Wellink Corporation NEOBIT1014VA Manuale Utente
NEOBIT 1014VA ADSL Router User’s Guide
Appendix A. IP Addresses, Network Masks, and Subnets
uses the remaining 7 bits in field4 for its host IDs, which range from
0 to 127 (instead of the usual 0 to 255 for a class C address).
0 to 127 (instead of the usual 0 to 255 for a class C address).
Similarly, to split a class C network into four subnets, the mask is:
255.255.255.192 or 11111111. 11111111. 11111111.11000000
The two extra bits in field4 can have four values (00, 01, 10, 11), so
there are four subnets. Each subnet uses the remaining six bits in
field4 for its host IDs, ranging from 0 to 63.
there are four subnets. Each subnet uses the remaining six bits in
field4 for its host IDs, ranging from 0 to 63.
Note
Sometimes a subnet mask does not specify any additional
network ID bits, and thus no subnets. Such a mask is called a
default subnet mask. These masks are:
network ID bits, and thus no subnets. Such a mask is called a
default subnet mask. These masks are:
Class A:
255.0.0.0
Class B:
255.255.0.0
Class C:
255.255.255.0
These are called default because they are used when a network is
initially configured, at which time it has no subnets.
initially configured, at which time it has no subnets.