ARP and It is Type:

ARP:

Abbreviations :  Address Resolution Protocol:

It operates between Data link layer and Network Layer.

ARP main function is matching network devices MAC address with it's allocated IP address.
This helps other devices to find MAC address based on IP. This way communication between the devices is fast and easy.

Limitations:

It mainly works on a single sub net. It a packet wants to go out of the network they uses the gateway's MAC address as a source .


Types:

1. Reverse ARP.

It act in reverce way of actual ARP.

It Maps MAC addres to IP address  .It  ask its IP  to others and Maps ot.. 

This RARP is been replaced by DHCP now a days .. 

2. Proxy ARP.
3. Inverse ARP.
4. Gratuitous ARP.




Gratuitous ARP:

When machines started to communication they need to establish ARP process to establish the connections between them.

If we enable Gratuitous ARP on the switch ports, It prevent switch from mapping IP address from fake MAC address during ARP process.