Export of QUIC Information in IP Flow Information Export (IPFIX)

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Table of Contents

1. Introduction

QUIC Packets are carried in UDP datagrams and exchanged for communication of QUIC endpoints [RFC9000]. A QUIC packet normally consists of a QUIC Header and a QUIC Payload.¶

QUIC Header is divided into Long Header and Short Header. Long Headers are used for packets that are sent prior to the establishment of 1-RTT keys. The Long Header contains an 8-bit Public Flag, a 32-bit QUIC Version, a variable-length Destination Connection ID, a variable-length Source Connection ID and Type-Specific field which has different content based on the Packet type. The Packet types that use the Long Header contain Version Negotiation Packet, Initial Packet, 0-RTT Packet, Handshake Packet and Retry Packet. Once 1-RTT keys are available, a sender switches to sending 1-RTT packets using the Short Header. The Short Header includes an 8-bit Public Flag, a variable-length Destination Connection ID and a Packet Number.¶

QUIC packets provide varying levels of cryptographic protection depending on their type [RFC9000]. While the entire QUIC Payload MUST be encrypted, only certain fields in the QUIC Header are protected. For details on QUIC's packet protection mechanisms, refer to Section 5 of [RFC9001].¶

This document specifies several new IPFIX Information Elements (IEs) within the "IPFIX Information Elements" registry [RFC7012] for purposes of getting QUIC related information. These IEs are used to export the unencrypted parameters of QUIC Header in QUIC packet.¶

2. Terminology

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.¶

This document makes use of the terms defined in [RFC7011] and [RFC9000].¶

The following terms are used as defined in [RFC7011]:¶

• IPFIX¶

• IPFIX Information Elements¶

The following terms are used as defined in [RFC9000]:¶

• QUIC¶

• Endpoint¶

• Server¶

• QUIC packet¶

• Connection ID¶

3. New IPFIX QUIC Information Elements

This section specifies the new IPFIX QUIC IEs.¶

quicHeaderFlag

8-bit flag defined in the QUIC Header (Section 17.2 and 17.3 of [RFC9000]), as the first byte of QUIC Packet. Base on the first four bits of the Long Header flag and the first three bits of the Short Header flag, the QUIC Packet Type can be obtained.¶

quicVersion

32-bit QUIC Version that is in use or negotiation in QUIC Long Header Packets during connection establishment. For Version Negotiation Packet, This Version is used to indicate the Supported Version, because the Version field of a Version Negotiation Packet MUST be set to 0x00000000.¶

quicDestinationConnectionID

The Destination Connection ID included in the Long Header or Short Header of QUIC Packet. The Destination Connection ID is chosen by the recipient of the packet and is used to provide consistent routing. Since the length of the Destination Connection ID is not included in 1-RTT Packet (Short Header), the Destination Connection ID of a 1-RTT Packet could be obtained by matching only if when the Destination Connection ID is known and preconfigured on the device.¶

quicSourceConnectionID

The Source Connection ID included by the Long Header of QUIC Packet. The Source Connection ID is used to set the Destination Connection ID used by the peer during connection establishment.¶

4. Sample Use Cases

The IPFIX IEs listed in the Section 3, forwardingStatus (89) [RFC7270] and some existing counter information [IANA-IPFIX] provide answers to the following questions (amongst others).¶

• How many packets are forwarded or dropped using QUIC in a network?¶

• If dropped, for which reasons?¶

• What is the type of QUIC packet?¶

• What is the QUIC version that is in use or negotiation?¶

• What is the Destination or Source Connection ID of QUIC packet?¶

• Have all the QUIC packets been fully received?¶

5. Security Considerations

There exists no extra security considerations regarding allocation of these new IPFIX IEs compared to [RFC7012].¶

6. IANA Considerations

    +============+=============================+===============+
    | Element ID | Name                        | Reference     |
    +============+=============================+===============+
    | TBD1       | quicHeaderFlag              | This document |
    +------------+-----------------------------+---------------+
    | TBD2       | quicVersion                 | This document |
    +------------+-----------------------------+---------------+
    | TBD3       | quicDestinationConnectionID | This document |
    +------------+-----------------------------+---------------+
    | TBD4       | quicSourceConnectionID      | This document |
    +------------+-----------------------------+---------------+

 Table 1: New QUIC IEs in the "IPFIX Information Elements" Registry

7. Operational Considerations

The quicDestinationConnectionID can be used to track flow path consistency, but the Destination Connection ID in the Short Header Packet lacks a length indication, making it difficult to match on intermediate devices. Therefore, the Destination Connection ID or its length must be preconfigured on the intermediate devices.¶

Authors' Addresses