I have read many data sheets on the Nexus 7000 series and it's cards purporting to be capable of OIR (Online Insertion and Removal).

However I have never needed to replace/reseat/add any Nexus line cards since I walked into this Nexus deployment two years ago. (Several power supplies and a fan tray, but no line cards.)

Is replacing (or adding) a line card truly impact-free on the other line cards/traffic that is currently in production?

To test, I have scheduled a downtime for testing to involve replacing one of the line cards and one of the supervisors.

However I was wondering if any of you could give me a heads up on what to expect.

4 Answers 4


"Yes, it's completely impact-free.*

*Your experience may vary."

That's the impression I get from Cisco and the Nexus platform in general. As a general rule, I always try to secure a maintenance window for work on critical infrastructure as a CYA measure. Even if it works flawlessly 99% of the time, there's still that 1% that it won't, and "But Cisco told us it would be fine" does little to placate angry customers.

  • 2
    This is true for pretty much all vendors, although I might lower the success rate to 95%.
    – LapTop006
    May 14, 2013 at 22:26

On paper, yes. In reality, don't bet on it. As Mr. Stretch brings up... are you willing to bet your job on it not interrupting the CEO's video conference?

(In my experience, Cisco OIR is always an incalculable gamble. Sometimes it works perfectly. Others is creates noise on the bus that crashes the entire router. Or my fav... corrupts one of the buses and half the linecards disappear/reboot.)


In my experience the 7K OIR function is 'hitless' with respect to the other linecards. However, keep in mind that in a configuration where M1 and F1 cards are mixed, the M1's handle all of the L3 functions, so removing the M1 will impact traffic on the others, hence the recommendation to have two in the system in such a config. Also, if the system is carved into VDCs, you will want to understand any dependencies each VDC has on the card.


Also, on shutdown or online of a card the N7k has to rewrite some or all other forwarding engines if this card contained part of a channel. this may cause a short traffic interruption.

but if the card is blank you should be fine. i would shutdown the card via cli before i do the OIR.

there are no such issues like bus-stall we had with the cat6k and we never had any problems.

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