To prevent network congestion caused by loops, the IP header includes a TTL field.

The Time to Live (TTL) field is an important component of the IPv4 header. It prevents packets from circulating indefinitely when routing loops occur.

The source device assigns an initial TTL value when generating an IP packet.

Each router forwarding the packet decreases the TTL value by one. If forwarding would reduce the TTL to zero, the router discards the packet and normally generates an ICMP Time Exceeded message.

However, conventional Layer 2 switches do not decrease the IP TTL when forwarding Ethernet frames. Layer 2 forwarding relies primarily on destination MAC addresses and operates below the IP network layer.

Therefore, the statement is incorrect because it claims that both Layer 2 and Layer 3 devices decrease the TTL during forwarding.

Only Layer 3 forwarding decrements the IP TTL under normal circumstances.

The correct answer is FALSE.

================