We burrow in more profound into the operations of a switch in the CCNP SWITCH Official Certification Direct. The CAM table is one of the elemental operations of a switch. It's not as it were vital for the 642-813 SWITCH exam but it's imperative to know for working on the job. The CAM table, or substance addressable memory table, is display in all Cisco Catalysts for layer 2 exchanging. It is utilized to record a stations mac address and it's comparing switch harbour location. In expansion, a timestamp for the passage is recorded and it's VLAN assignment. The CAM table is utilized in multilayer exchanging for the reason of rapidly exchanging outlines to their goal. The switch looks at the approaching frame's source MAC address and enters it into the CAM table and keeps it there for 300 seconds before maturing out. This can be the default value. If the gadget associated to that switchport is moved to another harbour, the switch records the approaching source MAC address, upgrades the CAM table and evacuates it's past entry for the same MAC address.

Host A is connected to switch port 1 and Host B is connected to switch port 2.

- Host A sends traffic to the switch.

- Host A decides to communicate with Host B.

- 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 switchport 1, has the MAC address of AAAA, VLAND ID of 1, and the timestamp.

- Host B has not communicated with the switch yet.

- When 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.

- 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.

- Host B responds to the unicast frame.

- The switch records the incoming frame from Host B and records Host B's MAC, switchport location, VLAN ID, and applies a timestamp.

- 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.

 
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