Full form: Maximum Transmission Unit
Also known as: Maximum Transmission Unit
Quick Definition
The largest size (in bytes) of a frame or packet that can be sent on a network link.
MTU is the maximum amount of data that can be carried in a single frame or packet on a network link. The standard Ethernet MTU is 1500 bytes. If a packet exceeds the MTU of a link, it must be fragmented (at the IP layer) or the sender must use Path MTU Discovery (PMTUD) to find the correct size. Mismatched MTU settings can cause intermittent connectivity issues — large packets fail while small packets (like ping) succeed.
A common symptom of an MTU mismatch is that small pings succeed but large file transfers fail. This is a classic CCNA troubleshooting scenario.
MTU is the maximum amount of data that can be carried in a single frame or packet on a network link. The standard Ethernet MTU is 1500 bytes. If a packet exceeds the MTU of a link, it must be fragmented (at the IP layer) or the sender must use Path MTU Discovery (PMTUD) to find the correct size. Mismatched MTU settings can cause intermittent connectivity issues — large packets fail while small packets (like ping) succeed.
A common symptom of an MTU mismatch is that small pings succeed but large file transfers fail. This is a classic CCNA troubleshooting scenario.
MTU falls under the Network Fundamentals domain of the 200-301 exam. Understanding it in context with related terms like tcp and icmp is essential for answering scenario-based questions correctly.