ARP Request, or Straight from the Table?

About this interactive

From the lesson: - **ARP request:** to send a frame to an IP address on its LAN, a host needs that device's MAC address. If it does not have it, it asks: who has this IP address? The owner replies with its MAC. - **ARP table (ARP cache):** the host stores each answer, the IP address and its MAC, so the next packet to that address needs no request. - **Expiry:** the network changes, so entries expire. A missing entry, an expired one, or a table that has been cleared (the lesson's demo clears it, and it fills again at once) means a new request.

What you'll learn

Decide whether a host can take a destination's MAC address from its ARP table or must send an ARP request first
Recognize that ARP table entries are cached from earlier replies and expire, so a missing, expired or cleared entry means a new request

Aligned to

CompTIA Network+

1.1 Explain concepts related to the Open Systems Interconnection (OSI) reference model.

Cisco CCST Networking

1.1 Identify the fundamental conceptual building blocks of networks

Key terms

ARP Table: A cache stored on a device that holds mappings of IP addresses to MAC addresses, reducing the need for repetitive ARP broadcasts.
Address Resolution Protocol: A protocol used to map an IP address to a physical MAC address on a local network.
ARP Cache: A temporary table stored in memory that holds recent IP-to-MAC address mappings discovered through ARP.
MAC Address: A 48-bit hardware address assigned to a network interface and written as six hexadecimal octets, such as 00:1A:2B:3C:4D:5E. It identifies a device uniquely on a local network segment, and switches forward frames by looking it up in their MAC address table.
IP Address: A numerical label assigned to each device connected to a network that uses the Internet Protocol.

Topics

Arp Arp Table Arp Cache Mac Address Ip Address Interactive Streak Sort

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