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Cisco Bug: CSCsz40600 - 1812 switch layer3-forwards packets which layer2 should process

Last Modified

Feb 02, 2017

Products (1)

  • Cisco 1800 Series Integrated Services Routers

Known Affected Releases

12.4(6)T

Description (partial)

Symptom:
  
  1812 switch port forward some packets by routing whereas the packets
  should be processed by Layer2 forwarding, when SVI(Switched Virtual
  Interface) has bridge-group.
  
  If two 1812 routers connect each other by switchport, and the MAC address
  entry for transit packet aging out, the transit packet may be duplicated
  for flooding and loop between two routers.
  
  This problem will be resolved by this enhancement request adding a feature
  of software MAC filtering.
  
 Condition:
  
   - Cisco1812 switchport(FastEthernet2 ~ FastEthernet9)
  
   - The MAC address entry for the transit packet does not exist in MAC
     address table due to MAC age out etc. But, the ARP entry exists in
     ARP cache table. Then, the transit packet is flooded to all related
     switch ports. As the result, the packet loop if two 1812 routers
     connect each other by switchport.
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  • Status
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