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Why is subnetting so important?

Morty3

Subnetting is a rly important part of ICND1. But my question is, why is it this important? I mean, you are not likely to need it becouse of NATing! Also in IPv6 it does not even exist since it is not at all needed.

Morty

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Comments

EdTheLad

Subnetting does exist in IPv6, 16 bits are assigned for subnetting.Subnetting is used everywhere, ip is classless which means different length masks are used everywhere.If you dont understand subnetting you wont understand wildcard masking,summarization,route filtering etc..
If you stick around here and continue to study i'm sure you will look back on this post and laugh.

Morty3

Hehe, I've studied so much that I can do subnetting in my head by now. I know that IP addresses on the internet are classless by now, you just pick a mask that suits you. But, when you are doing your own network you will not need it, since you will only get 1, max 2 addresses anyhow. Thats why I dont see why it is so important.

Wildcardmasking and summerization is of course very valuable, but I cant see why it is so important to do clean subnetting as much as we, who are going for ICND1, need to do.

EdTheLad

If you only want to manage an internal network natting to a couple of public addresses thats fine,i dont thing you'll make to much cash taking that path.
Subnetting is easy points in the exam, if you think there is too much subnetting in ICND1 maybe you should have taken the one exam route.

Subnetting is a hugh part of routing, it gets you thinking about the binary and how to manipulte route which leads into all other areas, if you just brush over this section without an understanding you will be screwed in most other routing sections.

Take the one exam route otherwise get back to you're subnetting

miller811

Morty3 wrote: »

Hehe, I've studied so much that I can do subnetting in my head by now. I know that IP addresses on the internet are classless by now, you just pick a mask that suits you. But, when you are doing your own network you will not need it, since you will only get 1, max 2 addresses anyhow. Thats why I dont see why it is so important.

Wildcardmasking and summerization is of course very valuable, but I cant see why it is so important to do clean subnetting as much as we, who are going for ICND1, need to do.

Learn it now, or fail in the future..... all of the material builds as you progress on the Cisco track.

Miikey87

If you can subnet you can VLSM which is fun and efficient as well.

Lots of it in ICND1 but you see it in ICND2 as well, and as all others have stated, it is everywhere through wildcards, route sumarisation, vlsm etc. Good fun

shednik

Just wait until you work for a company with over 125,000 users and tell me you don't need to use subnetting to make your network run efficiently...then I want you to prove it that you don't need to use it.

You will see over time the importance once you begin to work with networks.

Morty3

Thanks guys! Means a lot to me to get some perspective on this.

I do not want to go with the 1 exam, since I am so nervous when it comes to tests :P

luke_bibby

Imagine an ARP request broadcasted to 65000 hosts! Yikes

Jim Hamilton

I went the 1 exam route when i got the CCNA, and i prayed for as many subnetting questions as possible, they're freebies man. But the roots of it are important. Just ask someone who programs assembler. Bitmasking is king. It is the essence of efficiency.

bulletproof baba

Subnetting is important for several reasons.

Subnetting helps to reduce the number of routes needed in a routing table.

This was extremely important to the Internet. In the early days of the Internet, companies were directly assigned IP address ranges by the Internet Assigned Numbers Authority (IANA). As the Internet grew, each of the uniquely assigned ranges had to be included in the Internet routing table, and this quickly resulted in huge routing tables. At this point, IANA decided that instead of issuing IP address ranges directly to companies, it would set up regional authorities that would distribute IP addresses. These regional authorities are ARIN (North America), RIPE (Europe), LACNIC (Latin America), APNIC (Asia), and AFRINIC (Africa).
Each of these agencies is assigned a large block of addresses by IANA; the agency then subnets these blocks and assigns them to the various Internet service providers (ISPs). The ISPs subnet their addresses even further and assign them to their customers. Now when packets are routed through the Internet, the main Internet routers need to know only which region to get it to instead of every company or network connected to the Internet. The region can then get it to the ISP and the ISP knows where it is supposed to go from there.

Subnetting allows you to make efficient use of your address space.

If you only have a network of two hosts, such as a wide area network (WAN) link, why would you waste an IP address range of 254 addresses?

Subnetting can also aid with troubleshooting an issue.

If you have one large flat network, when problems arise it is often difficult to physically track down where the problem is coming from. If you subnet your network intelligently, you can more easily determine where, in the physical network, problems exist.

From a security perspective, subnetting can also help you isolate networks that may be high risk or process sensitive or critical data.

With subnetting, you can isolate wireless networks, research and development, finance and human resource networks, internet facing networks, and so on. By utilizing firewalls and intrusion detection systems, you can more easily regulate who has access in and out of a particular network.

Hope this makes it little clearer

Morty3

Great post

bulletproof baba

Thanks Morty3, hope that helps you !