A YANG model for Power Management

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Table of Contents

1. Introduction

Network sustainability is a key issue facing the industry. Networks consume significant amounts of power at a time when the cost of power is rising and sensitivity about sustainability is very high. As an industry, we need to find ways to optimize the power efficiency of our networks both at a micro and macro level. We have observed that traffic levels fluctuate and when traffic ebbs there is much more capacity than is needed. Powering off portions of network elements could save a significant amount of power, but to scale and be practical, this must be automated.¶

The natural mechanism for enabling automation would be a Yet Another Next Generation (YANG) interface, so this document proposes a YANG model for power management.¶

[RFC8348] already provides a model for server hardware management, but does not naturally extend to routers and other network elements. That gap is currently being addressed by [I-D.wzwb-opsawg-network-inventory-management] and [I-D.ietf-ccamp-network-inventory-yang]. This document extends the work presented there to include power management.¶

This initial draft only provides a tree representation. When there is rough consensus on the tree represetnation, the details of the model will be fleshed out.¶

2. Power Management Elements

The models mentioned above already model a router or network element as a set of components. The details of those components are left to the specific implementation and can be at any level of specificity. Thanks to this flexibility, it is necessary and sufficient that we characterize power management relative to components.¶

The elements defined below allow management entities to understand how much power each component is using and whether the component can be placed into a ‘power-save’ mode where it would consume less power. Another element allows the management plane to put the component into power-save mode.¶

3. Functional Dependencies

Most inventory models have a hierarchy of components. This hierarchy reflects the physical structure of the system (e.g., a line card can physically contain a port).¶

With regard to physical containment, components maintain a one-to-many relationship. That is, Component A can contain many other components, including Component B. However, component B can be contain by only one component (i.e., Component A.)¶

However, legacy inventory models do not reflect functional dependencies. Specifically, they do not indicate which components obtain services from, and therefore depend, components other than their container. Because funtional dependencies are relavant to power management, they are included in the proposed model.¶

With regard to functional dependencies, components maintain a many-to-many relationship. That is, a component can reuire on many components and be required by many other components.¶

Functional dependencies may be updated dynamically.¶

4. Tree Representation

 +--ro component* [uuid]
    +--ro uuid                          yang:uuid
    +--ro used-power?                   uint32
    +--ro power-save-capable?           boolean
    +--rw power-save?                   boolean
    +--ro required-components*          -> ../uuid
    +--ro dependent-components*         -> ../uuid

5. Security Considerations

YANG provides information about and configuration capabilities to the network management plane. Other mechanisms already exist that help secure these interactions. This document extends the scope of what can be controlled by the management plane, but creates no new access paths.¶

6. IANA Considerations

This document makes no requests for IANA.¶

Authors' Addresses