> For the complete documentation index, see [llms.txt](https://mirror-networking.gitbook.io/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mirror-networking.gitbook.io/docs/manual/transports/kcp-transport.md). # KCP Transport **KCP transport for Mirror.** kcp2k is the new default Transport for Mirror. ![The KCP Transport component in the Inspector window](/files/-Mejek-K3_H83FB3r2Xr) ### About this transport Why KCP: * 100% C#. * Works on all platforms except WebGL. * Heavy test coverage (83.5%). * Extremely fast. * Extremely simple. * Nearly allocation free\*. "KCP is a fast and reliable protocol that can achieve the transmission effect of a reduction of the average latency by 30% to 40% and reduction of the maximum delay by a factor of three, at the cost of 10% to 20% more bandwidth wasted than TCP. It is implemented by using the pure algorithm, and is not responsible for the sending and receiving of the underlying protocol (such as UDP), requiring the users to define their own transmission mode for the underlying data packet, and provide it to KCP in the way of callback. Even the clock needs to be passed in from the outside, without any internal system calls." We are very excited about KCP and highly recommend trying it in your project. => Previously we had pure C# transports that were slow => And native C transports that were fast, but hard to maintain. KCP brings us the best of both worlds: it's as fast as our native C transports, while still being easy to maintain because it's 100% pure C#! ### Usage Add the KCP Transport component to your NetworkManager. Unblock UDP (not TCP), Port 7777 (the default, unless you change it). ### Credits skywind3000 for original kcp.c () kcp-csharp for first C# port () paul/lymdum/uwee for connection handling. --- # 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://mirror-networking.gitbook.io/docs/manual/transports/kcp-transport.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.