Table 51: Power Reserved For The Chassis - Juniper EX8208 Complete Hardware Manual

Complete Hardware Guide for EX8208 Ethernet Switches
112
To calculate the number of power supplies required for your switch configuration:
Determine the power requirement of the base chassis (that is, the combined power
1.
requirements of the fan tray, SRE module or modules, and the SF module) by
consulting Table 51 on page 112.
The watt values shown in Table 51 on page 112 are the amount of power reserved by
power management for the chassis in its power budget. It uses these values when
calculating used and available power and when determining whether sufficient power
exists to meet N, N+1, or N+N requirements.
Starting with Junos OS Release 10.2, when power management is configured for N+N
power redundancy, it reserves less power for the chassis so that more power is
available for line cards.

Table 51: Power Reserved for the Chassis

N+1 Configuration
N+N Configuration
NOTE: The amount of power that power management reserves for the
chassis is a set value that does not vary depending on chassis components
installed. The reserved power is the same for base and redundant
configurations and for switches that do not have all base chassis
components installed.
To the power reserved for the chassis, add the power requirements of the line cards.
2.
For line card power requirements, refer to "Power Requirements for EX8208 Switch
Components" on page 105.
For example, for a switch fully loaded with 8-port SFP+ line cards and using N+1 power
redundancy, the total power requirement:
= reserved chassis power + 8 (8–port SFP + line cards)
= 1600 W + 8 (450) W
= 1600 W + 3600 W
= 5200 W
For a switch fully loaded with 8-port SFP+ line cards, using N+N power redundancy,
and running Junos OS Release 10.2, the total power requirement:
= reserved chassis power + 8 (8–port SFP + line cards)
= 1200 W + 8 (450) W
= 1200 W + 3600 W
Junos OS Release 10.1 or
Earlier
1600 W
1600 W
Copyright © 2010, Juniper Networks, Inc.
Junos OS Release 10.2 or
Later
1600 W
1200 W