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What is ARP Cache and ARP Table?
ARP (Address Resolution Protocol) is a fundamental protocol used in computer networks to map an IP address to a MAC address. An IP address is the logical address assigned to a device on a network, while a MAC address is the physical address embedded in the network interface card. Communication between devices on a network requires the translation of IP addresses to MAC addresses, and this is where ARP comes into play.
ARP Cache, also known as ARP table or ARP cache table, is a mapping table that stores the association between IP addresses and MAC addresses. It is maintained by the operating system or network devices to facilitate IP address resolution for network communication.
How does ARP Cache work?
When a device needs to communicate with another device on the same network, it first checks its ARP Cache to see if it already knows the MAC address corresponding to the IP address it needs to reach. If the mapping is found in the ARP Cache, it is known as a “cache hit” and the device can proceed with sending the network packet directly to the destination device using the known MAC address.
However, if the mapping is not found in the ARP Cache, it is known as a “cache miss” and the device needs to perform an ARP request. An ARP request is a broadcast message sent to all devices on the network, asking the device with the specific IP address to respond with its MAC address. Once the ARP request is received, the device updates its ARP Cache with the new mapping information. Subsequent communication with the same device requires only a cache hit, avoiding the need for additional ARP requests.
Why is ARP Cache important?
ARP Cache plays a vital role in optimizing network communication. By storing MAC address associations, it eliminates the need for frequent ARP requests, which can cause delays and increase network traffic. The cache allows for faster IP address resolution, improving overall network performance and efficiency.
However, it’s essential to note that ARP Cache entries have a limited lifetime, typically ranging from a few minutes to a few hours. This ensures that outdated mappings are eventually removed from the cache and new ARP requests are sent when needed. ARP Cache poisoning and spoofing attacks can exploit the ARP Cache, leading to malicious actions, so network security measures should be in place to mitigate such risks.
In conclusion, the ARP Cache, also known as the ARP table, is a crucial component of network communication. It stores and updates mappings between IP addresses and MAC addresses, enabling efficient address resolution and reducing the need for frequent ARP requests. Understanding how ARP Cache works helps optimize network performance and maintain network security.
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