Shulou(Shulou.com)06/01 Report--

This article will explain in detail what the QUIC protocol means. The content of the article is of high quality, so the editor will share it for you as a reference. I hope you will have some understanding of the relevant knowledge after reading this article.

The full name of QUIC is Quick UDP Internet Connections protocol, which is proposed by Google. At present, it is driven by the IETF working group. The goal of its design is to replace TCP to become the data transport layer protocol of HTTP/3. Xile Technology in the Internet of things (IoT) and edge computing (Edge Computing) scenarios has been building the underlying edge computing micro-service framework YoMo based on QUIC communication protocol, and pays close attention to the development of QUIC protocol for a long time. This article briefly introduces the characteristics and terminology of QUIC protocol.

QUIC is a universal multiplexing and secure transport protocol that provides:

Stream (stream) multiplexing

Flow control at the stream and connection levels

Establish a low-latency connection (1-RTT or 0-RTT)

Connection migration (Connection migration) and elastic NAT rebinding

Authenticated and encrypted header (header) and payload (payload)

QUIC establishes a stateful interactive connection between the client (client) and the server (server). The main purpose of the connection is to support structured data exchange through application protocols.

The application protocol exchanges information through a QUIC-connected stream (streams), which is an ordered sequence of bytes (bytes). The stream is an ordered sequence of bytes (bytes). Two types of flows can be created: two-way flows (bidirectional streams) that allow clients and servers to send data to each other. Unidirectional flow (unidirectional streams), which allows a single endpoint (endpoint) to send data. A credit-based scheme (credit-based scheme) is used to limit the creation of streams and the amount of data that can be sent.

The streams in a QUIC connection is independent of each other. If packet loss occurs in a stream (stream), it will not affect other streams that are normally transmitted in the connection. This avoids head of line blocking (Head-of-Line blocking) in the TCP protocol.

QUIC handshake (handshake) combines encryption and negotiation of transmission parameters, which only requires 1-RTT to complete the handshake, increasing the speed of establishing a connection to the exchange application data. On the second connection, the data (0-RTT) can be sent immediately through the pre-shared key (pre-shared secret) obtained on the first connection.

QUIC connections are not strictly bound to a single network path (IP:Port). Connection Migration (Connection migration) uses a connection ID to allow connections to be transferred to a new network path. For example, when the mobile phone network is switched from cellular to WIFI, the IP address changes, and QUIC can avoid connection interruption through connection migration (connection migration).

QUIC uses frames (frames) for end-to-end communication. One or more frames (frame) are assembled into a QUIC packet (packet). QUIC authenticates all packets and encrypts them as much as possible, increasing the security of end-to-end transmission. QUIC packets are transmitted by UDP Datagram (datagrams) instead of creating a new transport layer protocol. This is because existing network equipment and systems support TCP and UDP protocols, and TCP has shortcomings such as head-of-line blocking, so UDP has become the protocol of choice for QUIC, which can be deployed more quickly in existing systems and networks. QUIC is in user space (user space), which can be updated iteratively faster than TCP (kernel space, operating system kernel).

After a connection is established, you can close the connection with several options: the application can manage normal (graceful) closure, the endpoint (endpoints) can negotiate a timeout, errors can cause immediate disconnection, and statelessness (the stateless mechanism provides the ability to terminate a connection after an endpoint loses state.

Common terms of QUIC protocol:

Packet: a complete disposable unit of the QUIC protocol that can be encapsulated in a UDP Datagram (datagram). Multiple QUIC packets (packets) can be encapsulated in a single UDP Datagram (datagram).

Frame (Frame): the payload (payload) of the QUIC packet (packet).

Endpoint (Endpoint): generates, receives, and processes QUIC packets (packets) in a QUIC connection. There are only two types of endpoints (endpoints) in QUIC: the client (client) and the server (server).

Client (Client): the endpoint that creates the QUIC connection.

Server (Server): the endpoint that receives the QUIC connection.

Address (Address): a tuple that represents the IP version, IP address, and UDP port number at one end of the network path when used without qualification.

Connection ID (Connection ID): an identifier used to identify an endpoint QUIC connection. Each endpoint (endpoint) selects one or more connection ID for its peer (peer) and includes it in a packet (packets) sent to that endpoint. This value is opaque to peer.

Stream: an one-way (unidirectional) or two-way (bidirectional) channel of ordered bytes in a QUIC connection. A QUIC connection can carry multiple streams at the same time.

Application (Application): an entity that uses QUIC to send or receive data.

About what the QUIC agreement means to share here, I hope that the above content can be of some help to you, can learn more knowledge. If you think the article is good, you can share it for more people to see.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.