topic CSCwn92248 - FTD FP2100 port-channel interfaces flap with LACP in Network Security

CSCwn92248 - FTD FP2100 port-channel interfaces flap with LACP

i.sboras@athexgroup.gr — Mon, 12 May 2025 07:59:16 GMT

Hello, is there any estimated time of resolution for this bug?

Re: CSCwn92248 - FTD FP2100 port-channel interfaces flap with LACP

Mark Elsen — Mon, 12 May 2025 09:44:59 GMT

- Note that your best approach to tackle this question is contacting Cisco's TAC ,

Re: CSCwn92248 - FTD FP2100 port-channel interfaces flap with LACP

Network Diver — Mon, 19 May 2025 06:20:32 GMT

We're having this on Firepower 1120 and 1150 devices, connected to N9K-C9348GC-FXP and also to N9K-C93180YC-FX, both running NXOS 10.2(4). But my posting was marked as SPAM. 😞

https://community.cisco.com/t5/network-security/firepower-1000-series-causes-lacp-link-flaps-with-nexus-9k/m-p/5291826#M1121044

Re: CSCwn92248 - FTD FP2100 port-channel interfaces flap with LACP

Network Diver — Thu, 22 May 2025 12:00:52 GMT

Link above to more in-depth details about this bug. I got response from Cisco TAC:

Can more than one port-channel member expire at once?

Yes. Due to the timer-management issue in the current FXOS/FTD code, when one member’s LACP state machine expires it can inadvertently drive the expired flag on all members of that same channel. When that happens, the switch will take down each affected link and, if enough members drop, the port-channel itself will clear and the FTD will trigger failover (since it’s monitoring link state).

Timing for a software correction

Engineering has prioritized CSCwn92248 for the upcoming 7.4.3 maintenance release (FXOS 2.15-series). At this time, QA is validating the fix and we expect it to become generally available in the July-timeframe (However, we do not have a definitive date yet). Once the maintenance train is officially posted, that build will include the corrected LACP-timer behavior so that members don’t all receive the expired indication simultaneously.