Hybrid of client-server and P2P Skype Internet telephony app Finding address of remote party:centralized server(s) Client-client connection is direct(not through server) Instant messaging Chatting between two users is P2P *Presence detection/location centralized: User registers its IP address with central server when it comes online User contacts central server to find IP addresses of buddies 2:Application Layer 10 2: Application Layer 10 Hybrid of client-server and P2P Skype ❖ Internet telephony app ❖ Finding address of remote party: centralized server(s) ❖ Client-client connection is direct (not through server) Instant messaging ❖ Chatting between two users is P2P ❖ Presence detection/location centralized: • User registers its IP address with central server when it comes online • User contacts central server to find IP addresses of buddies