Subnet mask in the network statement just allows you to identify which interfaces will participate within EIGRP.So, yes, it is good practice to include this to give you better control of which interfaces are in your EIGRP process. If no-auto summary is enabled with in your EIGRP process you'll see subnets within your classful network statements rather than only seeing the classful (e.g. 10.0.0.0/8) network.
That makes sense it terms of not summarizing the subnets into classful statements. I'm not clear about how the subnet mask identifies the interface though. Fortunately, I have the latest BCSN training book so I will just have to review this.
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...