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Cisco Bug: CSCur12257 - L2FM OOO Static MAC issue after ISSU followed by peer-link flap

Last Modified

Oct 02, 2018

Products (8)

  • Cisco Nexus 7000 Series Switches
  • Cisco Nexus 7000 10-Slot Switch
  • Cisco Nexus 7000 4-Slot Switch
  • Cisco Nexus 7700 6-Slot Switch
  • Cisco Nexus 7700 18-Slot Switch
  • Cisco Nexus 7000 18-Slot Switch
  • Cisco Nexus 7000 9-Slot Switch
  • Cisco Nexus 7700 10-Slot Switch

Known Affected Releases

6.2(8a)

Description (partial)

Symptom:
HSRP VMAC for some vlans may not have G and R bit set. This will result in unicast flooding for the packets destined to HSRP vmac

Broken State
`show mac address-table`
Legend: 
      * - primary entry, G - Gateway MAC, (R) - Routed MAC, O - Overlay MAC
      age - seconds since last seen,+ - primary entry using vPC Peer-Link,
      (T) - True, (F) - False
   VLAN     MAC Address      Type      age     Secure NTFY Ports/SWID.SSID.LID
---------+-----------------+--------+---------+------+----+------------------
* 200      0000.0c9f.f0d0    static       -       F    F  Vlan200

Notice above G and R bit are missing. Also instead of a port it may mention vlan200 which means that it will be flooded to all the ports in that vlan


Correct State
`show mac address-table `
Legend: 
        * - primary entry, G - Gateway MAC, (R) - Routed MAC, O - Overlay MAC
        age - seconds since last seen,+ - primary entry using vPC Peer-Link,
        (T) - True, (F) - False
   VLAN     MAC Address      Type      age     Secure NTFY Ports/SWID.SSID.LID
---------+-----------------+--------+---------+------+----+------------------
G 200      0000.0c9f.f0d0    static       -       F    F  vPC Peer-Link(R)

Conditions:
Switchover (ISSU or even EPLD upgrade of supervisor which will cause sup failover) and then followed by flapping of peer-link (or bringing up peer-link)
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