Recently, a domestic operator issued a strict investigation of PCDN news, which has attracted widespread attention inside and outside the industry. The operator said that when a user's broadband account has an "abnormally large amount of uplink broadband occupation", the account may be banned. If the user complains, the customer service will arrange a broadband master to come to the door to "collect evidence", and then unblock it according to the situation. In this verification operation, it is necessary to do - "all should be investigated, all should be stopped, and all should be dismantled". What are the reasons for the "abnormally large traffic uplink broadband occupation", and how will operators mobilize the public? The answer is PCDN. Don't think this question has nothing to do with you. In fact, many users have this PCDN at home. If you accidentally use it, you may really be banned and unable to access the Internet. What is PCDNWhat exactly is PCDN? Why is it being used by carriers**? To put it simply, PCDN is P2P+CDN. English full name: peer to peer content delivery network, Chinese full name: peer-to-peer content delivery network.
P2P, everyone should be familiar with it. The notorious P2P financial management in the past few years, as well as the P2P** that was popular all over the Internet earlier, are all based on P2P. P2P is a typical decentralized concept. It focuses on the business relationship between individuals and individuals. Take P2P** as an example. Traditionally, there is one server and n clients. All clients, go to the server ** data (movies). 
In the case of P2P, user A is a part, and user B is also a part. Then, user A and user B share each other's existing data. In this way, the pressure on the server is reduced.
Even if the server is shut down, it will not affect the remaining users to complete all the data. The famous BT (BitTorrent) is P2P. After it became popular that year, it was unanimously welcomed by the majority of users. Until now, it has been an important means of ** movies. It embodies the Internet spirit of "all for one, one for all". Let's talk about CDN. CDN technology, Xiao Zaojun has done science popularization with you before (what is CDN?) ）。To put it simply, CDN is one of a kindEdge computingThought. Traditionally, I put the movie on the main server and everyone came to pick it up, which was a big burden on the server and had a bottleneck in bandwidth. So, I made a lot of copies of the movie and put it on a regional server closer to the user. In this way, "distribution of content" is realized. The pressure on the main server is less, and users are not easy to freeze when watching movies.
PCDN, which is a combination of P2P and CDN technology, is a CDN based on P2P technology. It goes even further, putting the content directly in the user's home, such as the mobile terminal, or the router, and turning it into a larger "content source". 
For example, you use a certain **app** to play the series "Flowers". Other nearby users, if they also ** "Flowers", will take a part of the data from your mobile phone. For another example, you use a network disk app and a copy of an e-book. Other nearby users, if they want to ** this e-book, can access the data from your mobile phone. The PCDN on the client can not only be implemented through the mobile app, but also can be directly deployed on the wireless router. That's right,In recent years, all kinds of xx routing treasure、Money making treasure、Money-making treasure,Essentially, it is a router with PCDN function。 In addition to basic Internet access, it will use the uplink bandwidth to provide services to other users. The more the uplink bandwidth contributes, the richer points or virtual currency rewards will be, which can be exchanged for gifts or even cash in the so-called "**" of the service provider. Many users feel that this wool is worth picking. In any case, it is also good to subsidize the cost of electricity and Internet bills. Why pcdnSo, why is this seemingly "harmless to humans and animals" technology being used by equipment manufacturers?
The answer is simple.
First of all, the massive PCDN traffic has put tremendous pressure on the backbone transmission network of operators. Users' broadband is paid on a monthly basis, not by traffic. The more it is used, the greater the pressure on the operator's network, and the key is not to collect more money. Secondly, service providers need to rent the operator's computer room and bandwidth to build a conventional CDN service node. Now that service providers are using PCDN, resource leasing has been greatly reduced, which has affected the profitability of operators. Touching the core interests, the operator must of course **. So, there are those things at the beginning of the article. Operator PCDN is nothing new, it has been done before. This time, it has risen to such a high level of attention, and it is estimated that it was forced to be urgent. **PCDN difficulty
*PCDN, not an easy thing to do.
The data transmitted by PCDN is also business data such as **. It is challenging to distinguish whether a user's data is a PCDN service.
If the distinction is inaccurate or a "one-size-fits-all" approach is adopted, it will definitely affect the normal uplink needs of users (such as camera data, live streaming data, game data, etc.), which in turn will lead to large-scale complaints and even user churn.
In recent years, operators have generally begun to use DPI (Deep Packet Inspection) traffic identification and QoS restrictions to identify and suppress PCDN.
For example, PCDN services can be effectively stifled by accurately identifying PCDN services, ensuring that normal uplink traffic is not affected and PCDN traffic is 15% to 20% packet loss.
However, there are also certain differences in the technical level and effect of different operators.
You may ask, can operators sue content service providers directly? Let them shut down the PCDN business?
There is a certain difficulty in this. Content service providers basically have CDN licenses. PCDN is also a CDN, and theoretically it seems to be a legal business. Regarding PCDN, there is currently a bit of ambiguity and clarity in the relevant regulations.
PCDN is a game between operators and Internet content service providers. So, for us ordinary users, should we use PCDN or not?
Xiao Zaojun personally believes that technology itself is innocent. PCDN is a very good decentralized concept, which has a certain effect on improving the user business experience. For content service providers, it can reduce the burden on servers and reduce bandwidth costs. This is also the return of real gold, and there is no reason not to promote it. However, if regulation is not in place, PCDN introduces some risks and challenges. First, there are security risks. The terminal becomes a PCDN node and interacts with other devices. This can lead to the leakage of private data, or create security breaches and malicious attacks. Secondly, there is the legal risk. The PCDN of regular companies will be strictly controlled, and the transmitted data is normal legal data. However, some companies with unclean hands and feet will implant PCDN in the APP to disseminate illegal content, such as pirated, reactionary, and terrorist audio and video products. This not only harms society, but also leads to the involvement of ordinary users in legal disputes. Third, there is the issue of cost. Is it cost-effective to collect wool through PCDN?
It depends. If the equipment is turned on for a long time, it will lead to the waste of electrical energy. If it's a router running PCDN, it's slightly better. However, PCDN services will cause higher power consumption and greater heat generation of routers, which will still lead to an increase in electricity costs.
PCDN transmits data, which needs to be read and written repeatedly to the storage. This will affect the life of the hard drive, or even the life of the entire device. Final wordsIt is an inevitable trend for operators to carry out the first PCDN. At present, ** business traffic accounts for more than 70% of the total Internet traffic. If the development of PCDN is allowed to go, it will lead to a serious loss of revenue for operators. However, a simple and crude way is also not advisable. **The basic premise of PCDN is that it will not affect the user's normal Internet experience. If it is one-size-fits-all, it is obviously unfair to users to let users "prove their innocence", or in other words, let the installation and maintenance master come to the door to "collect evidence". Nowadays, many PCDN applications, users do not understand, belong to "passive" binding, so how should the responsibility be calculated? Let the user take the blame? If it's too rude, the user will be disgusted. In the end, it is the operators' own user satisfaction and market share that will be eaten up. In order to finally solve this problem, on the one hand, it is necessary to improve the relevant regulations and clarify responsibilities and rights. On the other hand, we will strengthen technology research and development, and introduce deep traffic recognition technologies such as AI neural networks to reduce "accidental injuries".
It is hoped that the problem of PCDN can be solved as soon as possible, so that the technology can return to the essence of serving the public.