[network planning] 2.1.1 brief introduction to client server system and P2P system

Network application architecture

Two main application architectures ： Customer - Server architecture and P2P Architecture

Customer - Server architecture ： There's a host that's always on called The server , He receives requests from many hosts called clients , And return resources to them . We usually visit the website as a server , And we are one of the clients . There is no direct communication between clients , Instead, they exchange information with each other through servers . At the customer - Server application , Often, a single server host cannot keep up with the request , So , Equipped with a large number of hosts Data Center Often used to create powerful virtual servers . For example, the most popular Internet service , Search engine , There will be many data centers to support .

P2P Architecture ：P2P Minimal dependency on dedicated servers located in the data center . contrary , On different hosts P2P Applications communicate with each other , Such hosts are called peers .P2P It is a decentralized network architecture , Each host is both a client and a server , With P2P Download, for example , Each host receives download resources from different hosts , Also download resources for different host providers , Be similar to “ I help you , You help me ”.P2P The most fascinating thing is their Self expandability , Like in one P2P File sharing applications , Although each peer generates a workload due to the request file , But each peer also adds service capability to the system by distributing files to other peers .