What is ARP ?
- Its is stands for Address Resolution Protocol.
- ARP associates an IP address with the physical address.
- Use to resolve IP Address to MAC addresses.
- The main Work of the ARP is to convert the 32-bit IP address to 48-bit address.
Mapping of IP Address into Mac Address
- Static Mapping
- Table is create with logical and physical Address.
- Dynamic Mapping
- Each time a machine knows the logical Address of Another machine.
- it can use a protocol to find the physical address
Two Different types of APR Entries
- Dynamic :-
- Dynamic Entry is create automatically when a device sends out a broadcast message out on the network.
- Dynamic Entry are not permanent.
- They are flushed out periodically.
- Static :-
- A static Entry is where someone manually enters an IP to MAC address association using ARP Command line utility.
- A static Entry are often use to reduce any unnecessary ARP broadcast traffic on a network.
The working of ARP protocol
ARP accepts a logical address from the IP protocol, maps the Address to the Corresponding Physical address and pass it to the data link layer.
Anytime a HOST or a Router need to find a physical Address of another Host or Router on its network , it sends an ARP Query Packet. The packet Includes the physical and IP address of the receiver. Query is broadcast to the network, when the intended recipient recognizes its IP address , it sends back an ARP response packet which contains both IP and Physical Address.
ARP Packet Format
To know more about Rom please check Wikipedia link click HERE.
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