Can't find what you need?


• Ask the Community
• Create a Case
Reset Search
 

 

Article

BGP session between CER and another vendor device not coming up.

« Go Back

Information

 
TitleBGP session between CER and another vendor device not coming up.
Symptoms
  •  BGP peering between CER and another vendor device
  • Layer 2 connection is going through EXOS stack switch
  • "show ip bgp summary” shows BGP state changes from Idle
  • Telnet to BGP neighbor with TCP port 179 doesnt get connected 
Environment
  • CER2024
  •  NI V6.3.0aT183
Cause
During investigation we have found that we are not receiving ARP reply on CER. 
CER was trying to initiate ARP but was not getting reply
Resolution
Enable below configuration on CER 

CER(config)#ip arp-cpu-protection

which will prevent persistent unknown unicast packets .
Additional notes
Enabling the above command will prevent persistent unknown unicast packets being sent to the CPU for MAC learning. Even rate--limiting the unknown unicast packet flow to the CPU may not be enough to reduce the high CPU utilization caused by these packets being processed by the CPU.This enhancement alleviates the situation by creating a temporary local DA MAC entry in CAM for each unknown unicast DA MAC address. The temporary CAM entry is used flood the unknown unicast packets in hardware without sending a copy to the CPU. This temporary entry ages out (as per the configured MAC age time) and will get re-created as long as MAC address remains unknown

Feedback

 

Was this article helpful?


   

Feedback

Please tell us how we can make this article more useful.

Characters Remaining: 255