if one side isl and the other is dot 1q the link will work you just will get native vlan miss matches on the dot1q side and also may course baby giant frames.
A switch can use a mixture of 802.1q and ISL encapsulations on trunk links but a trunk link between 2 switches must be the same encapsulation as ISL and 802.1q use very different methods when they add a vlan tag ie.
802.1q inserts a tag into the existing frame
ISL actually encapsulates the frame with a new header
so the 2 switches must agree on the encapsulation being used per trunk link otherwise they will be looking for the vlan information in the wrong place.
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...