ARP (Address Resolution Protocol)
ARP stands for Address Resolution Protocol. ARP is used to convert the logical address ie. IP address into physical address ie. MAC address. While communicating with other nodes, it is necessary to know the MAC address or physical address of the destination node. If any of the node in a network wants to know the physical address of another node in the same network, the host then sends an ARP query packet. This ARP query packet consists of IP address and MAC address of source host and only the IP address of destination host. This ARP packet is then received to every node present in the network. The node with its own IP address recognises it and sends it MAC address to the requesting node. But sending and receiving such packets to know the MAC address of destination node it increases the traffic load. Therefore in order to reduce this traffic and improve the performance, the systems that makes use of ARP maintain a cache of recently acquired IP into MAC address bindings.
How Does ARP Work?
- The host broadcasts an ARP inquiry packet containing the IP address over the network in order to find out the physical address of another computer on its network.
- The ARP packet is received and processed by all hosts on the network; however, only the intended recipient can identify the IP address and reply with the physical address.
- After adding the physical address to the datagram header and cache memory, the host storing the datagram transmits it back to the sender.
ARP
Types of ARP Entries
- Static Entry: This type of entry is created when a user uses the ARP command utility to manually enter the IP to MAC address association.
- Dynamic Entry: A dynamic entry is one that is automatically formed when a sender broadcasts their message to the whole network. Dynamic entries are periodically removed and are not permanent.
Network Layer Protocols
Network Layer is responsible for the transmission of data or communication from one host to another host connected in a network. Rather than describing how data is transferred, it implements the technique for efficient transmission. In order to provide efficient communication protocols are used at the network layer. The data is being grouped into packets or in the case of extremely large data it is divided into smaller sub packets. Each protocol used has specific features and advantages. The below article covers in detail the protocols used at the network layer.