Internet-Draft | YANG VRRP | September 2024 |
Lindem, et al. | Expires 31 March 2025 | [Page] |
This document describes a YANG data model for the Virtual Router Redundancy Protocol (VRRP). Both versions 2 and 3 of VRRP are covered.¶
The VRRP terminology has been updated conform to inclusive language guidelines for IETF technologies. To avoid YANG non-backward compatible change restrictions, the YANG module will have desigination ietf-vrrp-2.yang rather than ietf-vrrp.yang.¶
This document obsoletes RFC 8347.¶
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Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at https://datatracker.ietf.org/drafts/current/.¶
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This document introduces a YANG data model [RFC6020] [RFC7950] for the Virtual Router Redundancy Protocol (VRRP) [RFC3768] [RFC9568]. VRRP provides higher resiliency by specifying an election protocol that dynamically assigns responsibility for a virtual router to one of the VRRP routers on a LAN.¶
The YANG module specified in this document supports both versions 2 and 3 of VRRP. VRRP version 2 (defined in [RFC3768]) supports IPv4. VRRP version 3 (defined in [RFC9568]) supports both IPv4 and IPv6.¶
The VRRP terminology has been updated conform to inclusive language guidelines for IETF technologies. To avoid YANG non-backward compatible change restrictions, the YANG module will have desigination ietf-vrrp-2.yang rather than ietf-vrrp.yang. The IETF has designated National Institute of Standards and Technology (NIST) "Guidance for NIST Staff on Using Inclusive Language in Documentary Standards" [NISTIR8366] for its inclusive language guidelines. This document obsoletes VRRP Version 3 [RFC8347].¶
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.¶
The following terms are defined in [RFC7950] and are not redefined here:¶
A simplified graphical representation of the data model is used in this document. The meaning of the symbols in these diagrams is defined in [RFC8340].¶
In this document, names of data nodes, actions, and other data model objects are often used without a prefix, as long as it is clear from the context in which YANG module each name is defined. Otherwise, names are prefixed using the standard prefix associated with the corresponding YANG module, as shown in Table 1.¶
The model covers VRRP version 2 [RFC3768] and VRRP version 3 [RFC9568]. The model is designed to be implemented on a device where VRRP version 2 or 3 is implemented. With the help of a proper management protocol, the defined model can be used to:¶
This model augments the interface data model "ietf-interfaces" [RFC8343] and the IP management model "ietf-ip" [RFC8344]. The augmentation relationships are shown as follows:¶
In the above figure, a tree node without a prefix is from the model "ietf-interfaces". A tree node with prefix "ip:" is from the model "ietf-ip". A tree node with prefix "vrrp:" is from the VRRP model specified in this document.¶
The "vrrp" container contains a list of vrrp-instance nodes, which are instantiated under an interface for a specified address family (IPv4 or IPv6).¶
Each vrrp-instance node represents a VRRP router state machine, as described in Section 6.4 of [RFC9568], providing the configuration and state information for the election process of a virtual router. The IP addresses on the augmented interface are the real addresses through which the VRRP router operates. The IPv4 or IPv6 address or addresses associated with a virtual router (described in Section 1 of [RFC9568]) are modeled as a list of IPv4 or IPv6 addresses under the vrrp-instance.¶
The model structure for the protocol configuration is as shown below:¶
The model allows the following protocol entities to be configured:¶
The model structure for the protocol states is as shown below:¶
This model conforms to the Network Management Datastore Architecture (NMDA) [RFC8342]. The operational state data is combined with the associated configuration data in the same hierarchy [RFC8407]. When protocol states are retrieved from the NMDA operational state datastore, the returned states cover all "config true" (rw) and "config false" (ro) nodes defined in the schema.¶
The model allows the retrieval of protocol states at the following levels:¶
This model defines the following VRRP-specific notifications:¶
Each notification type is used to indicate a type of VRRP state change or error occurrence:¶
VRRP new active event, indicating that a new active virtual router has been elected.¶
VRRP protocol error event for a message that fails to reach a VRRP instance to be processed.¶
VRRP virtual router error event for a message processed on a VRRP instance.¶
In addition to the notifications specified above, the mechanisms defined in [RFC8639] and [RFC8641] can be used for other general notifications. These mechanisms currently allow the user to:¶
The VRRP-2 YANG data model defined in this document has the following tree structure:¶
This module references [RFC2787], [RFC3768], [RFC9568], and [RFC6527].¶
This document registers the following namespace URI in the "IETF XML Registry" [RFC3688]:¶
This document registers the following YANG module in the "YANG Module Names" registry [RFC7950]:¶
The YANG module specified in this document defines a schema for data that is designed to be accessed via network management protocols such as NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF layer is the secure transport layer, and the mandatory-to-implement secure transport is Secure Shell (SSH) [RFC6242]. The lowest RESTCONF layer is HTTPS, and the mandatory-to-implement secure transport is TLS [RFC5246].¶
The NETCONF access control model [RFC8341] provides the means to restrict access for particular NETCONF or RESTCONF users to a preconfigured subset of all available NETCONF or RESTCONF protocol operations and content.¶
There are a number of data nodes defined in this YANG module that are writable/creatable/deletable (i.e., config true, which is the default). These data nodes may be considered sensitive or vulnerable in some network environments. Write operations (e.g., edit-config) to these data nodes without proper protection can have a negative effect on network operations. These are the subtrees and data nodes and their sensitivity/vulnerability:¶
/if:interfaces/if:interface/ip:ipv4/vrrp:vrrp/vrrp:vrrp-instance¶
/if:interfaces/if:interface/ip:ipv6/vrrp:vrrp/vrrp:vrrp-instance¶
Unauthorized access to any data node of these subtrees can adversely affect the routing subsystem of both the local device and the network. This may lead to network malfunctions, delivery of packets to inappropriate destinations, and other problems.¶
Some of the readable data nodes in this YANG module may be considered sensitive or vulnerable in some network environments. It is thus important to control read access (e.g., via get, get-config, or notification) to these data nodes. These are the subtrees and data nodes and their sensitivity/vulnerability:¶
/ietf-vrrp-2:vrrp¶
/if:interfaces/if:interface/ip:ipv4/vrrp:vrrp/vrrp:vrrp-instance¶
/if:interfaces/if:interface/ip:ipv6/vrrp:vrrp/vrrp:vrrp-instance¶
Unauthorized access to any data node of these subtrees can disclose the operational state information of VRRP on this device.¶
Thanks to Nicola Serafini for his suggestion to add effective-priority to the virtual router operational state.¶
This section contains an example of an instance data tree in JSON encoding [RFC7951], containing both configuration and state data. (This example includes "iana-if-type", which is defined in [RFC7224].)¶
The configuration instance data for Router 1 in the above figure could be as follows:¶
The corresponding operational state data for Router 1 could be as follows:¶