From a24b768feff0bc289273e3683f09ab357693a694 Mon Sep 17 00:00:00 2001
From: ID Bot
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Table of Contents
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2. Compression Process Overview¶
-7.1. Probing Dynamic Table State¶
-Appendix B. Encoding and Decoding Examples¶
-4. Relevant Differences Between QUIC and TCP¶
-5. Estimating the Round-Trip Time¶
-6.1. Acknowledgment-Based Detection¶
-7.3. Congestion Control States¶
-Appendix A. Loss Recovery Pseudocode¶
-Appendix B. Congestion Control Pseudocode¶
-8. QUIC-Specific Adjustments to the TLS Handshake¶
-Appendix A. Sample Packet Protection¶
-Appendix B. AEAD Algorithm Analysis¶
-B.1. Analysis of AEAD_AES_128_GCM and AEAD_AES_256_GCM Usage Limits¶
-7. Cryptographic and Transport Handshake¶
-8.1. Address Validation During Connection Establishment¶
-9.3. Responding to Connection Migration¶
-13. Packetization and Reliability¶
-13.2. Generating Acknowledgments¶
-13.4. Explicit Congestion Notification¶
-14.2. Path Maximum Transmission Unit¶
-14.3. Datagram Packetization Layer PMTU Discovery¶
-18. Transport Parameter Encoding¶
-21.1. Overview of Security Properties¶
-21.5. Request Forgery Attacks¶
-22.1. Registration Policies for QUIC Registries¶
-Any maximum datagram size larger than 1200 bytes can be discovered using Path +
This requirement to support a UDP payload of 1200 bytes limits the space +available for IPv6 extension headers to 32 bytes or IPv4 options to 52 bytes +if the path only supports the IPv6 minimum MTU of 1280 bytes. This affects +Initial packets and path validation.¶
+Any maximum datagram size larger than 1200 bytes can be discovered using Path Maximum Transmission Unit Discovery (PMTUD; see Section 14.2.1) or Datagram -Packetization Layer PMTU Discovery (DPLPMTUD; see Section 14.3).¶
-Enforcement of the max_udp_payload_size transport parameter +Packetization Layer PMTU Discovery (DPLPMTUD; see Section 14.3).¶
+Enforcement of the max_udp_payload_size transport parameter (Section 18.2) might act as an additional limit on the maximum datagram size. A sender can avoid exceeding this limit, once the value is known. However, prior to learning the value of the transport parameter, endpoints risk datagrams being lost if they send datagrams larger than the -smallest allowed maximum datagram size of 1200 bytes.¶
-UDP datagrams MUST NOT be fragmented at the IP layer. In IPv4 +smallest allowed maximum datagram size of 1200 bytes.¶
+UDP datagrams MUST NOT be fragmented at the IP layer. In IPv4 ([IPv4]), the DF bit MUST be set if possible, to prevent -fragmentation on the path.¶
-QUIC sometimes requires datagrams to be no smaller than a certain size; see +fragmentation on the path.¶
+QUIC sometimes requires datagrams to be no smaller than a certain size; see Section 8.1 as an example. However, the size of a datagram is not authenticated. That is, if an endpoint receives a datagram of a certain size, it cannot know that the sender sent the datagram at the same size. Therefore, an endpoint MUST NOT close a connection when it receives a datagram that does not -meet size constraints; the endpoint MAY however discard such datagrams.¶
+meet size constraints; the endpoint MAY however discard such datagrams.¶If a QUIC endpoint determines that the PMTU between any pair of local and remote -IP addresses has fallen below the smallest allowed maximum datagram size of 1200 -bytes, it MUST immediately cease sending QUIC packets, except for those in PMTU -probes or those containing CONNECTION_CLOSE frames, on the affected path. An -endpoint MAY terminate the connection if an alternative path cannot be found.¶
+If a QUIC endpoint determines that the PMTU between any pair of local and +remote IP addresses cannot support the smallest allowed maximum datagram size +of 1200 bytes, it MUST immediately cease sending QUIC packets, except for those +in PMTU probes or those containing CONNECTION_CLOSE frames, on the affected +path. An endpoint MAY terminate the connection if an alternative path cannot be +found.¶
Each pair of local and remote addresses could have a different PMTU. QUIC implementations that implement any kind of PMTU discovery therefore SHOULD maintain a maximum datagram size for each combination of local and remote IP diff --git a/draft-ietf-quic-transport.txt b/draft-ietf-quic-transport.txt index f9a22b1fca..b8aed61306 100644 --- a/draft-ietf-quic-transport.txt +++ b/draft-ietf-quic-transport.txt @@ -4651,6 +4651,11 @@ Table of Contents and 1252 bytes for IPv4. Thus, modern IPv4 and all IPv6 network paths are expected to be able to support QUIC. + Note: This requirement to support a UDP payload of 1200 bytes limits + the space available for IPv6 extension headers to 32 bytes or IPv4 + options to 52 bytes if the path only supports the IPv6 minimum MTU + of 1280 bytes. This affects Initial packets and path validation. + Any maximum datagram size larger than 1200 bytes can be discovered using Path Maximum Transmission Unit Discovery (PMTUD; see Section 14.2.1) or Datagram Packetization Layer PMTU Discovery @@ -4727,7 +4732,7 @@ Table of Contents fragmented or dropped ([RFC8085]). If a QUIC endpoint determines that the PMTU between any pair of local - and remote IP addresses has fallen below the smallest allowed maximum + and remote IP addresses cannot support the smallest allowed maximum datagram size of 1200 bytes, it MUST immediately cease sending QUIC packets, except for those in PMTU probes or those containing CONNECTION_CLOSE frames, on the affected path. An endpoint MAY diff --git a/index.html b/index.html index b852873793..a4fea94a8b 100644 --- a/index.html +++ b/index.html @@ -29,10 +29,10 @@