[c-nsp] Clearing CEF entry (routing loop)

Ihsan Junaidi Ibrahim ihsan at synthexp.net
Thu Oct 27 00:39:56 EDT 2005


Hi all,

A routing loop has occurred in my network. I have 2 routers, R1 and R2 in  
which R2 is connected directly to R1 and R1 to our core network. Checking  
my routing table in both routers, the prefix is being forwarded to transit  
provider T1 however the CEF entry is pointing to another router, R3  
connected to another transit provider T2. My CEF entry at R1 is pointing  
to R2 as the next hop however at R2, the next hop entry is pointing to R1  
because R3 is accessible only via R1. So the packets are stuck in a  
perpetual loop.

I did try variations of clear ip cef commands such as
"clear ip cef xxx.xxx.xxx.xxx/18 prefix-statistics"
"clear ip cef xxx.xxx.xxx.xxx 255.255.192.0 prefix-statistics"

but still no avail. The CEF entry for that particular route still points  
to R3.

-- 
Thank you for your time,
Ihsan Junaidi Ibrahim


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