Addressing TCP issues with HTTP/3 and QUIC – Understanding Network and Security for Near-Edge Computing

HTTP/3 – Hypertext Transfer Protocol version 3

This is the latest revision of the HTTP protocol and is widely used for communication between web browsers and servers. It is based on Quick UDP Internet Connections (QUIC), a transport protocol developed by Google. QUIC is designed to provide a secure and efficient transport layer protocol over the internet.

Upsides of HTTP/3 and QUIC

QUIC, being based on UDP, doesn’t suffer from throughput limitations due to latency or packet loss seen with TCP-based protocols such as HTTP/2. This is its primary benefit as it relates to edge computing – you no longer need to do a bunch of calculations and mitigations to accommodate these factors.

However, there are many other benefits to implementing these newer protocols.

Connection setup latency

In HTTP/2, establishing a connection requires a series of round trips between the client and server, leading to increased latency. QUIC, being built on UDP instead of TCP, significantly reduces connection establishment latency by combining the initial connection setup and encryption handshake into a single step. This helps improve the overall performance and responsiveness of web applications.

Head-of-line blocking

HTTP/2 suffers from head-of-line blocking, where a delay or loss of a single packet affects the delivery of subsequent packets. QUIC resolves this issue by using packet-level parallelism. Each packet in QUIC is treated as an independent unit, enabling concurrent delivery and reducing the impact of packet loss or delay on other packets. This improves overall throughput and minimizes the effect of network congestion.

Packet loss and recovery

TCP, the underlying transport protocol of HTTP/2, relies on congestion control mechanisms that can be overly cautious and slow to recover from packet loss. QUIC includes congestion control algorithms that are specifically designed for the characteristics of modern networks. It uses forward error correction and retransmission mechanisms to recover lost packets more efficiently, resulting in improved reliability and reduced latency.

Security

QUIC integrates encryption by default, providing secure communication between clients and servers. Unlike HTTP/2, which relies on additional protocols such as TLS to establish secure connections, QUIC ensures end-to-end encryption without the need for separate encryption layers. This enhances security and privacy for data transmission over the internet.

Network traversal

QUIC operates at the transport layer and is designed to work seamlessly with modern network infrastructures, including those with Network Address Translation (NAT) and firewalls. It encapsulates the QUIC packets within UDP, making it easier to traverse network boundaries without requiring complex configuration changes. This facilitates faster deployment and adoption of the protocol in various network environments.