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Why its important to learn about classful address nowadays?

its not something will be used and cisco know that, why bother give us old useless info in the exams

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level 1
CCNA R&S10 points · 6 months ago

To put it simply, part of knowing why things in modern networking are the way they are is knowing how things used to be done "back in the day" and why they came to suck. History is important because many high-level concepts in networking are improvements of previous technologies that are now obsolete.

Furthermore, one must consider RFC 1925's Rule 11: "Every old idea will be proposed again with a different name and a different presentation, regardless of whether it works." As you grow as a network engineer, you will start to notice patterns among different technologies. For example, you'll see MPLS and be able to notice that it's basically Frame Relay, but with different names, different headers, and more features. Or you'll see FlexVPN and realize that it's really just a simplified configuration of DMVPN with a few more features. Being able to recognize these patterns makes learning new technologies easier, but you'll never be able to gain this skill if you don't learn about the history of networking and how things used to be done.

level 1

You will come across legacy equipment and systems in the business world, guaranteed. You'll need to know about them in order to understand them.

level 1

To understand RIPv2 which needs

no auto-summary

or else it will act classful like RIPv1. This is still used in today's networking world.

CCNA is considered an entry level networking certification. You need to have a solid foundation which includes old useless info about bridges, hubs, CSMA-CD, etc. before you specialize in specific areas of networking.

level 1

How about when a wildcard mask isn't specified when setting up EIGRP and the router will automatically assume a subnet mask based on the class of the network IP address? In that case and many more, you will need to know classful networks. Just learn it.

level 1
Now with more Cisco!2 points · 6 months ago

its not something will be used

False.

why bother give us old useless info in the exams

Because it's not useless, just old. There are plenty of technologies that are considered "antiquated" that you will still have to deal with--some of these have been dropped from the CCNA, some are still present. It's the same reason you learn about CSMA/CD, rate or duplex negotiation, serial links, RIP, PPPoE and line passwords,

level 2
Just 'cause it ain't in my flair doesn't mean I don't have certs1 point · 6 months ago

its not something will be used

False.

If you're running RIP v1, you should be shot.

level 3
Now with more Cisco!1 point · 6 months ago

Sometimes you gotta choose between shooting the guy, or cashing his paycheck.

level 4
Just 'cause it ain't in my flair doesn't mean I don't have certs2 points · 6 months ago

I've literally never once had to have that battle, from mom and pop shops to Fortune 100 corporations. And if it came down to having to use RIP v1 or firing the customer, I would fire the customer instantaneously. If you're working with an organization like that, you're setting yourself up to join in their inevitable catastrophic failure.

level 1

I think its more to give you some history of networks,

level 1
Original Poster1 point · 6 months ago

thanks everyone for the insightful comments

level 1

Classful are still used in real network environment. You'd see them on summarization of routing tables. As suppose to sending 256X24 prefixes over to your BGP peer, you would send a summarize /16. This reduces CPU overhead and wasting resources like RAM/CACHE. You'd also see them on local OSPF clusters that advertise across areas.

level 1
Meow 🐈🐈Meow 🐱🐱 Meow Meow🍺🐈🐱Meow A+!1 point · 6 months ago

It is mostly there because it is a learning aid that helps you get IP addressing and its history, and also the fact that you can still encounter classful in the wild...all it would take is forgetting no auto on your RIP config and you are advertising classful.

level 2
Just 'cause it ain't in my flair doesn't mean I don't have certs1 point · 6 months ago

If only a manufacturer had the ability to make "no auto" come on automatically when a routing protocol is provisioned. I hear that they actually DID have that power, but could only do it once in the history of the Universe, and EIGRP got chosen instead.

level 3
Meow 🐈🐈Meow 🐱🐱 Meow Meow🍺🐈🐱Meow A+!1 point · 6 months ago

Ah yes I remember the great battle of "no auto" in the end there could only be one winner

level 4
Just 'cause it ain't in my flair doesn't mean I don't have certs1 point · 6 months ago

Like highlander

level 1
2x CCNA (R&S, Cyber Ops)1 point · 6 months ago

The same reason we learn about intel 8085 and simple automata machines. Welcome to computer science. You could also say "why do we need to learn binary conversion if all we gotta do is type commands". You can't write a poem if you don't know the language.

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