User`s guide

Table Of Contents
MWR211 User’s Guide
233
Table 73 Subnet Mask - Identifying Network Number
1ST
OCTET:
(192)
2ND
OCTET:
(168)
3RD
OCTET:
(1)
4TH
OCTET
(2)
IP Address (Binary) 11000000 10101000 00000001 00000010
Subnet Mask (Binary) 11111111 11111111 11111111 00000000
Network Number 11000000 10101000 00000001
Host ID 00000010
By convention, subnet masks always consist of a continuous sequence of ones
beginning from the leftmost bit of the mask, followed by a continuous sequence
of zeros, for a total number of 32 bits.
Subnet masks can be referred to by the size of the network number part (the bits
with a “1” value). For example, an “8-bit mask” means that the first 8 bits of the
mask are ones and the remaining 24 bits are zeroes.
Subnet masks are expressed in dotted decimal notation just like IP addresses.
The following examples show the binary and decimal notation for 8-bit, 16-bit,
24-bit and 29-bit subnet masks
Table 74 Subnet Masks
BINARY
DECIMAL
1ST
OCTET
2ND
OCTET
3RD
OCTET
4TH
OCTET
8-bit mask 11111111 00000000 00000000 00000000 255.0.0.0
16-bit
mask
11111111 11111111 00000000 00000000 255.255.0.0
24-bit 11111111 11111111 11111111 00000000 255.255.255.0