Prestige 660RU-Tx Series User’s Guide
261
Appendix C
Since the first octet of a class “A” IP address must contain a “0”, the first octet of a class “A”
address can have a value of 0 to 127.
Similarly the first octet of a class “B” must begin with “10”, therefore the first octet of a class
“B” address has a valid range of 128 to 191. The first octet of a class “C” address begins with
“110”, and therefore has a range of 192 to 223.
Subnet Masks
A subnet mask is used to determine which bits are part of the network number, and which bits
are part of the host ID (using a logical AND operation). A subnet mask has 32 is a “1” then
the corresponding bit in the IP address is part of the network number. If a bit in the subnet
mask is “0” then the corresponding bit in the IP address is part of the host ID.
Subnet masks are expressed in dotted decimal notation just as IP addresses are. The “natural”
masks for class A, B and C IP addresses are as follows.
Subnetting
With subnetting, the class arrangement of an IP address is ignored. For example, a class C
address no longer has to have 24 bits of network number and 8 bits of host ID. With
subnetting, some of the host ID bits are converted into network number bits. By convention,
subnet masks always consist of a continuous sequence of ones beginning from the left most bit
of the mask, followed by a continuous sequence of zeros, for a total number of 32 bits.
Table 84
Allowed IP Address Range By Class
CLASS
ALLOWED RANGE OF FIRST OCTET
(BINARY)
ALLOWED RANGE OF FIRST OCTET
(DECIMAL)
Class A
0
0000000 to
0
1111111
0 to 127
Class B
10
000000 to
10
111111
128 to 191
Class C
110
00000 to
110
11111
192 to 223
Class D
1110
0000 to
1110
1111
224 to 239
Table 85
“Natural” Masks
CLASS
NATURAL MASK
A
255.0.0.0
B
255.255.0.0
C
255.255.255.0
Содержание ADSL2+ Ethernet/USB Gateway 660RU-Tx Series
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Страница 30: ...Prestige 660RU Tx Series User s Guide 29 Introduction to DSL ...
Страница 38: ...Prestige 660RU Tx Series User s Guide 37 Chapter 1 Getting To Know Your Prestige ...
Страница 56: ...Prestige 660RU Tx Series User s Guide 55 Chapter 4 Password Setup ...
Страница 64: ...Prestige 660RU Tx Series User s Guide 63 Chapter 5 LAN Setup ...
Страница 74: ...Prestige 660RU Tx Series User s Guide 73 Chapter 6 WAN Setup ...
Страница 86: ...Prestige 660RU Tx Series User s Guide 85 Chapter 7 Network Address Translation NAT Screens ...
Страница 94: ...Prestige 660RU Tx Series User s Guide 93 Chapter 10 Remote Management Configuration ...
Страница 108: ...Prestige 660RU Tx Series User s Guide 107 Chapter 11 Universal Plug and Play UPnP ...
Страница 124: ...Prestige 660RU Tx Series User s Guide 123 Chapter 13 Introducing the SMT ...
Страница 128: ...Prestige 660RU Tx Series User s Guide 127 Chapter 14 Menu 1 General Setup ...
Страница 132: ...Prestige 660RU Tx Series User s Guide 131 Chapter 15 Menu 2 WAN Backup Setup ...
Страница 136: ...Prestige 660RU Tx Series User s Guide 135 Chapter 16 Menu 3 LAN Setup ...
Страница 158: ...Prestige 660RU Tx Series User s Guide 157 Chapter 19 Static Route Setup ...
Страница 162: ...Prestige 660RU Tx Series User s Guide 161 Chapter 20 Bridging Setup ...
Страница 178: ...Prestige 660RU Tx Series User s Guide 177 Chapter 21 Network Address Translation NAT ...
Страница 206: ...Prestige 660RU Tx Series User s Guide 205 Chapter 24 System Information and Diagnosis ...
Страница 218: ...Prestige 660RU Tx Series User s Guide 217 Chapter 25 Firmware and Configuration File Maintenance ...
Страница 224: ...Prestige 660RU Tx Series User s Guide 223 Chapter 26 System Maintenance ...
Страница 228: ...Prestige 660RU Tx Series User s Guide 227 Chapter 27 Remote Management ...
Страница 238: ...Prestige 660RU Tx Series User s Guide 237 Chapter 28 IP Policy Routing ...
Страница 242: ...Prestige 660RU Tx Series User s Guide 241 Chapter 29 Call Scheduling ...
Страница 260: ...Prestige 660RU Tx Series User s Guide 259 Appendix B ...
Страница 268: ...Prestige 660RU Tx Series User s Guide 267 Appendix C ...
Страница 272: ...Prestige 660RU Tx Series User s Guide 271 Appendix E ...
Страница 274: ...Prestige 660RU Tx Series User s Guide 273 Appendix F ...
Страница 280: ...Prestige 660RU Tx Series User s Guide 279 Appendix G ...