classful and classless addressing

[vrsf555]

Hi, I've been studying CCENT/CCNA ICND1 100-105 Official Cert Guide, Wendell Odom

We can find on page 350 the following statements:

 In this book, there are several references in the same way. Is there an error?.

Please, help.

Regards,

[Dan Lukes]

I see no error. IP and explicit mask is common to both method. Classfull have class (implicit mask) in advance, while classless have no class (implicit mask).

[vrsf555]

So, in Classful addressing, the address has 3 parts, network, subnet, and host? or should be said: In classful addressing, IP address is divided into two parts: host id and network

[Dan Lukes · Accepted solution]

Almost true. In classful mode the explicit mas may not be used. There are only two parts (network and host) in such case.

May be this page will help you.

Note the classful addressing scheme is rather historic. I bet you will never see network with classful addressing scheme used. It's about fifteen years since I've seen this kind of thing for the last time