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Cisco Bug: CSCum58876 - RPF change is not updated correct or mfdm/ipfib crash if oifl > 40 svis

Last Modified

May 20, 2019

Products (1)

  • Cisco Nexus 9000 Series Switches

Known Affected Releases


Description (partial)

The QA-tested scalability limit for multicast on the Nexus 9500 is 40 outgoing interfaces
(OIFs) per multicast route (i.e. per (*,G) or (S,G) entry). When this is exceeded, unexpected
behavior has been observed, such as:

- RPF update failure - if the RPF path for a multicast source moves from a L3 interface to a
VLAN interface (SVI), this is not correctly updated in the FIB and in hardware programming. As
a result, streams from this source are punted to the supervisor due to RPF failure.

- The 'mfdm' service may crash on the supervisor, causing a HAP reset of one or both

- The 'ipfib' service may crash on any or all line cards and/or fabric modules,
causing a HAP reset of the affected module(s).

- MTS exhaustion may be observed.

The noted issues are known to occur when the OIF list (OIFL) exceeds 40 entries for one or more
multicast routes.

The device is not guaranteed to experience these crashes or programming failures once in this
state. However, once in this state, multicast churn (any actions that would require
reprogramming of multiple OIF lists in hardware) can cause the aforementioned issues to appear.
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