The MTU (Maximum Transmission Unit) range typically starts at a very small number and extends up to the maximum practical value, but the most relevant value is often the maximum MTU size. In practice, the MTU is configurable, and while there isn't a strict range that applies to all situations, we can discuss practical limits.
Here's a breakdown:
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Theoretical Minimum: The absolute smallest MTU allowed by the IPv4 standard is 68 bytes. For IPv6, it's 1280 bytes.
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Practical Minimum (for Ethernet): While smaller sizes are technically possible, Ethernet networks require a minimum frame size, which influences the practical lower limit of useful MTU values.
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Standard Ethernet Maximum: 1,500 bytes is the most common maximum MTU size for standard Ethernet networks. This is the value most often associated with MTU.
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Jumbo Frames: In specific, controlled environments, such as within a data center, "Jumbo Frames" can be used. These allow for MTUs as large as 9,000 bytes or more.
Therefore, while a precise range isn't generally discussed, think of MTU in terms of the following:
- Typical Ethernet Networks: Aim for 1,500 bytes.
- Specialized Environments (Jumbo Frames): Use up to 9,000 bytes (or greater if supported).
It's more about understanding the maximum that can be supported across your network path than defining a specific "range." Mismatched MTU settings across devices can cause connectivity problems, requiring fragmentation or packet drops. Path MTU Discovery (PMTUD) is a mechanism used to determine the largest MTU supported between two hosts.
