Managing The Mac Address Tables - Cisco WS C4224V 8FXS - 200Mbps Ethernet Switch Software Configuration Manual

Managing the Catalyst 4224 Access Gateway Switch

Managing the MAC Address Tables

Catalyst 4224 Access Gateway Switch Software Configuration Guide
3-18
The Address Resolution Protocol (ARP) associates a host IP address with
corresponding media or MAC addresses and 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.
When you manually add entries to the ARP Table by using the CLI, you must be
aware that these entries do not age and must be manually removed.
The switch uses the MAC address tables to forward traffic between ports. All
MAC addresses in the address tables are associated with one or more ports. These
MAC tables include the following types of addresses:
• Dynamic address—A source MAC address that the switch learns and then
drops when it is not in use.
Secure address—A manually entered unicast address that is usually
•
associated with a secured port. Secure addresses do not age.
Static address—A manually entered unicast or multicast address that does not
•
age and that is not lost when the switch resets.
The address tables list the destination MAC address and the associated VLAN ID,
module, and port number associated with the address. Figure 3-3 shows an
example of a list of addresses as they would appear in the dynamic, secure, or
static address table.
Chapter 3 Configuring Ethernet Switching
OL-2031-02