks the Netcom IP address to access the server, and the telecom user clicks the Telecom IP address to access the server;

Bind9 (DNS server software) is used to return different Server IP addresses for different IP address requests to implement the IP address returned by the Netcom user when requesting a domain name, when a telecom user requests a domain name, it returns the Telecom IP address. This method is the smart DNS solution proposed by some IDCs.

Dual-IP dual-line improves the speed for China Netcom and telecom users to access the website. However, the disadvantage is that the dual-nic must be configured on the server to access the server, this increases the maintenance difficulty for common users, and all data packets need to be routed on the server and then sent to different NICs. When the traffic volume is large, server resources occupy a lot. This solution is the simplest dual-line solution, which is generally used by small IDC providers.

4) implement multiple lines in CDN Mode

CDN is called contentdeliverynetwork in English. It is a virtual network that is built and covered on the Internet and is composed of node server clusters distributed in different regions, CDN can efficiently and stably publish website content to the nearest place to netizens.

Many of my friends have mixed CDN with smart domain names, saying that CDN is used for multi-server network-based hosting and smart domain name DNS. However, although CDN is similar in terms of function implementation, the implementation principle of the function is not a simple addition.

The working principle of CDN is that multiple servers are placed on different network nodes and bufferedProgramAutomatically captures data from the user's source server and caches the data on servers of nodes of different network segments. Based on this, the smart DNS server's sub-network resolution function is used, different network users can access the websites on the nearest network segment, so as to avoid the impact of network problems on the Website access speed.