1. What is P2P? Two types of P2P Example of hybrid P2P Example of pure P2P P2P network Group C Takaaki hukasawa Saori Endo Kazuhiro Matsumoto Eichrou Miyamoto

2. What is P2P? P2P is communication method which render to communicate computer and computer equally. Specifically it connects between terminals directly mutually and sent an d received data. In addition, P2P in LAN is basically located as a functionality expansion of OS. The advantage of P2P is that the network design is easy and the introduction cost is cheap. On the other hand, fault of P2P is that security and the network offer can not be raised. It is said that the delivery of the file of a large capacity is a substantial cost, and the P2P delivery is attractive as the means to r educe the cost simply. Server based network P2P network

3. P2P with server First, a client PC access to the central server which has a list that has IP address of client computeres. Next the client asks a IP address of another client that has a data that its looking for. Then it can connect to another computere with that IP address. This is called hybrid P2P. Client computer needs IP address to connect to another computer. P2P without server All information and data are transported directly between client computers. They do not need to access to the server for IP address, because it is on the P2P network. This is called pure P2P. Two types of P2P

4. There is Skype as an example of server type P2P. Skype is abbreviation of "Sky peer-to-peer". Skype is Internet phone using the P2P technology service, and it communicates by the following flows. 1. It is registered in the Skype server when Skype is downloaded, and a digital certificate is issued. 2.When you will log node in next time,it is connected with a super-node that is the server of the list of the node logged in. 3. Internet Protocol address of the node is acquired from a super-node, and the node makes the communication possible directly. 4. The packet is transmitted whenever it communicates from the inside of the firewall. Moreover, it relays it with the machine of the third party who has the global address when both are in the firewall. The communication without a complex setting is enabled by this. Example of hybrid P2P

5. Example of pure P2P Pure P2P is hardly break, because it do not depend on one particular path, but can use any path to reach to the computer which it want to connect. Therefore, in Japan, it is used for P2P Earthquake information. P2P earthquake information. All node get earthquake information from a server of Japan Meteorological Agency and share it on the network. Also they can send earthquake information The information can go through any path, so all nodes can get information surely. For example, if one path was disconnected by an accident, data can go through other paths and nodes.