Managing The Arp Table - Cisco Catalyst 3750 Software Configuration Manual

Metro switch

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Managing the ARP Table

Commands for Displaying the MAC Address Table (continued)

show mac address-table static

show mac address-table vlan

Managing the ARP Table

To communicate with a device (over Ethernet, for example), the software first must determine the 48-bit

MAC or the local data link address of that device. The process of determining the local data link address

from an IP address is called address resolution.

The Address Resolution Protocol (ARP) associates a host IP address with the corresponding media or

MAC addresses and the VLAN ID. Taking an IP address as input, ARP determines the associated MAC

address. Once a MAC address is determined, the IP-MAC address association is stored in an ARP cache

for rapid retrieval. Then the IP datagram is encapsulated in a link-layer frame and sent over the network.

Encapsulation of IP datagrams and ARP requests and replies on IEEE 802 networks other than Ethernet

is specified by the Subnetwork Access Protocol (SNAP). By default, standard Ethernet-style ARP

encapsulation (represented by the arpa keyword) is enabled on the IP interface.

ARP entries added manually to the table do not age and must be manually removed.

For more information, refer to the Cisco IOS Release 12.1 documentation on Cisco.com.

Catalyst 3750 Metro Switch Software Configuration Guide

Displays only static MAC address table entries.

Displays the MAC address table information for the specified VLAN.

Administering the Switch