Shulou(Shulou.com)06/01 Report--

This article mainly explains "what are the advantages and disadvantages of CDN acceleration and the difference between two-line server". The content of the article is simple and clear, and it is easy to learn and understand. Please follow the editor's train of thought to study and learn "what are the advantages and disadvantages of CDN acceleration and what is the difference between two-line server"?

What is CDN?

The full name of CDN is Content Delivery Network, that is, content delivery network. Its purpose is to publish the content of the website to the "edge" of the network closest to the user by adding a new network architecture to the existing Internet, so that users can get the content they need nearby and improve the response speed of users visiting the website.

CDN is different from mirroring because it is smarter than mirroring, or it can be used as an analogy: CDN= 's smarter mirroring + caching + traffic diversion. Therefore, CDN can obviously improve the efficiency of information flow in Internet network. Technically, it comprehensively solves the problems of small network bandwidth, large number of user visits and uneven distribution of sites, so as to improve the response speed of users visiting the website.

To better understand CDN, let's take a look at the workflow of CDN. When a user visits a website that has joined the CDN service, the best CDN node closest to the user is determined by DNS redirection technology, and the user's request is directed to this node. When the user's request reaches the specified node, the CDN's server (the cache on the node) is responsible for providing the content requested by the user to the user. The specific process is as follows: the user enters the domain name of the website to be visited in his browser, the browser requests the resolution of the domain name from the local DNS, the local DNS sends the request to the main DNS of the website, the master DNS determines the most appropriate CDN node according to a series of policies, and sends the resolution result (IP address) to the user, and the user requests the content of the corresponding website from the given CDN node.

What is a double line?

Better dual-line access does not require the use of two IP addresses.

Full network routing or dual-line access is a link layer technology for network access. It means that the data center computer room where the server is located has a variety of network exits such as Netcom and telecom at the same time, and the whole network routing technology is set up on the upper switch of the computer room. so that the server can be automatically assigned to the fastest link every time it connects to the external network. As a result, both telecom and Netcom users can access at high speed at the same time.

However, this technology can solve the problem of interconnection during data output, but the connection initiated from your computer terminal to the server usually cannot automatically select the link mode, so the speed at which you upload data will still be affected by network interconnection problems. But usually we only need a very small amount of uploads to make a website, and most of them provide the web content to the viewer for download.

In addition to the whole network routing (two-line access), CDN technology can also achieve rapid access to each network. However, CDN technology will not only encounter slow upload, what is more troublesome is the limit of content cache and synchronization cycle, that is, your content can not be released in time, and users will always browse the information that lags behind.

Therefore, dual-line access has become the best solution for websites to solve the problem of interconnection.

Double-wire computer room is a unique product in such a special domestic network environment, double-line computer room can only solve the problem of Netcom and telecom access, but the link problems in network transmission and other ISP interworking problems have not been solved.

The principle of CDN is edge access, and visitors access data, which greatly shortens the transmission distance between visitors and the source site. It can solve all ISP interworking and network link problems.

Advantages of two-line computer room hosting:

Solve Netcom and Telecom access bottle well

No data synchronization problem

Disadvantages of two-line computer room hosting:

At present, the bandwidth of the two-line computer room in the market is severely limited.

The price is much more expensive than ordinary escrow.

Intelligent parsing is needed.

The server needs to move.

For the powerful enterprises can build their own double-line computer room, but the investment is too large, and the implementation is more complex, more difficult, it is better to choose CDN.

Advantages of CDN

Easy to maintain, automatic synchronization of website data

Resolve all ISP interworking issues and network link issues

Reduces the pressure on the source server

Effective resistance to DDOS attacks

Save backbone network resources

Shortcomings of CDN

Implementation complexity

Large investment

At present, most CDN only accelerates static content, but does not have a good effect on dynamic acceleration, while the effect of two-wire pair dynamic acceleration is the same as static.

Summary of the differences between CDN and two-line computer room:

The coverage of CDN is wider, and the two-line computer room only solves the Netcom and telecom access bottle well, but not the speed problem of one kilometer in the middle of the network (from the IDC to the telecommunications office where the user is located).

CDN is a good solution to solve the access speed and quality of large websites, as well as to solve the access bottle well problem of telecom and Netcom, and the dual-line computer room is a good choice to solve the access bottle well problem between Netcom and China Telecom.

If you do not want to increase any fees, do not change the existing state of the situation, to solve Netcom and telecom access bottle well problem choose to join the CDN alliance is the best solution.

Let's talk about the dual-line, multi-line server rental hosting pattern.

First, TieTong (Mobile, Unicom): there are many friends who host the server in TieTong (Mobile, Unicom).

In fact, putting the server on TieTong is almost a compromise between telecom users and Netcom users. for example, it takes 1 second for telecom users to open the website and 5 seconds for Netcom users to open the website. it may be 3 seconds for telecom and Netcom users to visit, which actually involves the waiting time that ordinary customers are willing to tolerate. For example, ordinary people tolerate the opening of a website for 4 seconds, then TieTong is a very good solution, so that telecom users and Netcom users can tolerate it. But for example, if the server is used for video teaching, then this approach is not very good, which will slow down the access speed of telecom and Netcom users. Put in TieTong, the price is generally cheaper (relative to the real dual-line computer room), if friends mainly do WEB, members are not particularly high speed, then you choose TieTong is a good plan.

2. Dual-line dual-IP hosting

This situation can be subdivided according to whether there are two public network exits:

1. Having two public network exits: the effect of such dual-line dual-IP hosting is better, but the hosting price is relatively high, and the bandwidth resources are also relatively expensive. This kind of computer room resources are very scarce. At present, there is only one dual-line computer room with two public network exits in the country, because the State Administration of Radio, Film and Television does not allow Telecom and Netcom to engage in dual-line computer rooms. I feel that this is a great blow to the business of Telecom and Netcom, which is not conducive to the development of Telecom and Netcom. Now the only dual-line computer room with a public network exit is because it has been applied for in 2000, and it is difficult to cancel it, and the later applications have not been approved.

2, do not have their own public network exit: such custodians generally pull 100m exclusive optical fiber from telecom, Netcom pull 100m exclusive optical fiber, and then buy some IP separately, which is now almost the most seen dual-line on the market, and generally such agents do not have very good technology and equipment, and need to set up double IP through dual network cards, while the computer room, equipment and technical force with public network exit are all good. All binds dual IP through a single network card.

In fact, one of the biggest features of this model is that the connection between 100m exclusive optical fiber and the switch of the operator is 100m (it can also be understood as 100m exclusive on the metropolitan area network), rather than 100m on the exit of the public network. It is estimated that the general provincial capital city 100m exclusive optical fiber can generally be allocated to about 20m on the public network exit, which is based on the overall bandwidth resources of the city. If the city's bandwidth resources are very loose, it is possible that the 100m exclusive on the metropolitan area network can also run high on the public network exit.

3. Have a public network exit: in fact, none of the agents in this model have their own small computer room. He does business in the telecom rental cabinet, and then hosts a machine in Netcom, buys a section of IP, and acts as a proxy server. This can also help customers set up 2 IP on the server, but in this way, the resolution speed of Netcom lines through the proxy server is slower, and the network access speed is slower. So this effect is not very good, friends in the choice of dual-line when trying not to choose such dual-line hosting.

III. Dual-line single IP hosting

1, there is a public network export: such custodians already have such good resources, such as telecom, their effect is better, and it is a single IP implementation, but such resources are also very scarce, and the general custodian has no way to get such resources, and there is the Zhengzhou Jing'an data center where Yuwang is located, using BGP technology to achieve, but the stability is really disappointing.

2. There is no public network exit: that is, pulling the optical fiber from Telecom and Netcom, and then setting up the route through the equipment, that is, assigning an IP to the user to achieve dual lines, but for the time being, we have not seen a very good effect in the market, and the reputation is good, probably because there is no public network exit, and the equipment is not advanced enough.

With this knowledge, let me talk about how to choose:

First of all, let's talk about dual IP hosting.

Zhengzhou two-line computer room (good technical and environmental facilities, good stability, but can not put SF, bandwidth allocation is also quite sufficient-- the bandwidth of each machine is exclusive of 5m, which is absolutely cost-effective among similar two-line computer rooms in the country. 59)

If it is a single-line hosting, it is recommended not to choose Shanghai, although Shanghai's computer room environment and all aspects can be said to be the best location of the computer room in China. But the big computer rooms, including Zhangjiang, Waigaoqiao, Wusheng and so on, are basically full. Shanghai has dragged too many servers, now put the server in the past, there is no good bandwidth for you.

In terms of telecommunications, you can choose Changchun, Chongqing, Guangdong, Jiangxi Telecom, Xi'an Telecom, etc.

For Netcom, you can choose Henan Netcom, Zhengzhou second Chief Netcom and Shanghai Netcom (less bandwidth and high price).

Thank you for your reading. The above is the content of "what are the advantages and disadvantages of CDN acceleration and what is the difference between two-line servers". After the study of this article, I believe you have a deeper understanding of what is the difference between the advantages and disadvantages of CDN acceleration and two-line servers. Here is, the editor will push for you more related knowledge points of the article, welcome to follow!

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.