Reaching to an end-system
Reaching to an end-system We are all familiar with the domain name and the IP addressing, when we access any website on internet we call by its name called “domain name”, the domain name is then converted to IP address for accessing that system. But IP address alone is not sufficient; we also need the physical address (MAC address) of the system. As it is not possible for a source system to know the physical address of all the destinations, the Address Resolution Protocol (ARP) was developed to enable communications on an internetwork. Layer 3 devices need ARP to map IP network addresses to MAC hardware addresses so that IP packets can be sent across networks. Before a device sends a datagram to another device, it looks in its ARP cache to see if there is a MAC address and corresponding IP address for the destination device. If there is no entry, the source device sends a broadcast message to every device on the network. Each device compares the IP address to its own. Only the