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Cisco Bug: CSCsz43080 - FIB not updated during SSO when SVI goes down

Last Modified

Jan 24, 2017

Products (1)

  • Cisco IOS

Known Affected Releases


Description (partial)


A cisco catalyst 4000 blackholes traffic during SSO recovery.


This issue is limited to scenarios where you have a vlan that is only allowed on a trunk which is on the supervisor which used to be active and is now being removed out of the chassis or suffers a hardware failure. 
If a route exists in the routing table and cef table before SSO starts which points out of this vlan interface which will go down during SSO due to only being allowed on the trunk port which is now gone, this vlan interface will stay in the CEF table even after the router declares the vlan interface to be down. This means that during the time in between SSO starting and the routing protocols reconverging, traffic will be blackholed.
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