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Explainer https://github.com/w3c/webtransport/blob/main/explainer.md Specification https://w3c.github.io/webtransport https://datatracker.ietf.org/doc/html/draft-ietf-webtrans-http3/ https://datatracker.ietf.org/doc/html/draft-ietf-quic-datagram/ Design docs https://web.dev/webtransport/ https://docs.google.com/document/d/1UgviRBnZkMUq4OKcsAJvIQFX6UCXeCbOtX_wMgwD_es/edit Summary WebTransport is an interface representing a set of reliable/unreliable streams to a server. The interface potentially supports multiple protocols, but based on discussions on the IETF webtrans working group, we are developing WebTransport over HTTP/3 which uses HTTP3 as the underlying protocol. This time, we want to ship the core part. The following features are excluded: - Connection sharing - Stream Prioritization - Statistics - WebTransport over HTTP/2 Blink component Blink>Network>WebTransport TAG review https://github.com/w3ctag/design-reviews/issues/669 TAG review status Pending Risks Interoperability and Compatibility This is a new API and doesn’t change any existing behaviors. Gecko: Worth Prototyping <https://github.com/mozilla/standards-positions/issues/167>. They are actively involved in the specification effort. WebKit: No signal <https://lists.webkit.org/pipermail/webkit-dev/2021-September/031980.html>. Web developers: Positive Twitch https://twitch.tv Twitch is using WebTransport to serve live video to our users with lower latency and higher quality. We plan on rolling out our new playback experience once it's fully available given our positive results. WebTransport offers all of the benefits of QUIC, but in a browser environment and without the constraints of HTTP semantics. Most notably we can push data over multiple streams, eliminating head-of-line blocking and enabling new functionality during congestion. This is not possible with existing browser standards such as WebSockets and WebRTC data channels. Google Stadia https://stadia.google.com/ “Google Stadia is using the WebTransport API in conjunction with the WebCodecs API for several use cases, both internally and with partners. The underlying WebTransport protocol, QUIC, has far greater throughput and resiliency characteristics than other mechanisms available, which enables use cases like webcams, and transmission of results of browser-based processing to applications and games in the cloud. The capability to transmit datagrams to cloud endpoints enables many new use cases for Stadia including communication with custom hardware endpoints. In the future we hope to explore using this API for other use cases.” Ergonomics The API is built around ReadableStream/WritableStream interfaces, which means that its core I/O principles would be familiar to the developers who had already used Streams via Fetch and other APIs. The API does not use cookies, HTTP authentication or socket pooling. This would help us avoid unexpected interactions with the other elements of the network stack. Activation Since UDP is often blocked on the network, the developers have to assume that the API often would not work even in the situations when it is implemented in the browser. Security See <https://wicg.github.io/web-transport/#privacy-security> for more info. We allow web developers to use an alternative certification verification method than the usual HTTPS way. We allow a web developer to connect to a WebTransport over HTTP/3 server when its certificate’s fingerprint matches with the developer provided fingerprint. This is discussed at https://github.com/w3c/webtransport/issues/349 and we will update the spec shortly. Debuggability Printing an error message with the reason when the opening handshake fails. We show outgoing WebTransport sessions in the “Network” section of DevTools, the same place where WebSocket connections are shown. Unlike WebSockets, we do not intend to show the actual contents of the WebTransport sessions, thus avoiding the performance decrease that would cause. Just like with regular HTTP/3-based QUIC traffic, detailed information about the connection can be obtained via chrome://net-export interface. Is this feature fully tested by web-platform-tests? Yes We are writing WPTs (/webtransport <https://wpt.fyi/results/webtransport?label=experimental&label=master&aligned>). We expect the task to be completed by the branch point. The WebTransport over HTTP/3 server for testing <https://github.com/web-platform-tests/wpt/tree/master/tools/webtransport> is running locally, but we need more time to run it on wpt.live or Chromium CI. Requires code in //chrome? False Tracking bug https://crbug.com/10111392 Link to entry on the Chrome Platform Status https://chromestatus.com/feature/4854144902889472 -- You received this message because you are subscribed to the Google Groups "blink-dev" group. To unsubscribe from this group and stop receiving emails from it, send an email to blink-dev+unsubscr...@chromium.org. To view this discussion on the web visit https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CABihn6HZaCbG_q8wVv0ukaGRwir-%2BVr0yQTGy3nXH0Qwa1fe%3Dg%40mail.gmail.com.
