Understanding Power Management On Ex Series Switches; Power Priority Of Line Cards - Juniper JUNOS OS 10.4 - FOR EX REV 1 Manual

Complete Software Guide for Junos

Understanding Power Management on EX Series Switches

Power Priority of Line Cards

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OS for EX Series Ethernet Switches, Release 10.4
The power management feature for Juniper Networks EX8200 Ethernet Switches helps
ensure that normal operation of the system is not disrupted because of insufficient power
to the switch. It does so by employing a power budget policy.
Power management does the following in its power budget policy:
Budgets power for each switch component that requires power. The amount that
power management budgets for each component is the maximum power that
component might consume. For example, for the fan tray, power management budgets
the amount of power required to run the fans at their maximum speed setting.
Reserves a set amount of power for power supply redundancy. In its default
configuration, power management manages the switch for N+1 power redundancy,
which ensures uninterrupted system operation if one power supply fails. For example,
if a switch has four online 3000 W power supplies, power management reserves 3000
W in its power budget policy for redundancy. It allocates the remaining 9000 W to
normal operating power.
Specifies the rules under which components receive power. These rules are designed
to ensure the least disruption to switch operation under conditions of insufficient power.
For example, power management provides power to core system components, such
as the Routing Engine, before it provides power to line cards.
You can configure certain aspects of power management's budget policy, specifically:
The power priority of individual line cards. By assigning different power priorities to the
line cards, you can determine which line cards are more likely to receive power in the
event of insufficient power.
The power redundancy configuration. The default power redundancy configuration is
N+1; you can optionally configure N+N. For example, if you have deployed two
independent AC power feeds to the switch, configure N+N redundancy. When you
configure power management for N+N redundancy, it reserves the appropriate amount
of power in its power budget and reports insufficient power conditions accordingly.
These configurable items are discussed further in:
Power Priority of Line Cards on page 1178
Power Supply Redundancy on page 1180
Power management powers line cards on or off based on the power priority of the slots
they occupy:
When a switch powers on, power management provides power to the line cards in the
order of their slot priority, with line cards in high priority slots receiving power first. Thus
if available power (including redundant power) is exhausted before all line cards receive
power, higher priority cards are powered on while lower priority cards remain powered
off.
Copyright © 2010, Juniper Networks, Inc.