This lecture briefly describe on fundamental of Networking and Internetworking. Networking is any connection between two or more computers. A network’s speed can be summed up with two values: Bit rate and Latency. Internetworking is any connection between two or more networks. Here also explain what is Local Area Network (LAN), Important Network Properties, Internet Implementation. here focus on various Schemes for Organizing the Responsibility of Networking Components. Finally explain some Network Service Models.