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What is the difference between a mac address table and an arp table? Is it correct to say only one arp cache is kept for each switch which self learns to forward information to another host, and every host on the network has its own mac table, which records the mac address of hosts it wants to send frames to, this information is stored after a broadcast which lead to a host replying with its mac address and mac addresses are removed if unused after 20 minuets to avoid filling up the mac address table.

I just dont know why an arp table /cache differs to a mac table.

Any explanations would be much appreciated.

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A MAC table maps Ethernet hardware addresses to switch ports. An ARP table maps IP addresses to Ethernet hardware addresses. – David Schwartz Apr 27 '13 at 10:38
up vote 4 down vote accepted

MAC Table (Layer 2)

The MAC table is used by the switch to map MAC Addresses to a specific interface on the switch. These usually expire every 5 minutes or so, and are updated by reading the source address of the frame entering the interface. Your switch should have a MAC/CAM Table as a layer 2 device.

ARP Table (Layer 3)

The ARP table is used to map MAC Addresses to IP addresses. If no ARP entry exists, an ARP broadcast is sent out, and the table is updated with the response. These usually expire after 2-4 hours. Each host connected to the network should maintain its own ARP Table.

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so how many mac/arp tables are there? in one network with one switch? – user171131 Apr 27 '13 at 8:59
@user171131: One MAC table in the switch and an ARP table in each TCP/IP client. – Sven Apr 27 '13 at 9:02
Correct! Updated answer to reflect the difference. – David Houde Apr 27 '13 at 9:04

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