SCTP packet size probe

Finds the largest WebRTC data-channel (SCTP/DTLS) packet that gets from the server to this browser, and checks whether a large message on an ordered, reliable channel arrives or stalls.

1 · Connect

Browser ICE policy Browser TURN transport Server ICE policy Server TURN transport

idle

2 · Find the largest packet that gets through

Probes go on an unordered channel with maxRetransmits: 0: each probe is exactly one SCTP packet, and a lost one is dropped instead of blocking the connection. Sizes are SCTP user data bytes; the table shows the real UDP payload the server sent.

Min user data Max user data Resolution (bytes) Copies per probe

Sweep step

#	User data	SCTP pkt	UDP payload	IPv4 pkt	IPv6 pkt	Received	Time

3 · Production-like large message

Sends one message on an ordered, reliable channel (like production). The server fragments it into DATA chunks of the given size (aiortc default: 1200). If those packets don't fit the path, aiortc retransmits them forever and the whole connection stalls — you'll need to reconnect afterwards.

Message size (bytes) Server fragment size Timeout (s)

Report

Results are also posted to the server log after each test.