Cisco Catalyst 9200 Configuration Manual page 23

Administering the Device
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MAC Address Table
The MAC address table contains address information that the device 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 device 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 device
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, see the command reference
for this release.
MAC Address Table Creation
With multiple MAC addresses supported on all ports, you can connect any port on the device to other network
devices. The device 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 devices are added or
removed from the network, the device 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 device maintains an address table for each VLAN,
and STP can accelerate the aging interval on a per-VLAN basis.
The device sends packets between any combination of ports, based on the destination address of the received
packet. Using the MAC address table, the device 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 device always uses the store-and-forward method: complete packets are stored and checked
for errors before transmission.
MAC Addresses and VLANs
All addresses are associated with a VLAN. An address can exist in more than one VLAN and have different
destinations in each. Unicast addresses, for example, could be forwarded to port 1 in VLAN 1 and ports 9,
10, and 1 in VLAN 5.
Each VLAN maintains its own logical address table. A known address in one VLAN is unknown in another
until it is learned or statically associated with a port in the other VLAN.
MAC Addresses and Device Stacks
The MAC address tables on all stack members are synchronized. At any given time, each stack member has
the same copy of the address tables for each VLAN. When an address ages out, the address is removed from
resets.
System Management Configuration Guide, Cisco IOS XE Gibraltar 16.10.x (Catalyst 9200 Switches)
Default Banner Configuration
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