CEF Configuration

[reetesh]

 Can some help me out understand of disabling CEF on a particular interface?

I tried the lab on GNS3. As depicted in the screenshot I disabled cef on both the interfaces f0/0 and f0/1 of R2

no ip route-cache cef

The show ip int f0/0 | include CEF shows that CEF is disabled on interface f0/0 and similarly for interface f0/1

But the debug output on R2 shows the ICMP packet from R1 to R3 interface (f0/0) is routed via FIB on R2.

If CEF is disabled on both the interfaces of R2 how can the packet be routed via FIB. 

The FIB and the adjacency tables are used by CEF. 

Can someone explain me where I'm wrong? Thank you

[MHM Cisco World]

I will check this lab today, I will update you 

[reetesh]

Thank you so much.
I've gone through loads of explanations on CEF but there seems to be a
missing piece in the puzzle. When i disable CEF on an interface with the
command *no ip route-cache cef. *The packet
must be process switched and not via FIB.

[Martin L]

real image/real device or GNS3? what IOS version / model ? can u disable CEF in GNS3 ?  don't have access to my gns3 gear now; will check later

Regards, ML
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