Point to Point Architecture

The term  peer means equal which can  be informally  interpreted as a process with  capability similar to the other processes with process communicates. In the context of P2P networks a peer process acts as a client process and at the same  time a server process for the  same functions. For example  a process  that downloads files from other and meanwhile  the process shared files  for others  to download  is a peer process in file downloading uploading. There is  no distinction between  these  processes  in terms  of which  is  providing  or using  services. Peer processes communicate  with each other  in  a symmetric pattern.  Note that the function that a peer process requests and offer  must  by the  same  within  the context of a given applications.

In P2P architecture  there is not an always   on server at the  centre of the applications. Instead arbitrary pairs of hosts called peers communicate directly with  each other because the peers communicate  without  passing through some  special server, the  architecture is called peer to peer. The P2P architecture is illustrated in figure 3.1 (b).

 One of the greatest strengths of the P2P architecture is its scalability. For  example  in a P2P file  sharing application millions of peers may participate  in the file sharing community with each one functioning  as a server and contributing resources  files and also  community. This while  each peer  will generals work load by requesting files, and  also adds serves  capacity to the system sub responding to the requests of other peers. Thus  increases the demand but also increase service capacity on the  other hand because of  the highly  distributed and decentralized nature  of P2P applications they can be difficult  to manage.

                                             figure client Server Application P2P architecture