O'Reilly logo

BSCI Exam Cram™ 2 (Exam 642-801) by Ed Tittel, Michael J. Shannon

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Classless Interdomain Routing

Classless Interdomain Routing (CIDR) is referenced in RFCs 1518, 1519, and 2050, which were developed for Internet service providers (ISPs) so they could aggregate contiguous blocks for efficient addressing schemes. With the classful system of allocating IP addresses, anyone who needed more than 254 host addresses was often forced into a public Class B address, providing more than 65,500 host addresses. Many companies and organizations wasted even more addresses by using only a fraction of their 16 million host Class A addresses. As a matter of fact, only a small percentage of the allocated Class A and Class B address space has been actually assigned to host computers on the Internet.

It became clear that by circumventing ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required