Cisco 3560G 48TS Software Configuration Guide - Page 143
Managing the MAC Address Table
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Chapter 6 Administering the Switch Managing the MAC Address Table Managing the MAC Address Table The MAC address table contains address information that the switch uses to forward traffic between ports. All MAC addresses in the address table are associated with one or more ports. The address table includes these types of addresses: • Dynamic address: a source MAC address that the switch learns and then ages when it is not in use. • Static address: a manually entered unicast address that does not age and that is not lost when the switch resets. The address table lists the destination MAC address, the associated VLAN ID, and port number associated with the address and the type (static or dynamic). Note For complete syntax and usage information for the commands used in this section, refer to the command reference for this release. This section contains this configuration information: • Building the Address Table, page 6-21 • MAC Addresses and VLANs, page 6-22 • Default MAC Address Table Configuration, page 6-22 • Changing the Address Aging Time, page 6-22 • Removing Dynamic Address Entries, page 6-23 • Configuring MAC Address Notification Traps, page 6-23 • Adding and Removing Static Address Entries, page 6-25 • Configuring Unicast MAC Address Filtering, page 6-26 • Displaying Address Table Entries, page 6-28 Building the Address Table With multiple MAC addresses supported on all ports, you can connect any port on the switch to individual workstations, repeaters, switches, routers, or other network devices. The switch provides dynamic addressing by learning the source address of packets it receives on each port and adding the address and its associated port number to the address table. As stations are added or removed from the network, the switch updates the address table, adding new dynamic addresses and aging out those that are not in use. The aging interval is globally configured. However, the switch maintains an address table for each VLAN, and STP can accelerate the aging interval on a per-VLAN basis. The switch sends packets between any combination of ports, based on the destination address of the received packet. Using the MAC address table, the switch forwards the packet only to the port associated with the destination address. If the destination address is on the port that sent the packet, the packet is filtered and not forwarded. The switch always uses the store-and-forward method: complete packets are stored and checked for errors before transmission. 78-16156-01 Catalyst 3560 Switch Software Configuration Guide 6-21
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