MTU — what is it, and how does it affect the network?

MTU (Maximum Transmission Unit) — the maximum size of a data packet (in bytes) that can be transmitted over a network without fragmentation.

Impact on the network:

• If a packet exceeds the MTU, it is fragmented, which increases delays and processing load.
• An excessively large MTU can lead to packet loss if intermediate equipment does not support such a size.
• A too small MTU reduces transmission efficiency as the proportion of overhead data increases.

For example, the standard MTU for Ethernet is 1500 bytes. If you have a VPN or tunnel, the MTU may be smaller due to additional headers, and this should be considered to avoid fragmentation and performance issues.