I was very puzzled, when P2P fire it? Or by durability hearts of the doubt, the opportunity to finally girlfriend, brothers already waiting for me at the pool hall, no matter Zeyang first wave of performance.
What is P2P
Are P2P, a Peer-To-Peer, translated as "peer network" or "ad hoc network." P2P is a distributed network, network participants share a portion of hardware resources (processing power, storage capacity, network connectivity, printer, etc.) they have, the resources required to provide these shared services and content by the network, can others on direct access to other nodes (the Peer) without passing through an intermediate entity. In this network of participants in both resources (services and content) provider (Server), and resources (services and content) acquirer (Client).
Before introducing peer network network, we take a look at the traditional Client / Server (C / S) mode is like.
In the traditional C / S mode, we want to download a movie 20G, we need to find a website that offers movie resource, then the server connection download site continuously. That is, from the original location to start downloading this file 20G full data.
In this method, what are the disadvantages?
1, first compare it to rely on server availability , that is, if the server is hung up, then download the movie had to be terminated.
2, if you want to increase the number of downloads of movies, the bandwidth of the site will become a bottleneck , it will lead you download speed decreased, and some even can not be downloaded.
3, because all resources are output by the server, the existence of a single point , if you want to attack someone else is relatively easy, as long as the attack server on it.
It is precisely because the traditional C / S mode there are these pitfalls, P2P is made.
P2P breaks the traditional C / S mode, the status of each node in the network are peers. Each node acts as both a server and provide services to other nodes, but also access to services provided by other nodes.
In P2P mode, if more than one person wants to download the same movie, you can not have to separately download the complete movie 20G from the server.
As a result of P2P mode, each user can act as both a client and can act as a server.
If 4 people at the same 20G download movies, then four people were downloaded each different section, and then another transfer while downloading.
So while we get the data downloaded from the server, while others get the data downloaded from the people there, faster than a single download from the server.
Girlfriend heart OS: P2P is not about you, this Zhashui goods that go to the download, is it I start first from the fast broadcast it? True Otaku! Regardless, the first to go along with it.
The advantage of P2P
An important goal is to make all the P2P network clients can provide resources, including bandwidth, storage space and computing power.
Thus, when a node joins the system and a request for an increase in the capacity of the entire system also increases. This is a structure having a fixed set CS server can not be achieved.
Therefore, P2P structure, the client increase means that all users of slower data transmission.
Besides increasing the speed, P2P technology has the following advantages:
Non-center : network resources and services spread over all the nodes, transmission and implementation of the service information between nodes are carried out directly, without the intervention of intermediate links and can server, avoiding possible bottlenecks. Decentralization of the basic characteristics of P2P, which brings advantages in terms of scalability, robustness, and the like.
Scalability : In the P2P network, as users are added, not only the demand for services has increased, overall system resources and service capacity has expanded synchronously, always be able to more easily meet the needs of users. The whole system is fully distributed, there is no bottleneck. Theoretically its scalability can be considered almost infinite.
Robustness : P2P architecture is inherently resistant to attack advantages, high fault tolerance. Since the service is decentralized among each node, part of a network node or be affected little damage to other parts. Usually P2P network can automatically adjust the overall topology partial node fails, maintaining connectivity to other nodes. P2P networks are usually in a self-organized set up, and allows nodes to freely join and leave. P2P network also can continue to do adaptive accommodate changes in network bandwidth, the number of nodes, load and the like.
Cost-effective : the performance advantages of P2P is an important reason to be widespread concern. With the development of hardware technology, computing and storage capacity and network bandwidth performance personal computer growth in accordance with Moore's law. Using P2P architecture can effectively use a large number of ordinary nodes spread of the Internet, will be distributed computing tasks or stored information to all nodes. Wherein using the computing power of idle or storage space, the purpose of the mass storage and high performance computing. By using a large number of free resources in the network, we can provide greater computational and storage capacity at lower cost.
Privacy : In the P2P network, due to the possibility of transmission of information dispersed among nodes without going through a centralized link, the user's private information to be tapped greatly reduced and leakage. In addition, to address Internet privacy issues are currently the main method of relaying the use of technology, so the participants to communicate hidden among the many network entities. In some of the traditional anonymous communication systems, to achieve this mechanism relies on certain relay server node. In P2P, all participants can provide relay forwarding function, thus greatly improving the flexibility and reliability of anonymous communications can provide better privacy protection for users.
Load Balancing : under P2P network environment because each node is both a server and a client, reduces the need for traditional C / S server computing power, storage capacity of the structure, and because the resources distributed across multiple nodes to achieve a better overall network load balancing.
However, P2P technology is not without drawbacks. P2P technology compared to conventional C / S structure has the following two disadvantages:
Architecture is more complex , in addition to customer service must be developed end, it requires a dedicated terminal.
Used in large-scale network, share disorders, difficult to manage, less secure resources .
Girlfriend heart OS: I am the one God, this is what to say? ? ? Gnaw away the feeling of getting more and more of it, I have to pull it back.
Classification of P2P
The degree of centralized, P2P P2P type can be divided into general, special hybrid type P2P and P2P
P2P applications
Currently, P2P network computing technology is constantly applied to the military, commercial, government, telecommunications, communications and other fields. Depending on the particular application, P2P applications can be roughly classified into the following types:
1, file sharing and downloading content , such as Napster, Gnutella, eDonkey, eMule, Maze, BT , etc., users can install directly from the download or upload files Renyiyitai similar software on the PC, and retrieve, copy the file sharing.
2, computing power and memory sharing , e.g. SETI @ home, Avaki, Popular Power , Netbatch, Farsite the like, may be used to distribute objects stored on network storage or use its idle time for collaborative computing.
3, based on co-processing with shared services platform P2P technology , such as JXTA, Magi, Groove, etc., can be used for business management.
4, instant messaging , including ICQ, QQ, Yahoo Messenger, MSN Messenger , etc., multiple users can communicate via text, voice or file, you can even communicate with the phone.
5, P2P communication and information sharing , such as Skype, Crowds, Onion Routing and so on.
6, based on P2P technology network television and online games , such as boiling point, PPStream, PPLive, QQLive, SopCast, etc., many of today's online games is through peer to peer network approach to achieve.
Girlfriend heart OS: This stock is in play the fool with me or really stupid? I also do not believe that the direct pick and clear talk.
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