i
Search icon

CCNA

Self Learning   /   Study Material   /   Frame Tagging
Previous
Next

Frame Tagging

To identify the VLAN a packet is belonging to, switches use tagging to assign a numerical value to each frame in a network with various VLANs. This is done to assure that switches know out which ports to forward frames.

For an instance, consider the following network topology.

 

 

There are two VLANs in the toplogy shown above, namely VLAN 3 and VLAN 4. Host A sends a broadcast packet to switch SW1. Switch SW1 accepts the packet, tags the packet with the VLAN ID of 3 and sends it to SW2. SW2 accpets the packet, looks up at the VLAN ID, and forwards the packet only out the port Fa0/1, since only that port is in VLAN 3. Host B and host C will not receive the packet because they are in distinct VLAN than host A.

 

© All rights Reserved | SelfLearning.io