lecture2: Classful and Classless Addressing

IPv4 Network layer Classfull and Classless Addressing
This talk will cover the basics of IP addressing and subnetting.
Topics covered will include:
• What is an IP Address?
• What are Classes?
• What is a Network Address?
• What are Subnet Masks and Subnet Addresses?
• How are Subnet Masks defined and used?
• How can all this be applied?
• What is CIDR?
The Network Layer (layer 3)
The network layer is responsible for the source-to-destination delivery of a packet, possibly across multiple networks (links). It ensures that each packet gets from its point of origin to its final destination. If two systems are connected to the same link, there is usually no need for a network layer.
In other word The Network layer is responsible for routing the packet based on its logical address. It also fragments and reassembles packets if necessary.
Internet Protocol ( IP ) Addresses (Logical Address)
What is IP Addressing?
Every host on a network needs to have a unique address, similar to you needing a unique address for your house. With this unique address, it is possible to send data from host to host. Every packet contains addressing information in the header, and the IP address in the header is used to route packets. If several people on your street had the same address, the post office would have a difficult time