On Tue, 13 Oct 2009 08:14:59 -0400 Joe Abley <jabley@hopcount.ca> wrote:
While I may agree that teaching classful routing is stupid, the addressing part lets people start getting the concept of binary.
That's true of classless addressing, too. When students have problems with non-octet bit boundaries, that just means you start [...] You were suggesting that classful addressing is reasonable to teach because it's simpler. It's not simpler, and in a modern-day context it's just wrong.
I occasionally teach college level courses in networking, typically undergrads or grad students at DePaul University. I think I can offer some perspective from both the academic and operator viewpoint. No matter the class or the student, I always have to spend at least a week on IP addressing, even to students who should be coming in with already having had it, sometimes in multiple previous classes. Some know it fairly well, but with holes mostly due to lack of practical experience. I don't think I've seen anyone who would be considered expert enough to withstand the scrutiny of this crowd (though that probably goes for just about anyone really :-). No question about it, but something more than basic classful addressing for students who don't typically have to do it on a regular basis is not easy. Those who aren't afraid of math, can grasp numbering systems and binary arithmetic usually fare better. Some instructors are most certainly doing some harm. From what I can tell, classful addressing is always taught and if classless is taught, its practical reality and importance is not always stressed. In my most recent class this semester I made it abundantly clear to my students that classful addressing, while interesting and useful to know from a historic perspective, is obsolete and deprecated. A student who has another networking related class with another instructor came back saying their other instructor disagrees. :/ John