# Maximum transmission units (MTUs) in devices ## What is MTU size MTU represents the maximum payload size of a network packet that can be transmitted across a network. It specifies the largest data size that can be encapsulated within a packet and sent from one device to another without being divided into smaller fragments. Maximum transmission unit size is measured in bytes, including the data payload and the packet headers. ## Maximum transmission unit explained When data is transmitted over a network, it is divided into packets for efficient delivery. These packets consist of a header section and a payload section. The header contains control information, such as source and destination addresses, while the payload contains the transmitted data. The MTU size determines the largest packet size that can be transmitted between two networked devices - across all intermediate network components. ## US carriers * AT\&T: 1420 bytes * Verizon: 1428 bytes * T-Mobile: 1420 bytes ## International The recommended MTU size is 1400 bytes, which is internationally compatible with most mobile networks. ## Other common MTU values * LAN connection to LAN client: 1500 bytes * WiMAX wireless WAN connection: 1400 bytes * Cable/DOCSIS modem wired WAN connection: 1500 bytes * DSL modem wired WAN connection: 1492 bytes ## Resources Refer to these resources for additional information. * [Tech tip - What MTU value should I use for my cellular connection?](https://youtu.be/PhvlPTsa2Nw?si=kW4MUbMm_vzOJkWq) * [Cellular network — Importance of MTU on UPF performance & UE connectivity](https://medium.com/@thakur.ajay/impact-of-mtu-on-upf-performance-ue-connectivity-0607345bee46) --- # Agent Instructions: 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: ``` GET https://docs.korewireless.com/omni-sim/omnisim-device-guides/maximum-transmission-units-mtus-in-devices.md?ask= ``` The question should be specific, self-contained, and written in natural language. 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.