In this video, Bill Ferguson dissects Class A addresses, where the first bit in the IP address is set to 0. Examine the effect of this setting on the rest of the IP addressing structure.
- [Instructor] To create networks that would support…millions of hosts, the designers of the internet…and of IP addressing devised the Class A Address.…In the Class A Address, the first bit is always set…to zero, that means that if you were to total the values…of all of the rest of the bits, the highest that you could…possibly get in that first octet with the first bit set…to zero would be 127, but they said 127 is not allowed…either, as part of the standard, the designers set aside…127 dot anything for their own network diagnostic purposes.…
So what does that do for us?…Well as far as the number of networks, two to the power…of seven for the seven bits in the first octet would give…us 128 networks, however, we're not going to use the zero…because that means that nothing came on at any time.…And we're not going to use the 127 because that's part…of the standard that is network diagnostic.…So that leaves 126 networks.…
Now, it's only a Class A Address though, if the subnet…mask is 255.0.0.0 which could also be expressed by /8.…
Discover how IP addresses are constructed and how to understand them better by relating them to a picture rather than converting binary numbers or memorizing charts. Learn the benefits that subnetting in your head provides in every aspect of IT networking, including routing protocols, access control lists, and network address translation. Then walk through Bill's four-step method, which leverages the rules that were used to create the original classful IP addressing schemes. Using this method, students can learn to "see" the IP addresses for each subnet. Watch the technique in action, and then practice what you've learned using the audio guides in chapter five, which provide auditory cues as you subnet in your head.
- The benefits of subnetting
- Class A, B, and C IP addressing
- The four-step subnetting method
- Troubleshooting IP topologies and IP host address ranges
- Audio cues for the four-step method