| Internet-Draft | NETCONF over QUIC | October 2024 |
| Dai, et al. | Expires 24 April 2025 | [Page] |
This document specifies how to use QUIC as a secure transport for exchanging Network Configuration Protocol (NETCONF) messages. QUIC provides encryption properties similar to TLS, while eliminating TCP head-of-line blocking issues and also providing more loss detection and congestion control than UDP. NETCONF over QUIC has privacy properties similar to NETCONF over TLS specified in [I-D.ietf-netconf-over-tls13].¶
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The Network Configuration Protocol (NETCONF) [RFC6241] defines a mechanism through which the configuration of network devices can be installed, manipulated, and deleted.¶
NETCONF can be conceptually partitioned into four layers: content, operation, message and security transport layers.¶
The Secure Transport layer provides a communication path between the client and server. NETCONF can be layered over any transport protocol that provides a set of basic requirements, such as:¶
The NETCONF protocol is not bound to any particular transport protocol, but allows a mapping to define how it can be implemented over any specific protocol.¶
However, because of the connection-oriented feature, almost all of the current secure transport protocols used by NETCONF are TCP based. As is well known, TCP has some shortcomings such as head-of-line blocking.¶
QUIC ([RFC9000][RFC9001]) conforms to the above requirements, therefore is also an appropriate transport protocol for NETCONF. Moreover, QUIC provides the following additional benefits not present in the other NETCONF transports:¶
Therefore, QUIC is a proper transport protocol for the secure transport layer of NETCONF. This document specifies how to use QUIC as the secure transport protocol for NETCONF.¶
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119].¶
QUIC connections are established as described in [RFC9000]. During connection establishment, NETCONF over QUIC support is indicated by selecting the ALPN token as listed in the IANA sectionSection 7 in the crypto handshake.¶
The typical QUIC connection termination process is described in [RFC9000]¶
When a NETCONF session is implemented based on a QUIC connection, the idle timeout should be set appropriately in order to keep the QUIC connection persistent even if the NETCONF session is idle. In some cases, disabling it may be a possible option.¶
When a NETCONF server receives a <close-session> request, it will gracefully close the NETCONF session. The server SHOULD close the associated QUIC connection.¶
When a NETCONF entity receives a <kill-session> request for an open session, it SHOULD close the associated QUIC connection.¶
When a NETCONF entity is detecting the interruption of the QUIC connection, it SHOULD send a <close-session> request to the peer NETCONF entity.¶
When a stateless reset event occurs, nothing needs to be done by either the client or the server.¶
[RFC6241] specifies protocol layers of NETCONF as shown below.¶
Layer Example
+-------------+ +-----------------+ +----------------+
(4) | Content | | Configuration | | Notification |
| | | data | | data |
+-------------+ +-----------------+ +----------------+
| | |
+-------------+ +-----------------+ |
(3) | Operations | | <edit-config> | |
| | | | |
+-------------+ +-----------------+ |
| | |
+-------------+ +-----------------+ +----------------+
(2) | Messages | | <rpc>, | | <notification> |
| | | <rpc-reply> | | |
+-------------+ +-----------------+ +----------------+
| | |
+-------------+ +-----------------------------------------+
(1) | Secure | | SSH, TLS, BEEP/TLS, SOAP/HTTP/TLS, ... |
| Transport | | |
+-------------+ +-----------------------------------------+
Figure 1 shows that there are two kinds of main data flow exchanged between client and server:¶
The two kinds of data flow need to be mapped into QUIC streams.¶
QUIC Streams provide a lightweight, ordered byte-stream abstraction to an application. Streams can be unidirectional or bidirectional meanwhile streams can be initiated by either the client or the server. Unidirectional streams carry data in one direction: from the initiator of the stream to its peer. Bidirectional streams allow for data to be sent in both directions.¶
QUIC uses Stream ID to identify the stream. The least significant bit (0x1) of the stream ID identifies the initiator of the stream. The second least significant bit (0x2) of the stream ID distinguishes between bidirectional streams (with the bit set to 0) and unidirectional streams. Table 1 describes the four types of streams and this table can also be seen from [RFC9000].¶
| Bits | Stream Type |
|---|---|
| 0x0 | Client-Initiated, Bidirectional |
| 0x1 | Server-Initiated, Bidirectional |
| 0x2 | Client-Initiated, Unidirectional |
| 0x3 | Server-Initiated, Unidirectional |
NETCONF protocol uses an RPC-based communication model. So, the configuration data from client to server is exchanged based on '<rpc>' (the server initiating) and '<rpc-reply>' (sent by the server) and so on. So the messages used to exchange configuration data MUST be mapped into one or more bidirectional stream whose stream type is 0x0 according to the above table.¶
There are some notification data exchanged between the client and the server. Notification is an server initiated message indicating that a certain event has been recognized by the server.¶
Notification messages are initiated by the server and no reply is needed from the client. So the messages used to exchange configuration data SHOULD be mapped into one unidirectional stream whose stream type is 0x3 according to the above table.¶
NETCONF over QUIC uses QUIC which uses TLS version 1.3 or greater. Therefore, the TLS handshake process can be used for endpoint authentication.¶
A third-party authentication mechanism can also be used for endpoint authentication, such as a TLS client certificate.¶
The security considerations described throughout [RFC5246] and [RFC6241] apply here as well. This document does not require to support third-party authentication (e.g., backend Authentication, Authorization, and Accounting (AAA) servers) due to the fact that TLS does not specify this way of authentication and that NETCONF depends on the transport protocol for the authentication service. If third-party authentication is needed, TLS client certificates, BEEP or SSH transport can be used. Especially TLS client certificates are recommended to be used here.¶
An attacker might be able to inject arbitrary NETCONF messages via some application that does not carefully check exchanged messages deliberately insert the delimiter sequence in a NETCONF message to create a DoS attack. Hence, applications and NETCONF APIs MUST ensure that the delimiter sequence defined in Section 2.1 never appears in NETCONF messages; otherwise, those messages can be dropped, garbled, or misinterpreted.¶
If invalid data or malformed messages are encountered, a robust implementation of this document MUST silently discard the message without further processing and then stop the NETCONF session.¶
Finally, this document does not introduce any new security considerations compared to [RFC6242].¶
This document creates a new registration for the identification of NETCONF over QUIC in the "Application Layer Protocol Negotiation (ALPN) Protocol IDs registry established in [RFC7301].¶
The "noq" string identifies NETCONF over QUIC:¶
In addition, it is requested for IANA to reserve a UDP port TBD for 'NETCONF over QUIC'.¶
The authors would like to acknowledge all contributors including Huaimo Chen, Lifen Zhou et al. for their beneficial comments.¶