I was always under the impression that CEF was a "hardware" switching technology. Yet, I keep hearing and seeing through different commands "show ip cef" and "show mls .." that there is "hardware" cef switching and "software" cef switching. Can someone explain the difference without quoting a Cisco document as I have already read these.
to be noted that the process of creating the CEF table and to update it when something changes is performed in software in all cases by the routing processor. The CEF table may be sent to modules that have a local complete copy of the CEF table this is called distributed CEF and provides the greatest performance and scalability.
The C6500 is interesting because it can mix centralized CEF modules with distributed CEF modules (those mounting a DCEF daughter card)
So to verify my understanding, the lower end routers that use cef still use the features of cef (fib and adj table), but it's done using ios instead of special hardware components which I'm assuming are asics or specialized processors. However, even though the switching is done in software, it is still superior in performance to "process switching" because you're not having to interrupt the processor every time to switch a packet.
4- Application Specific Intergrated Ciruits (CEF in ASICs)
Process Switching : By which the packet sent to the processor to perform Switching.
Fast Switching: Is a Switching mechanism that Creates Table On demand.
CEF Switching: is a Switching mechanism that Copies and Mirrors all Routing information base into the CEF Forward Information base as soon as the router starts up and its therfore a topology driven Switching mechanism..
ASIC: The Hardware Is correctly programmed to forward the packet (Switch the packet).
I understand that CEF switching is better. I just don’t understand which will be used when. I know of some processor-switches packets such as to the device and NAT, but what about regular data traffic. Will it use software CEF or hardware CEF?
We are pleased to announce availability of Beta software for 16.6.3. 16.6.3 will be the second rebuild on the 16.6 release train targeted towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are looking for early feedback from custome...