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

QUIC Packets are carried in UDP datagrams and exchanged for communication of QUIC endpoints . 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 . 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 . This document specifies several new IPFIX Information Elements (IEs) within the "IPFIX Information Elements" registry for purposes of getting QUIC related information. These IEs are used to export the unencrypted parameters of QUIC Header in QUIC packet.

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 when, and only when, they appear in all capitals, as shown here. This document makes use of the terms defined in and . The following terms are used as defined in : IPFIX IPFIX Information Elements The following terms are used as defined in : QUIC Endpoint Server QUIC packet Connection ID

This section specifies the new IPFIX QUIC IEs. 8-bit flag defined in the QUIC Header (Section 17.2 and 17.3 of ), 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. 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. 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. 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.

The IPFIX IEs listed in the Section 3, forwardingStatus (89) and some existing counter information 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?

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

This document requests IANA to add new IPFIX QUIC IEs to the "IPFIX Information Elements" registry available at . Table 1 lists the new IPFIX QUIC IEs:

Name:: quicHeaderFlag

ElementID:: TBD1

Description:: The 8-bit flag defined in the QUIC Header (Section 17.2 and 17.3 of ). The meanings of the flag are provided in the first byte of the QUIC Header Packet .

Abstract Data Type:: unsigned8

Data Type Semantics:: flags

Additional Information:: See RFC9000 for the QUIC Header first byte specification.

Reference:: [this document]

Name:: quicVersion

ElementID:: TBD2

Description:: 32-bit unsigned integer defining the number of Version, which is in use and negotiation. Its values are provided in the "QUIC Versions" IANA registry.

Abstract Data Type:: unsigned32

Data Type Semantics:: default

Additional Information:: See the assignments in the "QUIC Versions" IANA registry at https://www.iana.org/assignments/quic/quic.xhtml#quic-versions. See also RFC9000 for the QUIC Versions specification.

Reference:: [this document]

Name:: quicDestinationConnectionID

ElementID:: TBD3

Description:: The Destination Connection ID as defined in Section 7.2 of as a series of octets in IPFIX. In QUIC version 1, this value MUST NOT exceed 20 bytes.

Abstract Data Type:: octetArray

Data Type Semantics:: default

Additional Information:: See Section 7.2 of for more details about The Destination Connection ID.

Reference:: [this document]

Name:: quicSourceConnectionID

ElementID:: TBD4

Description:: The Source Connection ID as defined in Section 7.2 of as a series of octets in IPFIX. In QUIC version 1, this value MUST NOT exceed 20 bytes.

Abstract Data Type:: octetArray

Data Type Semantics:: default

Additional Information:: See Section 7.2 of for more details about The Source Connection ID.

Reference:: [this document]

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.