Cisco ASR 9000 Boot Loop After Upgrade: IOS XR Recovery

A Cisco ASR 9000 that boots into a loop after an IOS XR upgrade is one of the more alarming failure modes in a service provider network — line cards come up, crash, and reload endlessly while the router never reaches a stable forwarding state. Cisco's IOS XR system setup troubleshooting guide identifies a software synchronization problem after upgrades performed with customized GISO images containing updated SMUs on top of a base ISO. This article translates that official procedure into a practical recovery run book.

Why Line Cards Boot-Loop After an Upgrade

When a router is upgraded using a customized GISO image that layers updated SMUs over a base ISO image, the software set on the route processor and the software set expected by the line cards can fall out of sync. The line cards then repeatedly fail bring-up and reload. The fix is not to re-copy the image — it is to force a software synchronization so every node reloads from the network boot media with the correct software set.

Recovery Procedure: Software Synchronization

Execute the hw-module location bootmedia network reload command to enforce software synchronization on the affected nodes. This reloads the node using the network boot media, which pulls the active software set and brings the card back in sync:

Router# hw-module location all bootmedia network reload
Router# hw-module location 0/0/CPU0 bootmedia network reload

The first form targets every node; the second form is for a single line card or route processor specified in rack/slot/module notation. Run it from admin or EXEC mode according to your IOS XR release, then let the node complete the reload cycle before checking state.

Make FPD Auto-Upgrade Work for You

Cisco explicitly recommends enabling the FPD auto-upgrade feature for a successful software synchronization. If FPD images on the line cards are older than what the new software expects, the card can fail bring-up again after the sync:

Router(config)# hw-module location 0/0/CPU0 fpd auto-upgrade
Router# show fpd package
Router# show hw-module fpd location 0/0/CPU0

Confirm the FPD package versions with show fpd package before and after the reload so you can prove the upgrade completed. FPD issues have their own dedicated recovery path — see our ASR 9901 SW_INACTIVE FPD firmware reflash guide for that scenario.

Verifying the Router Recovered

After the sync completes, verify that every node is stable and running the committed software set:

Router# show platform
Router# show install active summary
Router# show install committed
Router# show redundancy

All line cards should show IOS XR RUN or a steady OK state in show platform, and the active software set should match the committed set. If cards still flap, escalate with show tech-support collected from the affected location before contacting the TAC. Related show-command fundamentals for ASR 9000 IOS XR are covered in our ASR 9000 show command guide.

原文链接：https://www.cisco.com/c/en/us/td/docs/routers/asr9000/software/26xx/system-setup/configuration/guide/b-system-setup-cg-asr9000-26xx/m-troubleshooting.html