Chair of Network Architectures and Services Department of Informatics Technical University of Munich How Good Is QUIC Actually? Manuel Burghard Friday 12 th July, 2019 Chair of Network Architectures and Services Department of Informatics Technical University of Munich
Chair of Network Architectures and Services Department of Informatics Technical University of Munich Outline What is QUIC? Weaknesses and Strengths Performance Conclusion M. Burghard — QUIC 2
What is QUIC? • New transport protocol • Built on top of UDP • Connection oriented & stream multiplexing • Always-on encryption • In standardization by IETF since 2016 • Finalization scheduled for July 2019 M. Burghard — QUIC 3
What is QUIC? Key Goals of QUIC • Minimize connection establishment and transport latency • Multiplexing without head-of-line blocking • Secure the transported payload using TLS 1.3 • Enable deployment without requiring changes along the path • Enable extensions for forward error correction and multipath M. Burghard — QUIC 4
Weaknesses and Strengths Forward Error Correction and Multipath • Multipath: Not part of July milestone • Multipath: Scheduled for late 2019 / early 2020 • Forward Error Correction: Out of scope of initial draft • Was implemented by Google, but removed in 2016 M. Burghard — QUIC 5
Weaknesses and Strengths Secure Transport Problem • Private businesses • Governments and nations M. Burghard — QUIC 6
Weaknesses and Strengths Secure Transport Problem Solution • Private businesses • Always-on encryption • Governments and nations • Based on TLS 1.3 M. Burghard — QUIC 6
Weaknesses and Strengths Secure Transport Problem Solution • Private businesses • Always-on encryption • Governments and nations • Based on TLS 1.3 Strengths • Improved privacy, integrity, and confi- dentiality for users • Broader adoption of encryption M. Burghard — QUIC 6
Weaknesses and Strengths Secure Transport Problem Solution • Private businesses • Always-on encryption • Governments and nations • Based on TLS 1.3 Strengths Weaknesses • Improved privacy, integrity, and confi- • Regulatory and Compliance incompati- dentiality for users bility • Broader adoption of encryption • Inherited attack vectors from TLS 1.3 M. Burghard — QUIC 6
Weaknesses and Strengths Enabling Future Changes to QUIC Problem • Ossification of network equipment • Lack of support in operating systems M. Burghard — QUIC 7
Weaknesses and Strengths Enabling Future Changes to QUIC Problem Solution • Ossification of network equipment • UDP as underlying transport protocol • Lack of support in operating systems • Encrypt signaling information • Version negotiation • User space implementation M. Burghard — QUIC 7
Weaknesses and Strengths Enabling Future Changes to QUIC Problem Solution • Ossification of network equipment • UDP as underlying transport protocol • Lack of support in operating systems • Encrypt signaling information • Version negotiation • User space implementation Strengths • UDP support already exists • Bundling with applications • High adoption rate M. Burghard — QUIC 7
Weaknesses and Strengths Enabling Future Changes to QUIC Problem Solution • Ossification of network equipment • UDP as underlying transport protocol • Lack of support in operating systems • Encrypt signaling information • Version negotiation • User space implementation Strengths Weaknesses • UDP support already exists • UDP blocking and filtering • Bundling with applications • High adoption rate M. Burghard — QUIC 7
Weaknesses and Strengths Head-of-Line Blocking Problem • Packets/requests blocked by item ahead • HTTP/2 prone to TCP HOL blocking M. Burghard — QUIC 8
Weaknesses and Strengths Head-of-Line Blocking HTTP 1.1 TCP connection HTTP 2 QUIC connection HTTP 3 M. Burghard — QUIC 9
Weaknesses and Strengths Head-of-Line Blocking Problem Solution • Packets/requests blocked by item ahead • Loss detection and recovery imple- mented by QUIC itself • HTTP/2 prone to TCP HOL blocking • Uninvolved streams not affected • Retransmission of required packets only M. Burghard — QUIC 10
Weaknesses and Strengths Head-of-Line Blocking Problem Solution • Packets/requests blocked by item ahead • Loss detection and recovery imple- mented by QUIC itself • HTTP/2 prone to TCP HOL blocking • Uninvolved streams not affected • Retransmission of required packets only Strengths • Better performance M. Burghard — QUIC 10
Weaknesses and Strengths Head-of-Line Blocking Problem Solution • Packets/requests blocked by item ahead • Loss detection and recovery imple- mented by QUIC itself • HTTP/2 prone to TCP HOL blocking • Uninvolved streams not affected • Retransmission of required packets only Strengths Weaknesses • Better performance • Reimplementation of loss detection and recovery • Packet reordering M. Burghard — QUIC 10
Weaknesses and Strengths Connection Establishment and Latency Problem • TCP and TLS handshake delay applica- tion data • High latency environments • Poor user experience M. Burghard — QUIC 11
Weaknesses and Strengths Connection Establishment and Latency Problem Solution • TCP and TLS handshake delay applica- • Combined transport and cryptographic tion data handshake (1-RTT) • High latency environments • 0-RTT support • Poor user experience M. Burghard — QUIC 11
Weaknesses and Strengths Connection Establishment and Latency Problem Solution • TCP and TLS handshake delay applica- • Combined transport and cryptographic tion data handshake (1-RTT) • High latency environments • 0-RTT support • Poor user experience Strengths • Handshake latency halved or better M. Burghard — QUIC 11
Weaknesses and Strengths Connection Establishment and Latency Problem Solution • TCP and TLS handshake delay applica- • Combined transport and cryptographic tion data handshake (1-RTT) • High latency environments • 0-RTT support • Poor user experience Strengths Weaknesses • Handshake latency halved or better • 0-RTT support for HTTP/2 with TLS 1.3 M. Burghard — QUIC 11
Weaknesses and Strengths Connection Establishment and Latency Client Server Client Server Client Server Complete CHLO SYN Inchoate CHLO Encrypted Request SYN ACK REJ SHLO Complete CHLO Encrypted Response ACK Encrypted Request CH SHLO SH;CERT;SHD Encrypted Response CKE;CCS;F CCS;F (a) TCP and TLS handshake (b) QUIC 1-RTT connection (c) QUIC 0-RTT connection establishment establishment Abbreviations used in the diagrams: ClientHello (CH, CHLO), ServerHello (SH, SHLO), Certificate (CERT), ServerHelloDone (SHD), ClientKeyExchange (CKE), ChangeCipherSpec (CCS), Finished (F) M. Burghard — QUIC 12
Performance QUIC vs TCP Results observed by multiple authors • QUIC outperforms TCP in high delay, low bandwidth, and lossy networks • Gains on desktop higher than on mobile • TCP superior when packet reordering is required M. Burghard — QUIC 13
Performance QUIC vs TCP Results observed by multiple authors • QUIC outperforms TCP in high delay, low bandwidth, and lossy networks • Gains on desktop higher than on mobile • TCP superior when packet reordering is required Other findings • Higher CPU usage • Poor choice of default parameters of Google’s QUIC server • Unfair bottleneck bandwidth consumption by QUIC • Websites hosted on smaller number of servers performs better M. Burghard — QUIC 13
Conclusion • Design combines benefits of multiple protocols • Strengths outweigh weaknesses • QUIC suited to take over area of high delay, low bandwidth, and lossy networks M. Burghard — QUIC 14
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