
IP Concepts, Terminology, and Features
1-7
Supernet Addressing and Classless Interdomain Routing (CIDR)
A supernet is a group of networks identified by contiguous network addresses. IP
service providers can assign customers blocks of contiguous addresses to define
supernets as needed.
Each supernet has a unique supernet address that consists of the upper bits shared
by all of the addresses in the contiguous block. For example, consider the
following block of contiguous 32-bit addresses (192.32.0.0 through 192.32.7.0 in
decimal notation).
10 255.255.255.192 1,022 62
11 255.255.255.224 2,046 30
12 255.255.255.240 4,094 14
13 255.255.255.248 8,190 6
14 255.255.255.252 16,382 2
Class C
2 255.255.255.192 2 62
3 255.255.255.224 6 30
4 255.255.255.240 14 14
5 255.255.255.248 30 6
6 255.255.255.252 62 2
Table 1-1. Subnet Masks for Class B and Class C Addresses
(continued)
Number of Bits Subnet Mask
Number of
Subnets
(Recommended)
Number of Hosts
per Subnet
11000000 00100000 00000000 00000000
11000000 00100000 00000001 00000000
11000000 00100000 00000010 00000000
11000000 00100000 00000011 00000000
11000000 00100000 00000100 00000000
11000000 00100000 00000111 00000000
11000000 00100000 00000101 00000000
11000000 00100000 00000110 00000000
Comentários a estes Manuais