Which header field controls how many routers a packet can pass through before being discarded?

Which header field controls how many routers a packet can pass through before being discarded?

• A. Time to Live (TTL)
• B. Session splicing
• C. Unicode
• D. Fragmentation

Answer: (A)

The main idea is the hop limit carried in the IP header, called Time to Live. At each router that forwards the packet, TTL is decreased by one. When TTL reaches zero, the packet is discarded to prevent it from looping endlessly in the network. This mechanism also makes traceroute possible, by observing the timeouts and the routers that decrement TTL. The other options don’t fit because fragmentation is about splitting packets to fit the network’s MTU, Unicode is just a character encoding, and session splicing is not a standard header field related to how many routers a packet can pass through.

The main idea is the hop limit carried in the IP header, called Time to Live. At each router that forwards the packet, TTL is decreased by one. When TTL reaches zero, the packet is discarded to prevent it from looping endlessly in the network. This mechanism also makes traceroute possible, by observing the timeouts and the routers that decrement TTL. The other options don’t fit because fragmentation is about splitting packets to fit the network’s MTU, Unicode is just a character encoding, and session splicing is not a standard header field related to how many routers a packet can pass through.