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Cisco Bug: CSCus52559 - MD floodLTL cause unnecessary flood frm M to learn MAC wrongly in F2e/F3

Last Modified

Mar 01, 2018

Products (1)

  • Cisco Nexus 7000 Series Switches

Known Affected Releases

6.2(12)S20 8.2(1)S9

Description (partial)

Whenever multicast traffic is flooded with MD flood LTL as the DI and if the chassis has any M modules that is powered up, the MD flood received in the M module is flooded back to the fabric.
This packet on reaching the F2e/F3 cards triggers egress MAC learn which sometimes could overwrite a existing MAC entry with a wrong destination port.

Conditions in which this issue could happen are:
1. Any M-series module should be up in the chassis


2. MD flood LTL will be used always if Private VLAN SVI part of OIF list for the mutlicast group 


3. Until an optimised multicast MD LTL is obtained for a mutlicast group, MD flood LTL will be used for a very brief period.
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