Appendix B IP Addresses and Subnetting
STB-1001S User’s Guide
117
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.
Network Size
The size of the network number determines the maximum number of possible hosts you can
have on your network. The larger the number of network number bits, the smaller the number
of remaining host ID bits.
An IP address with host IDs of all zeros is the IP address of the network (192.168.1.0 with a
24-bit subnet mask, for example). An IP address with host IDs of all ones is the broadcast
address for that network (192.168.1.255 with a 24-bit subnet mask, for example).
As these two IP addresses cannot be used for individual hosts, calculate the maximum number
of possible hosts in a network as follows:
Notation
Since the mask is always a continuous number of ones beginning from the left, followed by a
continuous number of zeros for the remainder of the 32 bit mask, you can simply specify the
number of ones instead of writing the value of each octet. This is usually specified by writing
a “/” followed by the number of bits in the mask after the address.
For example, 192.1.1.0 /25 is equivalent to saying 192.1.1.0 with subnet mask
255.255.255.128.
The following table shows some possible subnet masks using both notations.
Table 26
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 mask
11111111
11111111
11111111
00000000
255.255.255.0
29-bit mask
11111111
11111111
11111111
11111000
255.255.255.248
Table 27
Maximum Host Numbers
SUBNET MASK
HOST ID SIZE
MAXIMUM NUMBER OF HOSTS
8 bits
255.0.0.0
24 bits
2
24
– 2
16777214
16 bits
255.255.0.0
16 bits
2
16
– 2
65534
24 bits
255.255.255.0
8 bits
2
8
– 2
254
29 bits
255.255.255.248 3 bits
2
3
– 2
6
Table 28
Alternative Subnet Mask Notation
SUBNET MASK
ALTERNATIVE
NOTATION
LAST OCTET
(BINARY)
LAST OCTET
(DECIMAL)
255.255.255.0
/24
0000 0000
0
255.255.255.128
/25
1000 0000
128
Summary of Contents for STB-1001S
Page 2: ......
Page 7: ...Safety Warnings STB 1001S User s Guide 7 ...
Page 8: ...Safety Warnings STB 1001S User s Guide 8 ...
Page 10: ...Contents Overview STB 1001S User s Guide 10 ...
Page 14: ...Table of Contents STB 1001S User s Guide 14 Index 135 ...
Page 18: ...List of Figures STB 1001S User s Guide 18 ...
Page 20: ...List of Tables STB 1001S User s Guide 20 ...
Page 22: ...22 ...
Page 26: ...Chapter 1 Introducing the STB STB 1001S User s Guide 26 ...
Page 36: ...Chapter 2 The Menu System STB 1001S User s Guide 36 ...
Page 50: ...Chapter 4 Troubleshooting STB 1001S User s Guide 50 ...
Page 56: ...56 ...
Page 72: ...Chapter 7 Руководство пользователя системы STB 1001S 72 ...
Page 86: ...Chapter 9 Руководство пользователя системы STB 1001S 86 ...
Page 90: ...Chapter 10 Руководство пользователя системы STB 1001S 90 ...
Page 92: ...92 ...
Page 114: ...Appendix A Setting up Your Computer s IP Address STB 1001S User s Guide 114 ...
Page 128: ...Appendix C Legal Information STB 1001S User s Guide 128 ...
Page 134: ...Appendix D Customer Support STB 1001S User s Guide 134 ...