ASR9000 Order of Linecards Power Down in Case of Insufficient Power

Introduction

This document describes how in an Aggregation Services Router 9000 (ASR9K) router when the power level drops to an insufficient level, linecards (LCs) start to power down.

Contributed by Sam Milstead, Cisco TAC Engineer.

Problem

Prior to 6.0.1 and 6.1.1 when the power levels dropped, cards were shut down randomly, and there was no way to influence which cards would be shut down first. This potentially caused outage or other problems for operators.

Solution

From 6.0.1 and 6.1.1 onwards, an admin configuration knob was introduced via CSCux09817 , that allowed to influence which cards would be shut down first in case of a power drop in an ASR9K system.

Here is a configuration example with LCs 0 and 1 shut down last and LC 4 shut down first.

power budget enforcement progressive
 priority 1
  location 0/0/CPU0
  location 0/1/CPU0
 !
 priority 2
  location 0/2/CPU0
 !
 priority 4
  location 0/3/CPU0
 !
 priority 19
  location 0/4/CPU0
 !
! 

Note: This only applies to LCs that are in the XR-RUN state. Any other state a LC is in, such as MBI-BOOTING, then it will not be affected by this configuration. So for instance, if LC 4 is booting and there is a power drop then LC 3 would be powered off first.