Safari Books Online is a digital library providing on-demand subscription access to thousands of learning resources.
- Create BookmarkCreate Bookmark
- Create Note or TagCreate Note or Tag
- DownloadDownload
- PrintPrint
Chapter 14. Converting Subnet Masks > Foundation Topics
Foundation Topics
Subnet Mask Conversion
This section describes how to convert between different formats for the subnet mask. You can then use these processes when you practice. If you already know how to convert from one format to the other, go ahead and move to the section, “Practice Converting Subnet Masks.”
Three Mask Formats
Subnet masks may be written as 32-bit binary numbers, but not just any binary number. In particular, the binary subnet mask must follow these rules:
• The value must not interleave 1s and 0s.
• If 1s exist, they are on the left.
• If 0s exist, they are on the right.
For instance, the following values would be illegal. The first is illegal because the value interleaves 0s and 1s, and the second is illegal because it lists 0s on the left and 1s on the right:
