Power Supply Features
The Cisco ASR 902 Router supports AC and DC power supplies. For more information about installing the
Cisco ASR 902 Router power supplies, see the
section. The power sections provide
more information about the power supply:
Redundancy
The Cisco ASR 902 Router chassis includes a slot for 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 902 Router supports current sharing
between the power supplies.
A redundant power supply on the Cisco ASR 902 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
power feeds are required.
Caution
Dying Gasp
The Cisco ASR 902 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.
Continued DC power supply operation may vary for voltages other than +24/
–
48V.
Note
Dying Gasp is not supported on the ASR 900 RSP3 module with the 1200 W 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 902 Router, see
DC Power Specifications
The Cisco ASR 902 Router uses a +24/-48 DC voltage power supply (with DC voltage tolerance from -19 to
-72 VDC).
Cisco ASR 902 and ASR 902U Aggregation Services Router Hardware Installation Guide
4
Overview
Power Supply Features