WebRTC is a technology that enables peer-to-peer communication between browsers. It not only supports the transmission of audio and video data but also arbitrary data, which is referred to as the Data Channel.
Regarding the maximum size of WebRTC Data Channel messages, this size is determined by the underlying transport protocol, SCTP (Stream Control Transmission Protocol). SCTP is a protocol that supports multi-stream transmission, with a default Maximum Transmission Unit (MTU) of approximately 1200 bytes. This is to accommodate the minimum MTU values prevalent in most internet environments, thereby reducing the likelihood of packet fragmentation and reassembly, and improving data transmission efficiency.
However, SCTP supports fragmentation and reassembly of transmitted messages, so theoretically, WebRTC Data Channel can support messages of arbitrary size. In practice, the maximum message size may be constrained by application-level limitations or specific implementations. For example, certain browsers may impose their own limits to manage memory usage or ensure performance.
From a practical standpoint, when transmitting large amounts of data, it is recommended to split the data into multiple smaller chunks for transmission, which can enhance transmission stability and efficiency. For instance, when sending a large file via WebRTC Data Channel, the file can be split into multiple chunks of size less than or equal to 1MB and sent sequentially.
In summary, WebRTC Data Channel can support large messages, but for optimizing performance and compatibility, it is generally recommended to split large data into smaller chunks for transmission.