Asr 5000 System Administration Guide, Staros Release 21.1 - Cisco ASR 5000 Administration Manual

Understanding the ASR 5000 Boot Process
The following flowchart shows each step in the startup process. For additional information about system
configuration files, refer to the Understanding Configuration Files section.
Figure 3: ASR 5500 Process Flowchart
The following steps describe the system's boot process:
Step 1 When power is first applied to the chassis, or after a reboot, only the SMC slots (slots 8 and 9) receive power. Therefore,
the SMCs are the first cards to boot and their LEDs are the first to light up. After the system confirms that cards are
located in slots 8 and 9, power is quickly applied to the SPIOs in slots 24 and 25.
Step 2 During the startup process, each card performs a series of power-on self tests (POSTs) to ensure that the hardware is
operational.
Step 3
If the SMC in slot 8 successfully executes all POSTs, the card in slot 8 becomes the active SMC. The SMC in slot 9
becomes the standby card. If there is a problem with the SMC in slot 8, the card in slot 9 becomes the active SMC. Once
the active and standby order is determined, the SPIO cards in slots 24 and 25 are placed into active and standby mode,
as determined by the direct mapping of the active and standby SMCs.
Step 4 The active SMC begins loading the operating system software image designated in the boot stack. The boot stack entries
are contained in the boot.sys file that resides on the SMC CompactFlash. The standby SMC observes the active card
startup. If the file on the active card is loads normally, the standby SMC boots from the active card image. If the active

ASR 5000 System Administration Guide, StarOS Release 21.1

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System Operation and Configuration