> For the complete documentation index, see [llms.txt](https://docs.eseye.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.eseye.com/anynet-sim/connectivity/ip-addressing-and-routing/about-the-maximum-transmission-unit.md). # About the maximum transmission unit The maximum transmission unit (MTU) is a network configuration parameter that restricts the size of the largest data packet or frame size that network devices (such as routers, switches, or network interface cards) can transmit over a network in a single transmission. It is typically configured individually on each network device participating in the network. When two network devices communicate with each other, they negotiate the maximum size of the data packets or frames they can exchange, based on their configured MTU values. This reduces the risk fragmentation or other issues during data transmission. The default MTU can vary depending on the network technology, operating system or device using the network. For Ethernet-based networks (including wired Ethernet and WiFi) the standard MTU setting is 1500 bytes. However, for cellular networks this value may be lower because of the following: * Radio link efficiency: Cellular networks rely on wireless radio links to transmit data. The radio channel introduces certain overhead and limitations, such as signal interference and signal propagation characteristics. Lowering the MTU may optimise data transmission efficiency and reduce the risk of errors or retransmissions. * Network overhead: Cellular networks often have additional protocol overhead compared to wired networks, including encapsulation, encryption, and various signalling protocols used in wireless communication. A smaller MTU value helps accommodate this additional overhead without exceeding the maximum payload size. For more information about encapsulation, see [the MPLS overview](/anynet-sim/connectivity/section-a-connecting-over-the-mobile-network/section-b-connecting-over-eseyes-mpls-network.md). * Fragmentation and latency: Lowering the MTU can reduce the likelihood of packet fragmentation, which occurs when a packet is larger than the maximum size allowed by a particular network. Fragmentation can introduce latency and inefficiencies in data transmission, so a lower MTU helps mitigate this issue. For more information, see [the latency measurement guide](/anynet-sim/connectivity/monitoring-and-diagnostics/measuring-latency.md). * Network provider specifics: Different network providers may have their own infrastructure, technical requirements, and optimisation strategies. They might have determined that a lower MTU value is optimal for their specific network architecture and performance goals. We recommend consulting the network provider documentation to find out their chosen MTU values. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://docs.eseye.com/anynet-sim/connectivity/ip-addressing-and-routing/about-the-maximum-transmission-unit.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.