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All routed traffic is being black holed

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Information

 
TitleAll routed traffic is being black holed
Symptoms
  • Traffic that is supposed to layer 3 route is being dropped
  • L2 traffic forwarding is working fine
  • L3 traffic is using VRRP for default gateway 
  • No congestion seen
Environment
  • Summit X460
  • Summit X670
  • EXOS 15.2.3.2
  • Summit Stack
  • FDB Learning
Cause
  • Table mismatch in hardware and software for the vrrp mac address
  • SW port shows mac address learned on correct port, while hardware shows the wrong port causing traffic to be silently dropped/blackholed
  • High count of mac moves on the network
  • Devices with high count of mac moves are all the same device and using the same mac address which is not properly following 802.3 standards
Resolution
disable learning vlan <vlan name>

Disable learning on the vlan causes the traffic from these devices to flood but puts less stress on the switch to program and reprogram FDB entries constantly.  
 
Additional notes
  • In this example, high count of mac moves, adds and deletes were being caused by third party HDMI passthrough devices.  
    • The devices do not appear to be following typical ethernet standards as all the devices spread through out the network have the same mac address.  
    • This abnormal behavior causes the switch to become confused and program entries wrong due to the multiple mac moves, adds and deletes required when a packet ingresses a switch port.
  • Please call Extreme TAC for high level debug commands to view software and hardware learned entries

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