Redundancy - Cisco ASR 903 Hardware Installation Manual

Cisco ASR 903 Router Overview
The power sections provide more information about the power supply:

Redundancy

The Cisco ASR 903 Router chassis includes a slot for an optional redundant power supply. The redundant
power supply option provides a second power supply to ensure that power to the chassis continues uninterrupted
if one power supply fails or input power on one line fails. Redundancy is supported either with identical power
supplies or a combination of AC and DC power supply. The Cisco ASR 903 Router supports current sharing
between the power supplies.
A redundant power supply on the Cisco ASR 903 Router is recommended. Each power supply should be
connected to separate independent power sources to ensure that the router maintains power in the event of a
power interruption caused by an electrical failure, a wiring fault, or a tripped circuit breaker.
To comply with IEC 61850-3 (voltage interruptions), redundant power supplies with separately derived
Caution
power feeds are required.
Dying Gasp
The Cisco ASR 903 Router DC power supply supports the Dying Gasp feature, which allows the router to
provide an input power loss notification to the RSP so that the RSP can send appropriate SNMP traps or OAM
messages and update log files on the router. With the DC power supply, the router supports a minimum input
power loss detection time of 2 milliseconds (DC) and continued operation of at least 6 milliseconds (DC)
after the notification.
Note Continued DC power supply operation may vary for voltages other than +24/-48V.
Dying Gasp is not supported on the ASR 900 RSP3 module for 1200W DC power supply.
Note
Status LEDs
LEDs are also provided on each power supply to indicate the status of the input power and the health of the
power supply. For more information about the LEDs on the Cisco ASR 903 Router, see Troubleshooting.
DC Power Specifications
The power supply is field replaceable, hot-swappable, and operates separately from the fan tray. The power
supply contains a front panel with mounting screws, a handle for insertion and removal, and two status LEDs.
No ON/OFF switch is provided.
The DC PSU models supported on the router are:
• A900-PWR550-D—Provides 550 W output power for system 12 V power. Uses a euro-style three-position
terminal block connector.
Cisco ASR 903 Aggregation Services Router Hardware Installation Guide
Power Supply Features
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