This confused me as well a while back and it was explained to me as follows: in the case of a 6500 switch with a SUP1A, CEF only applies to packets that are sent to the MSFC for processing. When MLS is enabled, this is the first packet of each flow. So, the first packet is sent to the MSFC and CEF-switched while the remaining packets in that slow are switched by the PFC via MLS.
When a SUP2 or SUP3, however, the PFC itself can use CEF, so there's no concept of MLS -- all IP packets (with the usual list of exceptions -- see the documentation) are CEF-switched by the PFC.
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...