draft-ietf-quic-manageability-09.txt   draft-ietf-quic-manageability-10.txt 
Network Working Group M. Kuehlewind Network Working Group M. Kuehlewind
Internet-Draft Ericsson Internet-Draft Ericsson
Intended status: Informational B. Trammell Intended status: Informational B. Trammell
Expires: 26 July 2021 Google Expires: 26 August 2021 Google
22 January 2021 22 February 2021
Manageability of the QUIC Transport Protocol Manageability of the QUIC Transport Protocol
draft-ietf-quic-manageability-09 draft-ietf-quic-manageability-10
Abstract Abstract
This document discusses manageability of the QUIC transport protocol, This document discusses manageability of the QUIC transport protocol,
focusing on caveats impacting network operations involving QUIC focusing on caveats impacting network operations involving QUIC
traffic. Its intended audience is network operators, as well as traffic. Its intended audience is network operators, as well as
content providers that rely on the use of QUIC-aware middleboxes, content providers that rely on the use of QUIC-aware middleboxes,
e.g. for load balancing. e.g. for load balancing.
Status of This Memo Status of This Memo
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on 26 July 2021. This Internet-Draft will expire on 26 August 2021.
Copyright Notice Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the Copyright (c) 2021 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/ Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document. license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights Please review these documents carefully, as they describe your rights
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1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Features of the QUIC Wire Image . . . . . . . . . . . . . . . 4 2. Features of the QUIC Wire Image . . . . . . . . . . . . . . . 4
2.1. QUIC Packet Header Structure . . . . . . . . . . . . . . 4 2.1. QUIC Packet Header Structure . . . . . . . . . . . . . . 4
2.2. Coalesced Packets . . . . . . . . . . . . . . . . . . . . 6 2.2. Coalesced Packets . . . . . . . . . . . . . . . . . . . . 6
2.3. Use of Port Numbers . . . . . . . . . . . . . . . . . . . 6 2.3. Use of Port Numbers . . . . . . . . . . . . . . . . . . . 6
2.4. The QUIC Handshake . . . . . . . . . . . . . . . . . . . 7 2.4. The QUIC Handshake . . . . . . . . . . . . . . . . . . . 7
2.5. Integrity Protection of the Wire Image . . . . . . . . . 11 2.5. Integrity Protection of the Wire Image . . . . . . . . . 11
2.6. Connection ID and Rebinding . . . . . . . . . . . . . . . 11 2.6. Connection ID and Rebinding . . . . . . . . . . . . . . . 11
2.7. Packet Numbers . . . . . . . . . . . . . . . . . . . . . 12 2.7. Packet Numbers . . . . . . . . . . . . . . . . . . . . . 12
2.8. Version Negotiation and Greasing . . . . . . . . . . . . 12 2.8. Version Negotiation and Greasing . . . . . . . . . . . . 12
3. Network-visible Information about QUIC Flows . . . . . . . . 12 3. Network-visible Information about QUIC Flows . . . . . . . . 13
3.1. Identifying QUIC Traffic . . . . . . . . . . . . . . . . 13 3.1. Identifying QUIC Traffic . . . . . . . . . . . . . . . . 13
3.1.1. Identifying Negotiated Version . . . . . . . . . . . 13 3.1.1. Identifying Negotiated Version . . . . . . . . . . . 13
3.1.2. Rejection of Garbage Traffic . . . . . . . . . . . . 14 3.1.2. Rejection of Garbage Traffic . . . . . . . . . . . . 14
3.2. Connection Confirmation . . . . . . . . . . . . . . . . . 14 3.2. Connection Confirmation . . . . . . . . . . . . . . . . . 14
3.3. Application Identification . . . . . . . . . . . . . . . 14 3.3. Distinguishing Acknowledgment traffic . . . . . . . . . . 15
3.3.1. Extracting Server Name Indication (SNI) 3.4. Application Identification . . . . . . . . . . . . . . . 15
3.4.1. Extracting Server Name Indication (SNI)
Information . . . . . . . . . . . . . . . . . . . . . 15 Information . . . . . . . . . . . . . . . . . . . . . 15
3.4. Flow Association . . . . . . . . . . . . . . . . . . . . 16 3.5. Flow Association . . . . . . . . . . . . . . . . . . . . 17
3.5. Flow teardown . . . . . . . . . . . . . . . . . . . . . . 16 3.6. Flow teardown . . . . . . . . . . . . . . . . . . . . . . 17
3.6. Flow Symmetry Measurement . . . . . . . . . . . . . . . . 16 3.7. Flow Symmetry Measurement . . . . . . . . . . . . . . . . 17
3.7. Round-Trip Time (RTT) Measurement . . . . . . . . . . . . 17 3.8. Round-Trip Time (RTT) Measurement . . . . . . . . . . . . 17
3.7.1. Measuring Initial RTT . . . . . . . . . . . . . . . . 17 3.8.1. Measuring Initial RTT . . . . . . . . . . . . . . . . 18
3.7.2. Using the Spin Bit for Passive RTT Measurement . . . 17 3.8.2. Using the Spin Bit for Passive RTT Measurement . . . 18
4. Specific Network Management Tasks . . . . . . . . . . . . . . 19 4. Specific Network Management Tasks . . . . . . . . . . . . . . 20
4.1. Stateful Treatment of QUIC Traffic . . . . . . . . . . . 19 4.1. Stateful Treatment of QUIC Traffic . . . . . . . . . . . 20
4.2. Passive Network Performance Measurement and 4.2. Passive Network Performance Measurement and
Troubleshooting . . . . . . . . . . . . . . . . . . . . . 19 Troubleshooting . . . . . . . . . . . . . . . . . . . . . 21
4.3. Server Cooperation with Load Balancers . . . . . . . . . 20 4.3. Server Cooperation with Load Balancers . . . . . . . . . 21
4.4. DDoS Detection and Mitigation . . . . . . . . . . . . . . 20 4.4. DDoS Detection and Mitigation . . . . . . . . . . . . . . 21
4.5. UDP Policing . . . . . . . . . . . . . . . . . . . . . . 21 4.5. UDP Policing . . . . . . . . . . . . . . . . . . . . . . 22
4.6. Distinguishing Acknowledgment traffic . . . . . . . . . . 21 4.6. Handling ICMP Messages . . . . . . . . . . . . . . . . . 22
4.7. Quality of Service handling and ECMP . . . . . . . . . . 22 4.7. Quality of Service handling and ECMP . . . . . . . . . . 23
4.8. QUIC and Network Address Translation (NAT) . . . . . . . 22 4.8. QUIC and Network Address Translation (NAT) . . . . . . . 23
4.8.1. Resource Conservation . . . . . . . . . . . . . . . . 23 4.8.1. Resource Conservation . . . . . . . . . . . . . . . . 24
4.8.2. "Helping" with routing infrastructure issues . . . . 23 4.8.2. "Helping" with routing infrastructure issues . . . . 25
4.9. Filtering behavior . . . . . . . . . . . . . . . . . . . 24 4.9. Filtering behavior . . . . . . . . . . . . . . . . . . . 26
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 25 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 26
6. Security Considerations . . . . . . . . . . . . . . . . . . . 25 6. Security Considerations . . . . . . . . . . . . . . . . . . . 26
7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 25 7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 26
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 25 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 27
9. Appendix . . . . . . . . . . . . . . . . . . . . . . . . . . 26 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 27
9.1. Distinguishing IETF QUIC and Google QUIC Versions . . . . 26 9.1. Normative References . . . . . . . . . . . . . . . . . . 27
9.2. Extracting the CRYPTO frame . . . . . . . . . . . . . . . 27 9.2. Informative References . . . . . . . . . . . . . . . . . 27
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 28 Appendix A. Appendix . . . . . . . . . . . . . . . . . . . . . . 30
10.1. Normative References . . . . . . . . . . . . . . . . . . 28 A.1. Distinguishing IETF QUIC and Google QUIC Versions . . . . 30
10.2. Informative References . . . . . . . . . . . . . . . . . 28 A.2. Extracting the CRYPTO frame . . . . . . . . . . . . . . . 31
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 31 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 32
1. Introduction 1. Introduction
QUIC [QUIC-TRANSPORT] is a new transport protocol encapsulated in UDP QUIC [QUIC-TRANSPORT] is a new transport protocol that is
and encrypted by default. QUIC integrates TLS [QUIC-TLS] to encrypt encapsulated in UDP. QUIC integrates TLS [QUIC-TLS] to encrypt all
all payload data and most control information. The design focused on payload data and most control information. QUIC version 1 was
support of semantics for HTTP, which required changes to HTTP known designed primarily as a transport for HTTP, with the resulting
as HTTP/3 [QUIC-HTTP]. protocol being known as HTTP/3 [QUIC-HTTP].
Given that QUIC is an end-to-end transport protocol, all information Given that QUIC is an end-to-end transport protocol, all information
in the protocol header, even that which can be inspected, is not in the protocol header, even that which can be inspected, is not
meant to be mutable by the network, and is therefore integrity- meant to be mutable by the network, and is therefore integrity-
protected. While less information is visible to the network than for protected. While less information is visible to the network than for
TCP, integrity protection can also simplify troubleshooting, because TCP, integrity protection can also simplify troubleshooting, because
none of the nodes on the network path can modify the transport layer none of the nodes on the network path can modify the transport layer
information. information.
This document provides guidance for network operations that manage This document provides guidance for network operations that manage
QUIC traffic. This includes guidance on how to interpret and utilize QUIC traffic. This includes guidance on how to interpret and utilize
information that is exposed by QUIC to the network, requirements and information that is exposed by QUIC to the network, requirements and
assumptions that the QUIC design with respect to network treatment, assumptions that the QUIC design with respect to network treatment,
and a description of how common network management practices will be and a description of how common network management practices will be
impacted by QUIC. impacted by QUIC.
Since QUIC's wire image [WIRE-IMAGE] is integrity protected and not Since QUIC's wire image [WIRE-IMAGE] is integrity-protected, in-
modifiable on path, in-network operations are not possible without network operations that depend on modification of data are not
terminating the QUIC connection, for instance using a back-to-back possible without the cooperation of an endpoint. Network operation
proxy. Proxy operations are not in scope for this document. A proxy practices that alter data are only possible if performed as a QUIC
can either explicit identify itself as providing a proxy service, or endpoint; this might be possible with the introduction of a proxy
may share the TLS credentials to authenticate as the server and (in which authenticates as an endpoint. Proxy operations are not in
some cases) client acting as a front-facing instance for the endpoint scope for this document.
itself.
Network management is not a one-size-fits-all endeavour: practices Network management is not a one-size-fits-all endeavour: practices
considered necessary or even mandatory within enterprise networks considered necessary or even mandatory within enterprise networks
with certain compliance requirements, for example, would be with certain compliance requirements, for example, would be
impermissible on other networks without those requirements. This impermissible on other networks without those requirements. This
document therefore does not make any specific recommendations as to document therefore does not make any specific recommendations as to
which practices should or should not be applied; for each practice, which practices should or should not be applied; for each practice,
it describes what is and is not possible with the QUIC transport it describes what is and is not possible with the QUIC transport
protocol as defined. protocol as defined.
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Negotiation Packet, are both inspectable and invariant Negotiation Packet, are both inspectable and invariant
[QUIC-INVARIANTS]. [QUIC-INVARIANTS].
This document describes version 1 of the QUIC protocol, whose wire This document describes version 1 of the QUIC protocol, whose wire
image is fully defined in [QUIC-TRANSPORT] and [QUIC-TLS]. Features image is fully defined in [QUIC-TRANSPORT] and [QUIC-TLS]. Features
of the wire image described herein may change in future versions of of the wire image described herein may change in future versions of
the protocol, except when specified as an invariant the protocol, except when specified as an invariant
[QUIC-INVARIANTS], and cannot be used to identify QUIC as a protocol [QUIC-INVARIANTS], and cannot be used to identify QUIC as a protocol
or to infer the behavior of future versions of QUIC. or to infer the behavior of future versions of QUIC.
Section 9.1 provides non-normative guidance on the identification of Appendix A.1 provides non-normative guidance on the identification of
QUIC version 1 packets compared to some pre-standard versions. QUIC version 1 packets compared to some pre-standard versions.
2.1. QUIC Packet Header Structure 2.1. QUIC Packet Header Structure
QUIC packets may have either a long header, or a short header. The QUIC packets may have either a long header, or a short header. The
first bit of the QUIC header is the Header Form bit, and indicates first bit of the QUIC header is the Header Form bit, and indicates
which type of header is present. The purpose of this bit is which type of header is present. The purpose of this bit is
invariant across QUIC versions. invariant across QUIC versions.
The long header exposes more information. It is used during The long header exposes more information. It is used during
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only an optional destination connection ID and the spin bit for RTT only an optional destination connection ID and the spin bit for RTT
measurement. measurement.
The following information is exposed in QUIC packet headers: The following information is exposed in QUIC packet headers:
* "fixed bit": the second most significant bit of the first octet * "fixed bit": the second most significant bit of the first octet
most QUIC packets of the current version is currently set to 1, most QUIC packets of the current version is currently set to 1,
for endpoints to demultiplex with other UDP-encapsulated for endpoints to demultiplex with other UDP-encapsulated
protocols. Even thought this bit is fixed in the QUICv1 protocols. Even thought this bit is fixed in the QUICv1
specification, endpoints may use a version or extension that specification, endpoints may use a version or extension that
varies the bit. Therefore, observers cannot reliably use it as an varies the bit. Therefore, observers cannot depend on it as an
identifier for QUIC. identifier for QUIC.
* latency spin bit: the third most significant bit of first octet in * latency spin bit: the third most significant bit of first octet in
the short packet header. The spin bit is set by endpoints such the short packet header. The spin bit is set by endpoints such
that tracking edge transitions can be used to passively observe that tracking edge transitions can be used to passively observe
end-to-end RTT. See Section 3.7.2 for further details. end-to-end RTT. See Section 3.8.2 for further details.
* header type: the long header has a 2 bit packet type field * header type: the long header has a 2 bit packet type field
following the Header Form and fixed bits. Header types correspond following the Header Form and fixed bits. Header types correspond
to stages of the handshake; see Section 17.2 of [QUIC-TRANSPORT] to stages of the handshake; see Section 17.2 of [QUIC-TRANSPORT]
for details. for details.
* version number: the version number is present in the long header, * version number: the version number is present in the long header,
and identifies the version used for that packet. During Version and identifies the version used for that packet. During Version
Negotiation (see Section 2.8 and Section 17.2.1 of Negotiation (see Section 2.8 and Section 17.2.1 of
[QUIC-TRANSPORT]), the version number field has a special value [QUIC-TRANSPORT]), the version number field has a special value
(0x00000000) that identifies the packet as a Version Negotiation (0x00000000) that identifies the packet as a Version Negotiation
packet. Many QUIC versions that start with 0xff implement IETF packet. Upon time of publishing of this document, QUIC versions
drafts. QUIC versions that start with 0x0000 are reserved for that start with 0xff implement IETF drafts. QUIC version 1 uses
IETF consensus documents. For example, QUIC version 1 uses
version 0x00000001. Operators should expect to observe packets version 0x00000001. Operators should expect to observe packets
with other version numbers as a result of various internet with other version numbers as a result of various Internet
experiments and future standards. experiments and future standards.
* source and destination connection ID: short and long packet * source and destination connection ID: short and long packet
headers carry a destination connection ID, a variable-length field headers carry a destination connection ID, a variable-length field
that can be used to identify the connection associated with a QUIC that can be used to identify the connection associated with a QUIC
packet, for load-balancing and NAT rebinding purposes; see packet, for load-balancing and NAT rebinding purposes; see
Section 4.3 and Section 2.6. Long packet headers additionally Section 4.3 and Section 2.6. Long packet headers additionally
carry a source connection ID. The source connection ID carry a source connection ID. The source connection ID
corresponds to the destination connection ID the source would like corresponds to the destination connection ID the source would like
to have on packets sent to it, and is only present on long packet to have on packets sent to it, and is only present on long packet
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one short header packets. When packets are coalesced, the Length one short header packets. When packets are coalesced, the Length
fields in the long headers are used to separate QUIC packets; see fields in the long headers are used to separate QUIC packets; see
Section 12.2 of [QUIC-TRANSPORT]. The length header field is Section 12.2 of [QUIC-TRANSPORT]. The length header field is
variable length, and its position in the header is also variable variable length, and its position in the header is also variable
depending on the length of the source and destination connection ID; depending on the length of the source and destination connection ID;
see Section 17.2 of [QUIC-TRANSPORT]. see Section 17.2 of [QUIC-TRANSPORT].
2.3. Use of Port Numbers 2.3. Use of Port Numbers
Applications that have a mapping for TCP as well as QUIC are expected Applications that have a mapping for TCP as well as QUIC are expected
to use the same port number for both services. However, as with TCP- to use the same port number for both services. However, as for all
based services, especially when application layer information is other IETF transports [RFC7605], there is no guarantee that a
encrypted, there is no guarantee that a specific application will use specific application will use a given registered port, or that a
the registered port, or the used port is carrying traffic belonging given port carries traffic belonging to the respective registered
to the respective registered service. For example, [QUIC-HTTP] service, especially when application layer information is encrypted.
specifies the use of Alt-Svc for discovery of HTTP/3 services on For example, [QUIC-HTTP] specifies the use of Alt-Svc for discovery
other ports. of HTTP/3 services on other ports.
Further, as QUIC has a connection ID, it is also possible to maintain Further, as QUIC has a connection ID, it is also possible to maintain
multiple QUIC connections over one 5-tuple. However, if the multiple QUIC connections over one 5-tuple. However, if the
connection ID is not present in the packet header, all packets of the connection ID is not present in the packet header, all packets of the
5-tuple belong to the same QUIC connection. 5-tuple belong to the same QUIC connection.
2.4. The QUIC Handshake 2.4. The QUIC Handshake
New QUIC connections are established using a handshake, which is New QUIC connections are established using a handshake, which is
distinguishable on the wire and contains some information that can be distinguishable on the wire and contains some information that can be
passively observed. passively observed.
To illustrate the information visible in the QUIC wire image during To illustrate the information visible in the QUIC wire image during
the handshake, we first show the general communication pattern the handshake, we first show the general communication pattern
visible in the UDP datagrams containing the QUIC handshake, then visible in the UDP datagrams containing the QUIC handshake, then
examine each of the datagrams in detail. examine each of the datagrams in detail.
In the nominal case, the QUIC handshake can be recognized on the wire The QUIC handshake can normally be recognized on the wire through at
through at least four datagrams we'll call "QUIC Client Hello", "QUIC least four datagrams we'll call "QUIC Client Hello", "QUIC Server
Server Hello", and "Initial Completion", and "Handshake Completion", Hello", and "Initial Completion", and "Handshake Completion", for
for purposes of this illustration, as shown in Figure 1. purposes of this illustration, as shown in Figure 1.
Packets in the handshake belong to three separate cryptographic and Packets in the handshake belong to three separate cryptographic and
transport contexts ("Initial", which contains observable payload, and transport contexts ("Initial", which contains observable payload, and
"Handshake" and "1-RTT", which do not). QUIC packets in separate "Handshake" and "1-RTT", which do not). QUIC packets in separate
contexts during the handshake are generally coalesced (see contexts during the handshake are generally coalesced (see
Section 2.2) in order to reduce the number of UDP datagrams sent Section 2.2) in order to reduce the number of UDP datagrams sent
during the handshake. during the handshake.
As shown here, the client can send 0-RTT data as soon as it has sent As shown here, the client can send 0-RTT data as soon as it has sent
its Client Hello, and the server can send 1-RTT data as soon as it its Client Hello, and the server can send 1-RTT data as soon as it
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Hello datagram as shown in Figure 2, which elicits a QUIC Server Hello datagram as shown in Figure 2, which elicits a QUIC Server
Hello datagram as shown in Figure 3 typically containing three Hello datagram as shown in Figure 3 typically containing three
packets: an Initial packet with the Server Hello, a Handshake packet packets: an Initial packet with the Server Hello, a Handshake packet
with the rest of the server's side of the TLS handshake, and initial with the rest of the server's side of the TLS handshake, and initial
1-RTT data, if present. 1-RTT data, if present.
The Initial Completion datagram contains at least one Handshake The Initial Completion datagram contains at least one Handshake
packet and some also include an Initial packet. packet and some also include an Initial packet.
Datagrams that contain a QUIC Initial Packet (Client Hello, Server Datagrams that contain a QUIC Initial Packet (Client Hello, Server
Hello, and some Initial Completion) must be at least 1200 octets Hello, and some Initial Completion) contain at least 1200 octets of
long. This protects against amplification attacks and verifies that UDP payload. This protects against amplification attacks and
the network path meets minimum Maximum Transmission Unit (MTU) verifies that the network path meets the requirements for the minimum
requirements. This is usually accomplished with either the addition QUIC IP packet size, see Section 14 of [QUIC-TRANSPORT]. This is
of PADDING frames to the Initial packet, or coalescing of the Initial accomplished by either adding PADDING frames within the Initial
Packet with packets from other encryption contexts. packet, coalescing other packets with the Initial packet, or leaving
unused payload in the UDP packet after the Initial packet. A network
path needs to be able to forward at least this size of packet for
QUIC to be used.
The content of QUIC Initial packets are encrypted using Initial The content of QUIC Initial packets are encrypted using Initial
Secrets, which are derived from a per-version constant and the Secrets, which are derived from a per-version constant and the
client's destination connection ID; they are therefore observable by client's destination connection ID; they are therefore observable by
any on-path device that knows the per-version constant. We therefore any on-path device that knows the per-version constant. They are
consider these as visible in our illustration. The content of QUIC therefore considered visible in this illustration. The content of
Handshake packets are encrypted using keys established during the QUIC Handshake packets are encrypted using keys established during
initial handshake exchange, and are therefore not visible. the initial handshake exchange, and are therefore not visible.
Initial, Handshake, and the Short Header packets transmitted after Initial, Handshake, and the Short Header packets transmitted after
the handshake belong to cryptographic and transport contexts. The the handshake belong to cryptographic and transport contexts. The
Initial Completion Figure 4 and the Handshake Completion Figure 5 Initial Completion Figure 4 and the Handshake Completion Figure 5
datagrams finish these first two contexts, by sending the final datagrams finish these first two contexts, by sending the final
acknowledgment and finishing the transmission of CRYPTO frames. acknowledgment and finishing the transmission of CRYPTO frames.
+----------------------------------------------------------+ +----------------------------------------------------------+
| UDP header (source and destination UDP ports) | | UDP header (source and destination UDP ports) |
+----------------------------------------------------------+ +----------------------------------------------------------+
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| QUIC CRYPTO frame header | | | QUIC CRYPTO frame header | |
+----------------------------------------------------------+ | +----------------------------------------------------------+ |
| TLS Client Hello (incl. TLS SNI) | | | TLS Client Hello (incl. TLS SNI) | |
+----------------------------------------------------------+ | +----------------------------------------------------------+ |
| QUIC PADDING frames | | | QUIC PADDING frames | |
+----------------------------------------------------------+<-+ +----------------------------------------------------------+<-+
Figure 2: Typical QUIC Client Hello datagram pattern with no 0-RTT Figure 2: Typical QUIC Client Hello datagram pattern with no 0-RTT
The Client Hello datagram exposes version number, source and The Client Hello datagram exposes version number, source and
destination connection IDs in the clear. Information in the TLS destination connection IDs without encryption. Information in the
Client Hello frame, including any TLS Server Name Indication (SNI) TLS Client Hello frame, including any TLS Server Name Indication
present, is obfuscated using the Initial secret. Note that the (SNI) present, is obfuscated using the Initial secret. Note that the
location of PADDING is implementation-dependent, and PADDING frames location of PADDING is implementation-dependent, and PADDING frames
may not appear in a coalesced Initial packet. may not appear in a coalesced Initial packet.
+------------------------------------------------------------+ +------------------------------------------------------------+
| UDP header (source and destination UDP ports) | | UDP header (source and destination UDP ports) |
+------------------------------------------------------------+ +------------------------------------------------------------+
| QUIC long header (type = Initial, Version, DCID, SCID) (Length) | QUIC long header (type = Initial, Version, DCID, SCID) (Length)
+------------------------------------------------------------+ | +------------------------------------------------------------+ |
| QUIC CRYPTO frame header | | | QUIC CRYPTO frame header | |
+------------------------------------------------------------+ | +------------------------------------------------------------+ |
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+------------------------------------------------------------+<-+ +------------------------------------------------------------+<-+
| QUIC short header | | QUIC short header |
+------------------------------------------------------------+ +------------------------------------------------------------+
| 1-RTT encrypted payload | | 1-RTT encrypted payload |
+------------------------------------------------------------+ +------------------------------------------------------------+
Figure 4: Typical QUIC Initial Completion datagram pattern Figure 4: Typical QUIC Initial Completion datagram pattern
The Initial Completion datagram does not expose any additional The Initial Completion datagram does not expose any additional
information; however, recognizing it can be used to determine that a information; however, recognizing it can be used to determine that a
handshake has completed (see Section 3.2), and for three-way handshake has completed (see Section 3.2), and for three-way
handshake RTT estimation as in Section 3.7. handshake RTT estimation as in Section 3.8.
+------------------------------------------------------------+ +------------------------------------------------------------+
| UDP header (source and destination UDP ports) | | UDP header (source and destination UDP ports) |
+------------------------------------------------------------+ +------------------------------------------------------------+
| QUIC long header (type = Handshake, Version, DCID, SCID) (Length) | QUIC long header (type = Handshake, Version, DCID, SCID) (Length)
+------------------------------------------------------------+ | +------------------------------------------------------------+ |
| encrypted payload (presumably ACK frame) | | | encrypted payload (presumably ACK frame) | |
+------------------------------------------------------------+<-+ +------------------------------------------------------------+<-+
| QUIC short header | | QUIC short header |
+------------------------------------------------------------+ +------------------------------------------------------------+
skipping to change at page 11, line 5 skipping to change at page 11, line 5
| 0-rtt encrypted payload | | | 0-rtt encrypted payload | |
+----------------------------------------------------------+<-+ +----------------------------------------------------------+<-+
Figure 6: Typical 0-RTT QUIC Client Hello datagram pattern Figure 6: Typical 0-RTT QUIC Client Hello datagram pattern
In a 0-RTT QUIC Client Hello datagram, the PADDING frame is only In a 0-RTT QUIC Client Hello datagram, the PADDING frame is only
present if necessary to increase the size of the datagram with 0RTT present if necessary to increase the size of the datagram with 0RTT
data to at least 1200 bytes. Additional datagrams containing only data to at least 1200 bytes. Additional datagrams containing only
0-RTT protected long header packets may be sent from the client to 0-RTT protected long header packets may be sent from the client to
the server after the Client Hello datagram, containing the rest of the server after the Client Hello datagram, containing the rest of
the 0-RTT data. The amount of 0-RTT protected data is limited by the the 0-RTT data. The amount of 0-RTT protected data that can be sent
initial congestion window, typically around 10 packets [RFC6928]. in the first round is limited by the initial congestion window,
typically around 10 packets (see Section 7.2 of [QUIC-RECOVERY]).
2.5. Integrity Protection of the Wire Image 2.5. Integrity Protection of the Wire Image
As soon as the cryptographic context is established, all information As soon as the cryptographic context is established, all information
in the QUIC header, including exposed information, is integrity in the QUIC header, including exposed information, is integrity
protected. Further, information that was sent and exposed in protected. Further, information that was sent and exposed in
handshake packets sent before the cryptographic context was handshake packets sent before the cryptographic context was
established are validated later during the cryptographic handshake. established are validated later during the cryptographic handshake.
Therefore, devices on path cannot alter any information or bits in Therefore, devices on path cannot alter any information or bits in
QUIC packet headers, except specific parts of Initial packets, since QUIC packets. Such alterations would cause the integrity check to
alteration of header information will lead to a failed integrity fail, which results in the receiver discarding the packet. Some
check at the receiver, and can even lead to connection termination. parts of Initial packets could be altered by removing and re-applying
the authenticated encryption without immediate discard at the
receiver. However, the cryptographic handshake validates most fields
and any modifications in those fields will result in connection
establishment failing later on.
2.6. Connection ID and Rebinding 2.6. Connection ID and Rebinding
The connection ID in the QUIC packet headers allows routing of QUIC The connection ID in the QUIC packet headers allows routing of QUIC
packets at load balancers on other than five-tuple information, packets at load balancers on other than five-tuple information,
ensuring that related flows are appropriately balanced together; and ensuring that related flows are appropriately balanced together; and
to allow rebinding of a connection after one of the endpoint's to allow rebinding of a connection after one of the endpoint's
addresses changes - usually the client's. Client and server addresses changes - usually the client's. Client and server
negotiate connection IDs during the handshake; typically, however, negotiate connection IDs during the handshake; typically, however,
only the server will request a connection ID for the lifetime of the only the server will request a connection ID for the lifetime of the
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The packet number field is always present in the QUIC packet header; The packet number field is always present in the QUIC packet header;
however, it is always encrypted. The encryption key for packet however, it is always encrypted. The encryption key for packet
number protection on handshake packets sent before cryptographic number protection on handshake packets sent before cryptographic
context establishment is specific to the QUIC version, while packet context establishment is specific to the QUIC version, while packet
number protection on subsequent packets uses secrets derived from the number protection on subsequent packets uses secrets derived from the
end-to-end cryptographic context. Packet numbers are therefore not end-to-end cryptographic context. Packet numbers are therefore not
part of the wire image that is visible to on-path observers. part of the wire image that is visible to on-path observers.
2.8. Version Negotiation and Greasing 2.8. Version Negotiation and Greasing
Version Negotiation packets are not intrinsically protected, but QUIC Version Negotiation packets are used by the server to indicate that a
versions can use later encrypted messages to verify that they were requested version from the client is not supported (see section 6 of
authentic. Therefore any manipulation of this list will be detected [QUIC-TRANSPORT]. Version Negotiation packets are not intrinsically
and may cause the endpoints to terminate the connection attempt. protected, but QUIC versions can use later encrypted messages to
verify that they were authentic. Therefore any modification of this
list will be detected and may cause the endpoints to terminate the
connection attempt.
Also note that the list of versions in the Version Negotiation packet Also note that the list of versions in the Version Negotiation packet
may contain reserved versions. This mechanism is used to avoid may contain reserved versions. This mechanism is used to avoid
ossification in the implementation on the selection mechanism. ossification in the implementation on the selection mechanism.
Further, a client may send a Initial Client packet with a reserved Further, a client may send a Initial Client packet with a reserved
version number to trigger version negotiation. In the Version version number to trigger version negotiation. In the Version
Negotiation packet the connection ID and packet number of the Client Negotiation packet the connection ID and packet number of the Client
Initial packet are reflected to provide a proof of return- Initial packet are reflected to provide a proof of return-
routability. Therefore changing this information will also cause the routability. Therefore changing this information will also cause the
connection to fail. connection to fail.
skipping to change at page 13, line 21 skipping to change at page 13, line 29
[QUIC-HTTP] at the time of this writing; however, many other [QUIC-HTTP] at the time of this writing; however, many other
applications are currently being defined and deployed over QUIC, so applications are currently being defined and deployed over QUIC, so
an assumption that all QUIC traffic is HTTP/3 is not valid. HTTP an assumption that all QUIC traffic is HTTP/3 is not valid. HTTP
over QUIC uses UDP port 443 by default, although URLs referring to over QUIC uses UDP port 443 by default, although URLs referring to
resources available over HTTP/3 may specify alternate port numbers. resources available over HTTP/3 may specify alternate port numbers.
Simple assumptions about whether a given flow is using QUIC based Simple assumptions about whether a given flow is using QUIC based
upon a UDP port number may therefore not hold; see also [RFC7605] upon a UDP port number may therefore not hold; see also [RFC7605]
section 5. section 5.
While the second most significant bit (0x40) of the first octet is While the second most significant bit (0x40) of the first octet is
set to 1 in most QUIC packets of the current version (see set to 1 in most QUIC packets of the current version (see Section 2.1
Section 2.1), this method of recognizing QUIC traffic is NOT and section 17 of [QUIC-TRANSPORT]), this method of recognizing QUIC
RECOMMENDED. First, it only provides one bit of information and is traffic is not reliable. First, it only provides one bit of
quite prone to collide with UDP-based protocols other than those that information and is prone to collision with UDP-based protocols other
this static bit is meant to allow multiplexing with. Second, this than those that this static bit is meant to allow multiplexing with.
feature of the wire image is not invariant [QUIC-INVARIANTS] and may Second, this feature of the wire image is not invariant
change in future versions of the protocol, or even be negotiated [QUIC-INVARIANTS] and may change in future versions of the protocol,
during the handshake via the use of transport parameters. or even be negotiated during the handshake via the use of transport
parameters.
Even though transport parameters transmitted in the client initial Even though transport parameters transmitted in the client initial
are obserable by the network, they cannot be modified by the network are obserable by the network, they cannot be modified by the network
without risking connection failure. Further, the negotiated reply without risking connection failure. Further, the negotiated reply
from the server cannot be observed, so observers on the network from the server cannot be observed, so observers on the network
cannot know which parameters are actually in use. cannot know which parameters are actually in use.
3.1.1. Identifying Negotiated Version 3.1.1. Identifying Negotiated Version
An in-network observer assuming that a set of packets belongs to a An in-network observer assuming that a set of packets belongs to a
QUIC flow can infer the version number in use by observing the QUIC flow can infer the version number in use by observing the
handshake: an Initial packet with a given version from a client to handshake: for QUIC version 1 if the version number in the Initial
which a server responds with an Initial packet with the same version packet from a client is the same as the version number in Initial
implies acceptance of that version. packet of the server response, that version has been accepted by both
endpoints to be used for the rest of the connection.
Negotiated version cannot be identified for flows for which a Negotiated version cannot be identified for flows for which a
handshake is not observed, such as in the case of connection handshake is not observed, such as in the case of connection
migration; however, these flows can be associated with flows for migration; however, it might be possible to associate a flow with a
which a version has been identified; see Section 3.4. flow for which a version has been identified; see Section 3.5.
This document focuses on QUIC Version 1, and this section applies This document focuses on QUIC Version 1, and this section applies
only to packets belonging to Version 1 QUIC flows; for purposes of only to packets belonging to Version 1 QUIC flows; for purposes of
on-path observation, it assumes that these packets have been on-path observation, it assumes that these packets have been
identified as such through the observation of a version number identified as such through the observation of a version number
exchange as described above. exchange as described above.
3.1.2. Rejection of Garbage Traffic 3.1.2. Rejection of Garbage Traffic
A related question is whether a first packet of a given flow on a A related question is whether a first packet of a given flow on a
skipping to change at page 14, line 42 skipping to change at page 15, line 5
before the Initial packet. before the Initial packet.
Note that clients send Initial packets before servers do, servers Note that clients send Initial packets before servers do, servers
send Handshake packets before clients do, and only clients send send Handshake packets before clients do, and only clients send
Initial packets with tokens. Therefore, the role as a client or Initial packets with tokens. Therefore, the role as a client or
server can generally be confirmed by an on- path observer. An server can generally be confirmed by an on- path observer. An
attempted connection after Retry can be detected by correlating the attempted connection after Retry can be detected by correlating the
token on the Retry with the token on the subsequent Initial packet token on the Retry with the token on the subsequent Initial packet
and the destination connection ID of the new Initial packet. and the destination connection ID of the new Initial packet.
3.3. Application Identification 3.3. Distinguishing Acknowledgment traffic
Some deployed in-network functions distinguish pure-acknowledgment
(ACK) packets from packets carrying upper-layer data in order to
attempt to enhance performance, for example by queueing ACKs
differently or manipulating ACK signaling. Distinguishing ACK
packets is trivial in TCP, but not supported by QUIC, since
acknowledgment signaling is carried inside QUIC's encrypted payload,
and ACK manipulation is impossible. Specifically, heuristics
attempting to distinguish ACK-only packets from payload-carrying
packets based on packet size are likely to fail, and are not
recommended to use as a way to construe internals of QUIC's operation
as those mechanisms can change, e.g., due to the use of extensions.
3.4. Application Identification
The cleartext TLS handshake may contain Server Name Indication (SNI) The cleartext TLS handshake may contain Server Name Indication (SNI)
[RFC6066], by which the client reveals the name of the server it [RFC6066], by which the client reveals the name of the server it
intends to connect to, in order to allow the server to present a intends to connect to, in order to allow the server to present a
certificate based on that name. It may also contain information from certificate based on that name. It may also contain information from
Application-Layer Protocol Negotiation (ALPN) [RFC7301], by which the Application-Layer Protocol Negotiation (ALPN) [RFC7301], by which the
client exposes the names of application-layer protocols it supports; client exposes the names of application-layer protocols it supports;
an observer can deduce that one of those protocols will be used if an observer can deduce that one of those protocols will be used if
the connection continues. the connection continues.
Work is currently underway in the TLS working group to encrypt the Work is currently underway in the TLS working group to encrypt the
SNI in TLS 1.3 [TLS-ESNI]. This would make SNI-based application SNI in TLS 1.3 [TLS-ESNI]. This would make SNI-based application
identification impossible through passive measurement for QUIC and identification impossible by on-path observation for QUIC and other
other protocols that use TLS. protocols that use TLS.
3.3.1. Extracting Server Name Indication (SNI) Information 3.4.1. Extracting Server Name Indication (SNI) Information
If the SNI is not encrypted it can be derived from the QUIC Initial If the SNI is not encrypted it can be derived from the QUIC Initial
packet by calculating the Initial Secret to decrypt the packet packet by calculating the Initial Secret to decrypt the packet
payload and parse the QUIC CRYPTO Frame containing the TLS payload and parse the QUIC CRYPTO Frame containing the TLS
ClientHello. ClientHello.
As both the initial salt for the Initial Secret as well as CRYPTO As both the initial salt for the Initial Secret as well as CRYPTO
frame itself are version-specific, the first step is always to parse frame itself are version-specific, the first step is always to parse
the version number (second to sixth byte of the long header). Note the version number (second to sixth byte of the long header). Note
that only long header packets carry the version number, so it is that only long header packets carry the version number, so it is
necessary to also check the if first bit of the QUIC packet is set to necessary to also check the if first bit of the QUIC packet is set to
1, indicating a long header. 1, indicating a long header.
Note that proprietary QUIC versions, that have been deployed before Note that proprietary QUIC versions, that have been deployed before
standardization, might not set the first bit in a QUIC long header standardization, might not set the first bit in a QUIC long header
packets to 1. To parse these versions, example code is provided in packets to 1. To parse these versions, example code is provided in
the appendix (see Section 9.1), however, it is expected that these the appendix (see Appendix A.1), however, it is expected that these
versions will gradually disappear over time. versions will gradually disappear over time.
When the version has been identified as QUIC version 1, the packet When the version has been identified as QUIC version 1, the packet
type needs to be verified as an Initial packet by checking that the type needs to be verified as an Initial packet by checking that the
third and fourth bit of the header are both set to 0. Then the third and fourth bit of the header are both set to 0. Then the
client destination connection ID needs to be extracted to calculate client destination connection ID needs to be extracted to calculate
the Initial Secret together with the version specific initial salt, the Initial Secret together with the version specific initial salt,
as described in [QUIC-TLS]. The length of the connection ID is as described in [QUIC-TLS]. The length of the connection ID is
indicated in the 6th byte of the header followed by the connection ID indicated in the 6th byte of the header followed by the connection ID
itself. itself.
skipping to change at page 16, line 8 skipping to change at page 16, line 38
specified in Section 16 of [QUIC-TRANSPORT]. specified in Section 16 of [QUIC-TRANSPORT].
After decryption, the Initial Client packet can be parsed to detect After decryption, the Initial Client packet can be parsed to detect
the CRYPTO frame that contains the TLS Client Hello, which then can the CRYPTO frame that contains the TLS Client Hello, which then can
be parsed similarly to TLS over TCP connections. The Initial client be parsed similarly to TLS over TCP connections. The Initial client
packet may contain other frames, so the first bytes of each frame packet may contain other frames, so the first bytes of each frame
need to be checked to identify the frame type, and if needed skip need to be checked to identify the frame type, and if needed skip
over it. Note that the length of the frames is dependent on the over it. Note that the length of the frames is dependent on the
frame type. In QUIC version 1, the packet is expected to only carry frame type. In QUIC version 1, the packet is expected to only carry
the CRYPTO frame and optionally padding frames. However, PADDING the CRYPTO frame and optionally padding frames. However, PADDING
frames, which are each one byte of zeros, may also occur before or frames, each consisting of a single zero byte, may also occur before
after the CRYPTO frame. or after the CRYPTO frame.
Note that client Initial packets after the first do not always use Note that client Initial packets after the first do not always use
the destination connection ID that was used to generate the Initial the destination connection ID that was used to generate the Initial
keys. Therefore, attempts to decrypt these packets using the keys. Therefore, attempts to decrypt these packets using the
procedure above might fail. procedure above might fail.
3.4. Flow Association 3.5. Flow Association
The QUIC connection ID (see Section 2.6) is designed to allow an on- The QUIC connection ID (see Section 2.6) is designed to allow an on-
path device such as a load-balancer to associate two flows as path device such as a load-balancer to associate two flows as
identified by five-tuple when the address and port of one of the identified by five-tuple when the address and port of one of the
endpoints changes; e.g. due to NAT rebinding or server IP address endpoints changes; e.g. due to NAT rebinding or server IP address
migration. An observer keeping flow state can associate a connection migration. An observer keeping flow state can associate a connection
ID with a given flow, and can associate a known flow with a new flow ID with a given flow, and can associate a known flow with a new flow
when when observing a packet sharing a connection ID and one endpoint when when observing a packet sharing a connection ID and one endpoint
address (IP address and port) with the known flow. address (IP address and port) with the known flow.
However, since the connection ID may change multiple times during the However, since the connection ID may change multiple times during the
lifetime of a flow, and the negotiation of connection ID changes is lifetime of a flow, and the negotiation of connection ID changes is
encrypted, packets with the same 5-tuple but different connection IDs encrypted, packets with the same 5-tuple but different connection IDs
may or may not belong to the same connection. may or may not belong to the same connection.
The connection ID value should be treated as opaque; see Section 4.3 The connection ID value should be treated as opaque; see Section 4.3
for caveats regarding connection ID selection at servers. for caveats regarding connection ID selection at servers.
3.5. Flow teardown 3.6. Flow teardown
QUIC does not expose the end of a connection; the only indication to QUIC does not expose the end of a connection; the only indication to
on-path devices that a flow has ended is that packets are no longer on-path devices that a flow has ended is that packets are no longer
observed. Stateful devices on path such as NATs and firewalls must observed. Stateful devices on path such as NATs and firewalls must
therefore use idle timeouts to determine when to drop state for QUIC therefore use idle timeouts to determine when to drop state for QUIC
flows, see further section Section 4.1. flows, see further section Section 4.1.
3.6. Flow Symmetry Measurement 3.7. Flow Symmetry Measurement
QUIC explicitly exposes which side of a connection is a client and QUIC explicitly exposes which side of a connection is a client and
which side is a server during the handshake. In addition, the which side is a server during the handshake. In addition, the
symmetry of a flow (whether primarily client-to-server, primarily symmetry of a flow (whether primarily client-to-server, primarily
server-to-client, or roughly bidirectional, as input to basic traffic server-to-client, or roughly bidirectional, as input to basic traffic
classification techniques) can be inferred through the measurement of classification techniques) can be inferred through the measurement of
data rate in each direction. While QUIC traffic is protected and data rate in each direction. While QUIC traffic is protected and
ACKs may be padded, padding is not required. ACKs may be padded, padding is not required.
3.7. Round-Trip Time (RTT) Measurement 3.8. Round-Trip Time (RTT) Measurement
Round-trip time of QUIC flows can be inferred by observation once per Round-trip time of QUIC flows can be inferred by observation once per
flow, during the handshake, as in passive TCP measurement; this flow, during the handshake, as in passive TCP measurement; this
requires parsing of the QUIC packet header and recognition of the requires parsing of the QUIC packet header and recognition of the
handshake, as illustrated in Section 2.4. It can also be inferred handshake, as illustrated in Section 2.4. It can also be inferred
during the flow's lifetime, if the endpoints use the spin bit during the flow's lifetime, if the endpoints use the spin bit
facility described below and in [QUIC-TRANSPORT], section 17.3.1. facility described below and in [QUIC-TRANSPORT], section 17.3.1.
3.7.1. Measuring Initial RTT 3.8.1. Measuring Initial RTT
In the common case, the delay between the Initial packet containing In the common case, the delay between the Initial packet containing
the TLS Client Hello and the Handshake packet containing the TLS the TLS Client Hello and the Handshake packet containing the TLS
Server Hello represents the RTT component on the path between the Server Hello represents the RTT component on the path between the
observer and the server. The delay between the TLS Server Hello and observer and the server. The delay between the TLS Server Hello and
the Handshake packet containing the TLS Finished message sent by the the Handshake packet containing the TLS Finished message sent by the
client represents the RTT component on the path between the observer client represents the RTT component on the path between the observer
and the client. While the client may send 0-RTT Protected packets and the client. While the client may send 0-RTT Protected packets
after the Initial packet during 0-RTT connection re-establishment, after the Initial packet during 0-RTT connection re-establishment,
these can be ignored for RTT measurement purposes. these can be ignored for RTT measurement purposes.
Handshake RTT can be measured by adding the client-to-observer and Handshake RTT can be measured by adding the client-to-observer and
observer-to-server RTT components together. This measurement observer-to-server RTT components together. This measurement
necessarily includes any transport and application layer delay (the necessarily includes any transport and application layer delay (the
latter mainly caused by the asymmetric crypto operations associated latter mainly caused by the asymmetric crypto operations associated
with the TLS handshake) at both sides. with the TLS handshake) at both sides.
3.7.2. Using the Spin Bit for Passive RTT Measurement 3.8.2. Using the Spin Bit for Passive RTT Measurement
The spin bit provides an additional method to measure per-flow RTT The spin bit provides a version-specific method to measure per-flow
from observation points on the network path throughout the duration RTT from observation points on the network path throughout the
of a connection. Endpoint participation in spin bit signaling is duration of a connection. See section 17.4 of [QUIC-TRANSPORT] for
optional in QUIC. That is, while its location is fixed in this the definition of the spin bit in Version 1 of QUIC. Endpoint
version of QUIC, an endpoint can unilaterally choose to not support participation in spin bit signaling is optional. That is, while its
"spinning" the bit. Use of the spin bit for RTT measurement by location is fixed in this version of QUIC, an endpoint can
devices on path is only possible when both endpoints enable it. Some unilaterally choose to not support "spinning" the bit.
endpoints may disable use of the spin bit by default, others only in
specific deployment scenarios, e.g. for servers and clients where the Use of the spin bit for RTT measurement by devices on path is only
RTT would reveal the presence of a VPN or proxy. To avoid making possible when both endpoints enable it. Some endpoints may disable
these connections identifiable based on the usage of the spin bit, use of the spin bit by default, others only in specific deployment
all endpoints randomly disable "spinning" for at least one eighth of scenarios, e.g. for servers and clients where the RTT would reveal
connections, even if otherwise enabled by default. An endpoint not the presence of a VPN or proxy. To avoid making these connections
participating in spin bit signaling for a given connection can use a identifiable based on the usage of the spin bit, all endpoints
fixed spin value for the duration of the connection, or can set the randomly disable "spinning" for at least one eighth of connections,
bit randomly on each packet sent. even if otherwise enabled by default. An endpoint not participating
in spin bit signaling for a given connection can use a fixed spin
value for the duration of the connection, or can set the bit randomly
on each packet sent.
When in use and a QUIC flow sends data continuously, the latency spin When in use and a QUIC flow sends data continuously, the latency spin
bit in each direction changes value once per round-trip time (RTT). bit in each direction changes value once per round-trip time (RTT).
An on-path observer can observe the time difference between edges An on-path observer can observe the time difference between edges
(changes from 1 to 0 or 0 to 1) in the spin bit signal in a single (changes from 1 to 0 or 0 to 1) in the spin bit signal in a single
direction to measure one sample of end-to-end RTT. direction to measure one sample of end-to-end RTT. This mechanism
follows the principles of protocol measurability laid out in [IPIM].
Note that this measurement, as with passive RTT measurement for TCP, Note that this measurement, as with passive RTT measurement for TCP,
includes any transport protocol delay (e.g., delayed sending of includes any transport protocol delay (e.g., delayed sending of
acknowledgements) and/or application layer delay (e.g., waiting for a acknowledgements) and/or application layer delay (e.g., waiting for a
response to be generated). It therefore provides devices on path a response to be generated). It therefore provides devices on path a
good instantaneous estimate of the RTT as experienced by the good instantaneous estimate of the RTT as experienced by the
application. A simple linear smoothing or moving minimum filter can application.
be applied to the stream of RTT information to get a more stable
estimate.
However, application-limited and flow-control-limited senders can However, application-limited and flow-control-limited senders can
have application and transport layer delay, respectively, that are have application and transport layer delay, respectively, that are
much greater than network RTT. When the sender is application- much greater than network RTT. When the sender is application-
limited and e.g. only sends small amount of periodic application limited and e.g. only sends small amount of periodic application
traffic, where that period is longer than the RTT, measuring the spin traffic, where that period is longer than the RTT, measuring the spin
bit provides information about the application period, not the bit provides information about the application period, not the
network RTT. network RTT.
Since the spin bit logic at each endpoint considers only samples from Since the spin bit logic at each endpoint considers only samples from
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An on-path observer that can see traffic in both directions (from An on-path observer that can see traffic in both directions (from
client to server and from server to client) can also use the spin bit client to server and from server to client) can also use the spin bit
to measure "upstream" and "downstream" component RTT; i.e, the to measure "upstream" and "downstream" component RTT; i.e, the
component of the end-to-end RTT attributable to the paths between the component of the end-to-end RTT attributable to the paths between the
observer and the server and the observer and the client, observer and the server and the observer and the client,
respectively. It does this by measuring the delay between a spin respectively. It does this by measuring the delay between a spin
edge observed in the upstream direction and that observed in the edge observed in the upstream direction and that observed in the
downstream direction, and vice versa. downstream direction, and vice versa.
Raw RTT samples generated using these techniques can be processed in
various ways to generate useful network performance metrics. A
simple linear smoothing or moving minimum filter can be applied to
the stream of RTT samples to get a more stable estimate of
application-experienced RTT. RTT samples measured from the spin bit
can also be used to generate RTT distribution information, including
minimum RTT (which approximates network RTT over longer time windows)
and RTT variance (which approximates jitter as seen by the
application).
4. Specific Network Management Tasks 4. Specific Network Management Tasks
In this section, we review specific network management and In this section, we review specific network management and
measurement techniques and how QUIC's design impacts them. measurement techniques and how QUIC's design impacts them.
4.1. Stateful Treatment of QUIC Traffic 4.1. Stateful Treatment of QUIC Traffic
Stateful treatment of QUIC traffic (e.g., at a firewall or NAT Stateful treatment of QUIC traffic (e.g., at a firewall or NAT
middlebox) is possible through QUIC traffic and version middlebox) is possible through QUIC traffic and version
identification (Section 3.1) and observation of the handshake for identification (Section 3.1) and observation of the handshake for
connection confirmation (Section 3.2). The lack of any visible end- connection confirmation (Section 3.2). The lack of any visible end-
of-flow signal (Section 3.5) means that this state must be purged of-flow signal (Section 3.6) means that this state must be purged
either through timers or through least-recently-used eviction, either through timers or through least-recently-used eviction,
depending on application requirements. depending on application requirements.
[RFC4787] recommends a 2 minute timeout interval for UDP. However, [RFC4787] requires a timeout that is not less than 2 minutes for most
timers can be lower, in the range of 15 to 30 seconds. In contrast, UDP traffic. However, in pratice, timers are often lower, in the
[RFC5382] recommends a timeout of more than 2 hours for TCP, given range of 15 to 30 seconds. In contrast, [RFC5382] recommends a
that TCP is a connection-oriented protocol with well-defined closure timeout of more than 2 hours for TCP, given that TCP is a connection-
semantics. For network devices that are QUIC-aware, it is oriented protocol with well-defined closure semantics. For network
recommended to also use longer timeouts for QUIC traffic, as QUIC is devices that are QUIC-aware, it is recommended to also use longer
connection-oriented. As such, a handshake packet from the server timeouts for QUIC traffic, as QUIC is connection-oriented. As such,
indicates the willingness of the server to communicate with the a handshake packet from the server indicates the willingness of the
client. server to communicate with the client.
The QUIC header optionally contains a connection ID which can be used The QUIC header optionally contains a connection ID which can be used
as additional entropy beyond the 5-tuple, if needed. The QUIC as additional entropy beyond the 5-tuple, if needed. The QUIC
handshake needs to be observed in order to understand whether the handshake needs to be observed in order to understand whether the
connection ID is present and what length it has. However, connection connection ID is present and what length it has. However, connection
IDs may be renegotiated during a connection, and this renegotiation IDs may be renegotiated during after the handshake, and this
is not visible to the path. Keying state off the connection ID may renegotiation is not visible to the path. Using the connection ID as
therefore cause undetectable and unrecoverable loss of state in the a flow key field for stateful treatment of flows may therefore cause
middle of a connection. Use of connection ID specifically undetectable and unrecoverable loss of state in the middle of a
discouraged for NAT applications. connection. Use of connection IDs is specifically discouraged for
NAT applications.
4.2. Passive Network Performance Measurement and Troubleshooting 4.2. Passive Network Performance Measurement and Troubleshooting
Limited RTT measurement is possible by passive observation of QUIC Limited RTT measurement is possible by passive observation of QUIC
traffic; see Section 3.7. No passive measurement of loss is possible traffic; see Section 3.8. No passive measurement of loss is possible
with the present wire image. Extremely limited observation of with the present wire image. Extremely limited observation of
upstream congestion may be possible via the observation of CE upstream congestion may be possible via the observation of CE
markings on ECN-enabled QUIC traffic. markings on ECN-enabled QUIC traffic.
4.3. Server Cooperation with Load Balancers 4.3. Server Cooperation with Load Balancers
In the case of content distribution networking architectures In the case of content distribution networking architectures
including load balancers, the connection ID provides a way for the including load balancers, the connection ID provides a way for the
server to signal information about the desired treatment of a flow to server to signal information about the desired treatment of a flow to
the load balancers. Guidance on assigning connection IDs is given in the load balancers. Guidance on assigning connection IDs is given in
skipping to change at page 21, line 35 skipping to change at page 22, line 44
The recommended way to police QUIC packets is to either drop them all The recommended way to police QUIC packets is to either drop them all
or to throttle them based on the hash of the UDP datagram's source or to throttle them based on the hash of the UDP datagram's source
and destination addresses, blocking a portion of the hash space that and destination addresses, blocking a portion of the hash space that
corresponds to the fraction of UDP traffic one wishes to drop. When corresponds to the fraction of UDP traffic one wishes to drop. When
the handshake is blocked, QUIC-capable applications may failover to the handshake is blocked, QUIC-capable applications may failover to
TCP (at least applications using well-known UDP ports). However, TCP (at least applications using well-known UDP ports). However,
blindly blocking a significant fraction of QUIC packets will allow blindly blocking a significant fraction of QUIC packets will allow
many QUIC handshakes to complete, preventing a TCP failover, but the many QUIC handshakes to complete, preventing a TCP failover, but the
connections will suffer from severe packet loss. connections will suffer from severe packet loss.
4.6. Distinguishing Acknowledgment traffic 4.6. Handling ICMP Messages
Some deployed in-network functions distinguish pure-acknowledgment Datagram Packetization Layer PMTU Discovery (PLPMTUD) can be used by
(ACK) packets from packets carrying upper-layer data in order to QUIC to probe for the supported PMTU. PLPMTUD optionally uses ICMP
attempt to enhance performance, for example by queueing ACKs messages (e.g., IPv6 Packet Too Big messages). Given known attacks
differently or manipulating ACK signaling. Distinguishing ACK with the use of ICMP messages, the use of PLPMTUD in QUIC has been
packets is trivial in TCP, but not supported by QUIC, since designed to safely use but not rely on receiving ICMP feedback (see
acknowledgment signaling is carried inside QUIC's encrypted payload, Section 14.2.1. of [QUIC-TRANSPORT]).
and ACK manipulation is impossible. Specifically, heuristics
attempting to distinguish ACK-only packets from payload-carrying Networks are recommended to forward these ICMP messages and retain as
packets based on packet size are likely to fail, and are emphatically much of the original packet as possible without exceeding the minimum
NOT RECOMMENDED. MTU for the IP version when generating ICMP messages as recommended
in [RFC1812] and [RFC4443].
4.7. Quality of Service handling and ECMP 4.7. Quality of Service handling and ECMP
It is expected that any QoS handling in the network, e.g. based on It is expected that any QoS handling in the network, e.g. based on
use of DiffServ Code Points (DSCPs) [RFC2475] as well as Equal-Cost use of DiffServ Code Points (DSCPs) [RFC2475] as well as Equal-Cost
Multi-Path (ECMP) routing, is applied on a per flow-basis (and not Multi-Path (ECMP) routing, is applied on a per flow-basis (and not
per-packet) and as such that all packets belonging to the same QUIC per-packet) and as such that all packets belonging to the same QUIC
connection get uniform treatment. Using ECMP to distribute packets connection get uniform treatment. Using ECMP to distribute packets
from a single flow across multiple network paths or any other non- from a single flow across multiple network paths or any other non-
uniform treatment of packets belong to the same connection could uniform treatment of packets belong to the same connection could
skipping to change at page 23, line 30 skipping to change at page 24, line 34
Imagine two clients behind a NAT that are sharing the same public IP Imagine two clients behind a NAT that are sharing the same public IP
address and port. The NAT is differentiating them using the incoming address and port. The NAT is differentiating them using the incoming
Connection ID. If one client secretly changes its connection ID, Connection ID. If one client secretly changes its connection ID,
there will be no mapping for the NAT, and the connection will there will be no mapping for the NAT, and the connection will
suddenly break. suddenly break.
QUIC is deliberately designed to fail rather than persist when the QUIC is deliberately designed to fail rather than persist when the
network cannot support its operation. For HTTP/3, this extends to network cannot support its operation. For HTTP/3, this extends to
recommending a fallback to TCP-based versions of HTTP rather than recommending a fallback to TCP-based versions of HTTP rather than
persisting with a QUIC connection that might be unstable. And persisting with a QUIC connection that might be unstable. And
[I-D.ietf-quic-applicability] recommends TCP fallback for other [QUIC-APPLICABILITY] recommends TCP fallback for other protocols on
protocols on the basis that this is preferable to sudden connection the basis that this is preferable to sudden connection errors and
errors and time outs. Furthermore, wide deployment of NATs with this time outs. Furthermore, wide deployment of NATs with this behavior
behavior hinders the use of QUIC's migration function, which relies hinders the use of QUIC's migration function, which relies on the
on the ability to change the connection ID any time during the ability to change the connection ID any time during the lifetime of a
lifetime of a QUIC connection. QUIC connection.
It is possible, in principle, to encode the client's identity in a It is possible, in principle, to encode the client's identity in a
connection ID using the techniques described in [QUIC_LB] and connection ID using the techniques described in [QUIC_LB] and
explicit coordination with the NAT. However, this implies that the explicit coordination with the NAT. However, this implies that the
client shares configuration with the NAT, which might be logistically client shares configuration with the NAT, which might be logistically
difficult. This adds administrative overhead while not resolving the difficult. This adds administrative overhead while not resolving the
case where a client migrates to a point behind the NAT. case where a client migrates to a point behind the NAT.
Note that multiplexing connection IDs over a single port anyway Note that multiplexing connection IDs over a single port anyway
violates the best common practice to avoid "port overloading" as violates the best common practice to avoid "port overloading" as
skipping to change at page 26, line 11 skipping to change at page 27, line 21
Special thanks to Martin Thomson and Martin Duke for the detailed Special thanks to Martin Thomson and Martin Duke for the detailed
reviews and feedback. reviews and feedback.
This work is partially supported by the European Commission under This work is partially supported by the European Commission under
Horizon 2020 grant agreement no. 688421 Measurement and Architecture Horizon 2020 grant agreement no. 688421 Measurement and Architecture
for a Middleboxed Internet (MAMI), and by the Swiss State Secretariat for a Middleboxed Internet (MAMI), and by the Swiss State Secretariat
for Education, Research, and Innovation under contract no. 15.0268. for Education, Research, and Innovation under contract no. 15.0268.
This support does not imply endorsement. This support does not imply endorsement.
9. Appendix 9. References
9.1. Normative References
[QUIC-TLS] Thomson, M. and S. Turner, "Using TLS to Secure QUIC",
Work in Progress, Internet-Draft, draft-ietf-quic-tls-34,
14 January 2021,
<https://tools.ietf.org/html/draft-ietf-quic-tls-34>.
[QUIC-TRANSPORT]
Iyengar, J. and M. Thomson, "QUIC: A UDP-Based Multiplexed
and Secure Transport", Work in Progress, Internet-Draft,
draft-ietf-quic-transport-34, 14 January 2021,
<https://tools.ietf.org/html/draft-ietf-quic-transport-
34>.
9.2. Informative References
[DOTS-ARCH]
Mortensen, A., Reddy, T., Andreasen, F., Teague, N., and
R. Compton, "DDoS Open Threat Signaling (DOTS)
Architecture", Work in Progress, Internet-Draft, draft-
ietf-dots-architecture-18, 6 March 2020,
<https://tools.ietf.org/html/draft-ietf-dots-architecture-
18>.
[IPIM] Allman, M., Beverly, R., and B. Trammell, "In-Protocol
Internet Measurement (arXiv preprint 1612.02902)", 9
December 2016, <https://arxiv.org/abs/1612.02902>.
[QUIC-APPLICABILITY]
Kuehlewind, M. and B. Trammell, "Applicability of the QUIC
Transport Protocol", Work in Progress, Internet-Draft,
draft-ietf-quic-applicability-09, 22 January 2021,
<https://tools.ietf.org/html/draft-ietf-quic-
applicability-09>.
[QUIC-HTTP]
Bishop, M., "Hypertext Transfer Protocol Version 3
(HTTP/3)", Work in Progress, Internet-Draft, draft-ietf-
quic-http-34, 2 February 2021,
<https://tools.ietf.org/html/draft-ietf-quic-http-34>.
[QUIC-INVARIANTS]
Thomson, M., "Version-Independent Properties of QUIC",
Work in Progress, Internet-Draft, draft-ietf-quic-
invariants-13, 14 January 2021,
<https://tools.ietf.org/html/draft-ietf-quic-invariants-
13>.
[QUIC-RECOVERY]
Iyengar, J. and I. Swett, "QUIC Loss Detection and
Congestion Control", Work in Progress, Internet-Draft,
draft-ietf-quic-recovery-34, 14 January 2021,
<https://tools.ietf.org/html/draft-ietf-quic-recovery-34>.
[QUIC_LB] Duke, M. and N. Banks, "QUIC-LB: Generating Routable QUIC
Connection IDs", Work in Progress, Internet-Draft, draft-
ietf-quic-load-balancers-06, 4 February 2021,
<https://tools.ietf.org/html/draft-ietf-quic-load-
balancers-06>.
[RFC1812] Baker, F., Ed., "Requirements for IP Version 4 Routers",
RFC 1812, DOI 10.17487/RFC1812, June 1995,
<https://www.rfc-editor.org/rfc/rfc1812>.
[RFC2475] Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z.,
and W. Weiss, "An Architecture for Differentiated
Services", RFC 2475, DOI 10.17487/RFC2475, December 1998,
<https://www.rfc-editor.org/rfc/rfc2475>.
[RFC3022] Srisuresh, P. and K. Egevang, "Traditional IP Network
Address Translator (Traditional NAT)", RFC 3022,
DOI 10.17487/RFC3022, January 2001,
<https://www.rfc-editor.org/rfc/rfc3022>.
[RFC4443] Conta, A., Deering, S., and M. Gupta, Ed., "Internet
Control Message Protocol (ICMPv6) for the Internet
Protocol Version 6 (IPv6) Specification", STD 89,
RFC 4443, DOI 10.17487/RFC4443, March 2006,
<https://www.rfc-editor.org/rfc/rfc4443>.
[RFC4787] Audet, F., Ed. and C. Jennings, "Network Address
Translation (NAT) Behavioral Requirements for Unicast
UDP", BCP 127, RFC 4787, DOI 10.17487/RFC4787, January
2007, <https://www.rfc-editor.org/rfc/rfc4787>.
[RFC4937] Arberg, P. and V. Mammoliti, "IANA Considerations for PPP
over Ethernet (PPPoE)", RFC 4937, DOI 10.17487/RFC4937,
June 2007, <https://www.rfc-editor.org/rfc/rfc4937>.
[RFC5382] Guha, S., Ed., Biswas, K., Ford, B., Sivakumar, S., and P.
Srisuresh, "NAT Behavioral Requirements for TCP", BCP 142,
RFC 5382, DOI 10.17487/RFC5382, October 2008,
<https://www.rfc-editor.org/rfc/rfc5382>.
[RFC6066] Eastlake 3rd, D., "Transport Layer Security (TLS)
Extensions: Extension Definitions", RFC 6066,
DOI 10.17487/RFC6066, January 2011,
<https://www.rfc-editor.org/rfc/rfc6066>.
[RFC7301] Friedl, S., Popov, A., Langley, A., and E. Stephan,
"Transport Layer Security (TLS) Application-Layer Protocol
Negotiation Extension", RFC 7301, DOI 10.17487/RFC7301,
July 2014, <https://www.rfc-editor.org/rfc/rfc7301>.
[RFC7605] Touch, J., "Recommendations on Using Assigned Transport
Port Numbers", BCP 165, RFC 7605, DOI 10.17487/RFC7605,
August 2015, <https://www.rfc-editor.org/rfc/rfc7605>.
[TLS-ESNI] Rescorla, E., Oku, K., Sullivan, N., and C. A. Wood, "TLS
Encrypted Client Hello", Work in Progress, Internet-Draft,
draft-ietf-tls-esni-09, 16 December 2020,
<https://tools.ietf.org/html/draft-ietf-tls-esni-09>.
[TMA-QOF] Trammell, B., Gugelmann, D., and N. Brownlee, "Inline Data
Integrity Signals for Passive Measurement (in Proc. TMA
2014)", April 2014.
[WIRE-IMAGE]
Trammell, B. and M. Kuehlewind, "The Wire Image of a
Network Protocol", RFC 8546, DOI 10.17487/RFC8546, April
2019, <https://www.rfc-editor.org/rfc/rfc8546>.
Appendix A. Appendix
This appendix uses the following conventions: array[i] - one byte at This appendix uses the following conventions: array[i] - one byte at
index i of array array[i:j] - subset of array starting with index i index i of array array[i:j] - subset of array starting with index i
(inclusive) up to j-1 (inclusive) array[i:] - subset of array (inclusive) up to j-1 (inclusive) array[i:] - subset of array
starting with index i (inclusive) up to the end of the array starting with index i (inclusive) up to the end of the array
9.1. Distinguishing IETF QUIC and Google QUIC Versions A.1. Distinguishing IETF QUIC and Google QUIC Versions
This section contains algorithms that allows parsing versions from This section contains algorithms that allows parsing versions from
both Google QUIC and IETF QUIC. These mechanisms will become both Google QUIC and IETF QUIC. These mechanisms will become
irrelevant when IETF QUIC is fully deployed and Google QUIC is irrelevant when IETF QUIC is fully deployed and Google QUIC is
deprecated. deprecated.
Note that other than this appendix, nothing in this document applies Note that other than this appendix, nothing in this document applies
to Google QUIC. And the purpose of this appendix is merely to to Google QUIC. And the purpose of this appendix is merely to
distinguish IETF QUIC from any versions of Google QUIC. distinguish IETF QUIC from any versions of Google QUIC.
skipping to change at page 27, line 29 skipping to change at page 31, line 29
} }
if (first_byte_bit5) { if (first_byte_bit5) {
version = packet[9:13] version = packet[9:13]
} else { } else {
version = packet[5:9] version = packet[5:9]
} }
} else { } else {
abort("Packet without version") abort("Packet without version")
} }
9.2. Extracting the CRYPTO frame A.2. Extracting the CRYPTO frame
counter = 0 counter = 0
while (payload[counter] == 0) { while (payload[counter] == 0) {
counter += 1 counter += 1
} }
first_nonzero_payload_byte = payload[counter] first_nonzero_payload_byte = payload[counter]
fnz_payload_byte_bit3 = ((first_nonzero_payload_byte & 0x20) != 0) fnz_payload_byte_bit3 = ((first_nonzero_payload_byte & 0x20) != 0)
if (first_nonzero_payload_byte != 0x06) { if (first_nonzero_payload_byte != 0x06) {
abort("Unexpected frame") abort("Unexpected frame")
} }
skipping to change at page 28, line 28 skipping to change at page 32, line 28
if ((payload[counter] & 0xc0) == 0) { if ((payload[counter] & 0xc0) == 0) {
crypto_data_length = payload[counter] crypto_data_length = payload[counter]
counter += 1 counter += 1
} else { } else {
crypto_data_length = payload[counter:counter+2] crypto_data_length = payload[counter:counter+2]
counter += 2 counter += 2
} }
crypto_data = payload[counter:counter+crypto_data_length] crypto_data = payload[counter:counter+crypto_data_length]
ParseTLS(crypto_data) ParseTLS(crypto_data)
10. References
10.1. Normative References
[QUIC-TLS] Thomson, M. and S. Turner, "Using TLS to Secure QUIC",
Work in Progress, Internet-Draft, draft-ietf-quic-tls-34,
14 January 2021, <http://www.ietf.org/internet-drafts/
draft-ietf-quic-tls-34.txt>.
[QUIC-TRANSPORT]
Iyengar, J. and M. Thomson, "QUIC: A UDP-Based Multiplexed
and Secure Transport", Work in Progress, Internet-Draft,
draft-ietf-quic-transport-34, 14 January 2021,
<http://www.ietf.org/internet-drafts/draft-ietf-quic-
transport-34.txt>.
10.2. Informative References
[Ding2015] Ding, H. and M. Rabinovich, "TCP Stretch Acknowledgments
and Timestamps - Findings and Impliciations for Passive
RTT Measurement (ACM Computer Communication Review)", July
2015, <http://www.sigcomm.org/sites/default/files/ccr/
papers/2015/July/0000000-0000002.pdf>.
[DOTS-ARCH]
Mortensen, A., Reddy.K, T., Andreasen, F., Teague, N., and
R. Compton, "Distributed-Denial-of-Service Open Threat
Signaling (DOTS) Architecture", Work in Progress,
Internet-Draft, draft-ietf-dots-architecture-18, 6 March
2020, <http://www.ietf.org/internet-drafts/draft-ietf-
dots-architecture-18.txt>.
[I-D.ietf-quic-applicability]
Kuehlewind, M. and B. Trammell, "Applicability of the QUIC
Transport Protocol", Work in Progress, Internet-Draft,
draft-ietf-quic-applicability-08, 2 November 2020,
<http://www.ietf.org/internet-drafts/draft-ietf-quic-
applicability-08.txt>.
[IPIM] Allman, M., Beverly, R., and B. Trammell, "In-Protocol
Internet Measurement (arXiv preprint 1612.02902)", 9
December 2016, <https://arxiv.org/abs/1612.02902>.
[QUIC-APPLICABILITY]
Kuehlewind, M. and B. Trammell, "Applicability of the QUIC
Transport Protocol", Work in Progress, Internet-Draft,
draft-ietf-quic-applicability-08, 2 November 2020,
<http://www.ietf.org/internet-drafts/draft-ietf-quic-
applicability-08.txt>.
[QUIC-HTTP]
Bishop, M., "Hypertext Transfer Protocol Version 3
(HTTP/3)", Work in Progress, Internet-Draft, draft-ietf-
quic-http-33, 15 December 2020, <http://www.ietf.org/
internet-drafts/draft-ietf-quic-http-33.txt>.
[QUIC-INVARIANTS]
Thomson, M., "Version-Independent Properties of QUIC",
Work in Progress, Internet-Draft, draft-ietf-quic-
invariants-13, 14 January 2021, <http://www.ietf.org/
internet-drafts/draft-ietf-quic-invariants-13.txt>.
[QUIC_LB] Duke, M. and N. Banks, "QUIC-LB: Generating Routable QUIC
Connection IDs", Work in Progress, Internet-Draft, draft-
ietf-quic-load-balancers-05, 30 October 2020,
<http://www.ietf.org/internet-drafts/draft-ietf-quic-load-
balancers-05.txt>.
[RFC2475] Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z.,
and W. Weiss, "An Architecture for Differentiated
Services", RFC 2475, DOI 10.17487/RFC2475, December 1998,
<https://www.rfc-editor.org/info/rfc2475>.
[RFC3022] Srisuresh, P. and K. Egevang, "Traditional IP Network
Address Translator (Traditional NAT)", RFC 3022,
DOI 10.17487/RFC3022, January 2001,
<https://www.rfc-editor.org/info/rfc3022>.
[RFC4787] Audet, F., Ed. and C. Jennings, "Network Address
Translation (NAT) Behavioral Requirements for Unicast
UDP", BCP 127, RFC 4787, DOI 10.17487/RFC4787, January
2007, <https://www.rfc-editor.org/info/rfc4787>.
[RFC4937] Arberg, P. and V. Mammoliti, "IANA Considerations for PPP
over Ethernet (PPPoE)", RFC 4937, DOI 10.17487/RFC4937,
June 2007, <https://www.rfc-editor.org/info/rfc4937>.
[RFC5382] Guha, S., Ed., Biswas, K., Ford, B., Sivakumar, S., and P.
Srisuresh, "NAT Behavioral Requirements for TCP", BCP 142,
RFC 5382, DOI 10.17487/RFC5382, October 2008,
<https://www.rfc-editor.org/info/rfc5382>.
[RFC6066] Eastlake 3rd, D., "Transport Layer Security (TLS)
Extensions: Extension Definitions", RFC 6066,
DOI 10.17487/RFC6066, January 2011,
<https://www.rfc-editor.org/info/rfc6066>.
[RFC6928] Chu, J., Dukkipati, N., Cheng, Y., and M. Mathis,
"Increasing TCP's Initial Window", RFC 6928,
DOI 10.17487/RFC6928, April 2013,
<https://www.rfc-editor.org/info/rfc6928>.
[RFC7301] Friedl, S., Popov, A., Langley, A., and E. Stephan,
"Transport Layer Security (TLS) Application-Layer Protocol
Negotiation Extension", RFC 7301, DOI 10.17487/RFC7301,
July 2014, <https://www.rfc-editor.org/info/rfc7301>.
[RFC7605] Touch, J., "Recommendations on Using Assigned Transport
Port Numbers", BCP 165, RFC 7605, DOI 10.17487/RFC7605,
August 2015, <https://www.rfc-editor.org/info/rfc7605>.
[TLS-ESNI] Rescorla, E., Oku, K., Sullivan, N., and C. Wood, "TLS
Encrypted Client Hello", Work in Progress, Internet-Draft,
draft-ietf-tls-esni-09, 16 December 2020,
<http://www.ietf.org/internet-drafts/draft-ietf-tls-esni-
09.txt>.
[TMA-QOF] Trammell, B., Gugelmann, D., and N. Brownlee, "Inline Data
Integrity Signals for Passive Measurement (in Proc. TMA
2014)", April 2014.
[WIRE-IMAGE]
Trammell, B. and M. Kuehlewind, "The Wire Image of a
Network Protocol", RFC 8546, DOI 10.17487/RFC8546, April
2019, <https://www.rfc-editor.org/info/rfc8546>.
Authors' Addresses Authors' Addresses
Mirja Kuehlewind Mirja Kuehlewind
Ericsson Ericsson
Email: mirja.kuehlewind@ericsson.com Email: mirja.kuehlewind@ericsson.com
Brian Trammell Brian Trammell
Google Google
Gustav-Gull-Platz 1 Gustav-Gull-Platz 1
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