". . . what is the most important specification in the switch and router shewed i look to it ? "
That's very much "in the eyes of the beholder". I.e., depends on your network requirements. That said, minimally, you often want to insure that switches or routers can handle the intended traffic load, yet not purchase capacity that will never be used. Next, insure the equipment offers the features your network needs to function as desired. For instance, if your network will support VoIP, you'll probably want some kind of QoS features to insure VoIP packets can be provided the priority treatment they need.
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...