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Cisco admins: Hold that IOS XR update while you get new software

Old components can freeze new NCS 6000 cards running old code

Update Eight Cisco NCS 6000 line cards need software upgrades, after Switchzilla learned they could be bricked by an IOS XR upgrade.

The operating system upgrade in question is IOS XR 5.2.x.

What Cisco found is that a number of line cards in the NC6 range with “updated 500 MHz ternary content-addressable memory (TCAM)” could either fail to boot, or move into the “IN-RESET” state unless they have a System Management Unit Software Maintenance Upgrade as well.

The symptom is pretty unmistakeable: if you install a new line card in a system running IOS XR 5.2.x, you'll get a Network Processor Unit (NPU) initialisation failure with a "No such device" error.

Its field notice explained that the cards were changed from 300 MHz TCAM to 500 MHz when a third-party component went end-of-life – and that impacted the initialisation sequence of the affected cards.

Once the customer's run the upgrade, IOS XR 5.2.x supports both 300 MHz and 500 MHz line cards. Routers running IOS XR 6.1.x aren't affected – so upgrading to that version means you don't have to install other upgrades.

The 500 MHz line cards are identified as V03, either by querying the IDProm (instruction Show 0/1-IDPROM), or on the label on the right side of the line card. ®

Update: A Cisco engineer has contacted us expanding on the detail of the issue.

"There is no firmware upgrade required, rather the SMU is required on 52x release to boot up new cards with 500 MHz TCAM. Later releases don’t need any upgrade or SMU. They have the software patch integrated. The older TCAM cards (340 MHz) will work with all available releases without any need of upgrading any component.

"In result, no card is ‘bricked’ by IOS XR upgrade. Rather new cards just need SMU to work on particular releases i.e. 52x."

We note that without the right software in place, the cards could fail to boot, so we're comfortable with the colloqiualism "bricked" in that particular instance – El Reg.

Update 2: There remained a point which the Cisco engineer – a long-time specialist in field service – wanted clarified, but we're happy to say it wasn't our error.

The original field notice described the issue as “BIOS/firmware upgrade required” – but that was an error on the part of someone at Cisco. The engineer advised that it will be revised to describe the issue as a software upgrade.

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