1. The CAM Table
The CAM table, or content addressable memory table, is present in all Cisco Catalysts for
layer 2 switching. It is used to record a stations mac address and it’s corresponding switch
port location. In addition, a timestamp for the entry is recorded and it’s VLAN assignment.
The CAM table is used in multilayer switching for the purpose of quickly switching frames
to their destination. The switch looks at the incoming frame’s source MAC address and
enters it into the CAM table and keeps it there for 300 seconds before aging out. This is the
default value.

2. 1.Host A is connected to switch port 1 and Host B is connected to switch port
2. Host A sends traffic to the switch.
2. The switch looks into the frame and records the source MAC address (of
Host A) and places an entry into the CAM table. Host A is on switch port 1,
has the MAC address of AAAA, VLAND ID of 1, and the timestamp.
3. Host B has not communicated with the switch yet.
4. Host A decides to communicate with Host B.
5. Host A sends a frame to the switch destined to Host B, the switch notices
the destination MAC address (for Host B) in the frame, queries the CAM table
for that MAC address but doesn’t find it.
6. Because the destination MAC is unknown, the switch marks the frame for
flooding and sends the unicast frame to all ports with the same VLAN
association.
7. Host B responds to the unicast frame.
8. The switch records the incoming frame from Host B and records Host B’s
MAC, switch port location, VLAN ID, and applies a timestamp.
9.The next time Host A sends a frame destined for Host B, the switch queries
it’s CAM table, finds Host B in the table and sends the frame directly to Host
B.
How a CAM table
works