RIFT Key/Value Structure and Registry
Internet-Draft draft-ietf-rift-kv-registry-04
Jordan Head, Ed.
Juniper Networks
1137 Innovation Way
Sunnyvale
CA
USA
jhead@juniper.net
Tony Przygienda
Juniper Networks
1137 Innovation Way
Sunnyvale
CA
USA
prz@juniper.net
2022
Routing Area
RIFT
rift
kv
The RIFT (Routing in Fat-Trees) protocol allows for key/value pairs to be advertised within Key-Value Topology Information Elements (KV-TIEs). The data contained within these KV-TIEs can be used for any imaginable purpose. This document defines the various Key-Types (i.e. Well-Known, OUI, and Experimental) and a method to structure corresponding values.
Requirements Language
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 asdescribed in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.
Introduction
The Routing in Fat-Trees RIFT protocol allows for key/value pairs to be advertised within Key-Value Topology Information Elements (KV-TIEs). There are no restrictions placed on the type of data that is contained in KV-TIEs nor what the data is used for.
For example, it might be beneficial to advertise overlay protocol state from leaf nodes to the Top-of-Fabric (ToF) nodes. This would make it possible to view critical state of a fabric-wide service from a single ToF node rather than retrieving and reconciling the same state from multiple leaf nodes.
Key Structure
This section describes the generic Key structure and semantics, Figure 1 further illustrates these components.
Generic Key-Value Structure

 0                   1                   2                   3
 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|   Key-Type    |                Key Identifier                 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                      Values (variable)                        |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

where:
- Key-Type:
A 1-byte value that identifies the Key-Type. It MUST be a reserved value from the RIFT Key-Type Registry that is defined later in this document.
The range of valid values is 1 - 255 (2^8-1).
0 is an illegal value and MUST NOT be allocated to or used by any implementation. It MUST be ignored on receipt.
Key Identifier:
A 3-byte value that identifies the specific key and describes the structure of the contained values.
The range of valid values is 1 - 16777215 (2^24-1).
0 is an illegal value and MUST NOT be allocated to or used by any implementation. It MUST be ignored on receipt.
Values:
A variable length value that contains data associated with the Key Identifier. It SHOULD contain 1 or more elements. Whether the collection of elements allows duplicates and/or is ordered is governed by the particular Key Identifier's specification.
Experimental Key-Type
This section reserves a value in the RIFT Key-Type Registry to indicate an Experimental Key-Type.
As shown in Figure 2, the Key-Type will be used to identify the Key-Type as Experimental. The Key Identifier will be used to identify the specific key and describe the structure of the contained values.
Experimental Key-Type

 0                   1                   2                   3
 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|       1       |          Experimental Key Identifier          |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                 Experimental Values (variable)                |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Well-Known Key-Type
This section reserves a value in the RIFT Key-Type Registry to indicate Well-Known Key-Types that all implementations SHOULD support.
As shown in Figure 3, the Key-Type will be used to identify the Key-Type as Well-Known. The Key Identifier will be used to identify the specific key and describe the structure of the contained values.
Well-Known Key-Type

 0                   1                   2                   3
 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|       2       |        Well-Known Key Identifier              |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                 Well-Known Values (variable)                  |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

OUI Key-Type
This section reserves a value in the RIFT Key-Type Registry to indicate an OUI (vendor-specific) Key-Type that any implementation MAY support.
As shown in Figure 4, the Key-Type will be used to identify the Key-Type as OUI. The Key Identifier MUST use the implementing organization's reserved OUI space to indicate the key and value structure.
OUI Key-Type

 0                   1                   2                   3
 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|       3       |              OUI Key Identifier               |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|               Vendor Specific Values (variable)               |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Operational Considerations
While no restrictions are placed on Key-Value data or what it is used for, it is RECOMMENDED that a serialized Thrift model be used for simpler interoperability. [RIFT-AUTO-EVPN] is an example of this type of implementation.
Key-Value elements SHOULD NOT be used to carry topology information used by RIFT itself to perform distributed computations.
In cases where KV-TIEs are flooded from north to south, policies SHOULD be implemented in order to avoid network-wide flooding.
For networks with more than one ToF node, it is RECOMMENDED that those ToF nodes contain identical KV-TIE information when being distributed from north to south. RIFT requires that only one KV-TIE is selected when identical keys are received from multiple northbound neighbors. If this is not considered then the tie-breaking rules may cause a node to select a suboptimal KV-TIE. Consider a case where failure conditions cause the ToF nodes to become split-brained. While the Key-Type and Key Identifier will be identical, the value(s) contained within may differ. The node(s) receiving these differing KV-TIEs will select the one from the ToF node with the highest System ID, potentially leading to unintended effects.
IANA Considerations
Per [RFC8126], IANA is requested to create two new registries under the top-level "RIFT" category:
- RIFT Key-Types
- RIFT Well-Known Key-Types
The following sections detail each registry's individual requirements and suggested values.
Experts reviewing requests for new values to either registry MUST consider the items in the Expert Review Guidance section.
RIFT Key-Types
This section requests that IANA create and help govern the following registry:
- Registry Name:
RIFT Key-Types
Registration Procedures:
Expert Review
Description:
Key-Type registry for the RIFT protocol.
Reference:
This document.
RIFT Key-Types Requested Entries
This section requests that IANA register the following suggested values to the "RIFT Key-Types" registry.
Value | Key-Type | Description | Status/Reference
0 | Illegal | Not allowed. | This document
1 | Experimental | Indicates that the Key-Type is Experimental. | This document.
2 | Well-Known | Indicates that the Key-Type is Well-Known. | This document.
3 | OUI | Indicates that the Key-Type is OUI (vendor specific). | This document.
RIFT Well-Known Key-Types
This section requests that IANA create and help govern the following registry:
- Registry Name:
RIFT Well-Known Key-Types
Registration Procedures:
Expert Review
Description:
Well-Known Key-Types registry for the RIFT protocol.
Reference:
This document.
RIFT Well-Known Key-Types Requested Entries
This section requests that IANA register the following suggested values to the "RIFT Well-Known Key-Types" Registry.
Value | Key-Identifier | Description | Status/Reference
0 | Illegal | Not allowed. | This document.
1 | MAC/IP Binding | To be defined. | To be defined.
2 | FAM Security Roll-Over Key | To be defined. | To be defined.
Expert Review Guidance
Experts reviewing requests for values from the "RIFT Key-Types" registry or the "RIFT Well-Known Key-Types" registry are responsible for the following:
1. Determining the existence of a specification that clearly defines the purpose supporting the request and MUST contain all required fields for given registry.
The document MUST also be permenent and publically available.
2. Ensuring that any requests are made available to the RIFT working group for review should the work originate from outside of the RIFT Working Group.
3. Ensuring that any work produce outside of the IETF does not conflict with any work that is already published or actively pursuing being published.
Security Considerations
This document introduces no new security concerns to RIFT or other specifications referenced in this document given that the Key-Value TIEs are already extensively secured by the RIFT protocol specification itself.
Acknowledgements
To be provided.
Normative References
[RFC2119]

Key words for use in RFCs to Indicate Requirement Levels
DOI 10.17487/RFC2119
RFC 2119
BCP 14
S. Bradner
March 1997
[RFC8126]

Guidelines for Writing an IANA Considerations Section in RFCs
M. Cotton
B. Leiba
T. Narten
June 2017
[RIFT]

RIFT: Routing in Fat Trees
Work in Progress draft-ietf-rift-rift-15
Tony Przygienda
Alankar Sharma
Pascal Thubert
Bruno Rijsman
Dmitry Afanasiev
July 2021
Informative References
[RIFT-AUTO-EVPN]

RIFT Auto-EVPN
Work in Progress, draft-ietf-rift-auto-evpn-03
Jordan Head
Tony Przygienda
Wen Lin
June 2022
[THRIFT]

Thrift Language Implementation and Documentation
Apache Software Foundation
[RFC8174]