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P-660H/HW/W-T Series User’ Guide
377
Appendix D
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 125
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 126
“Natural” Masks
CLASS
NATURAL MASK
A
255.0.0.0
B
255.255.0.0
C
255.255.255.0
Содержание P-660H - VERSION 3.40
Страница 1: ...P 660H HW W T Series ADSL 2 Gateway User s Guide Version 3 40 6 2005...
Страница 9: ...P 660H HW W T Series User Guide 9 Customer Support...
Страница 31: ...P 660H HW W T Series User Guide 31 List of Figures...
Страница 37: ...P 660H HW W T Series User Guide 37 List of Tables...
Страница 41: ...P 660H HW W T Series User Guide 41 Introduction to DSL...
Страница 61: ...P 660H HW W T Series User Guide 61 Chapter 3 Wizard Setup for Internet Access...
Страница 89: ...P 660H HW W T Series User Guide 89 Chapter 5 Wireless LAN...
Страница 131: ...P 660H HW W T Series User Guide 131 Chapter 10 Firewalls...
Страница 161: ...P 660H HW W T Series User Guide 161 Chapter 13 Remote Management Configuration...
Страница 175: ...P 660H HW W T Series User Guide 175 Chapter 14 Universal Plug and Play UPnP...
Страница 181: ...P 660H HW W T Series User Guide 181 Chapter 15 Logs Screens...
Страница 195: ...P 660H HW W T Series User Guide 195 Chapter 16 Media Bandwidth Management Advanced Setup...
Страница 207: ...P 660H HW W T Series User Guide 207 Chapter 17 Maintenance...
Страница 217: ...P 660H HW W T Series User Guide 217 Chapter 19 Menu 1 General Setup...
Страница 221: ...P 660H HW W T Series User Guide 221 Chapter 20 Menu 2 WAN Backup Setup...
Страница 225: ...P 660H HW W T Series User Guide 225 Chapter 21 Menu 3 LAN Setup...
Страница 229: ...P 660H HW W T Series User Guide 229 Chapter 22 Wireless LAN Setup...
Страница 235: ...P 660H HW W T Series User Guide 235 Chapter 23 Internet Access...
Страница 249: ...P 660H HW W T Series User Guide 249 Chapter 25 Static Route Setup...
Страница 253: ...P 660H HW W T Series User Guide 253 Chapter 26 Bridging Setup...
Страница 269: ...P 660H HW W T Series User Guide 269 Chapter 27 Network Address Translation NAT...
Страница 285: ...P 660H HW W T Series User Guide 285 Chapter 29 Filter Configuration...
Страница 305: ...P 660H HW W T Series User Guide 305 Chapter 32 System Information and Diagnosis...
Страница 317: ...P 660H HW W T Series User Guide 317 Chapter 33 Firmware and Configuration File Maintenance...
Страница 323: ...P 660H HW W T Series User Guide 323 Chapter 34 System Maintenance...
Страница 327: ...P 660H HW W T Series User Guide 327 Chapter 35 Remote Management...
Страница 337: ...P 660H HW W T Series User Guide 337 Chapter 36 IP Policy Routing...
Страница 341: ...P 660H HW W T Series User Guide 341 Chapter 37 Call Scheduling...
Страница 353: ...P 660H HW W T Series User Guide 353 Chapter 38 Troubleshooting Figure 232 Security Setting ActiveX Controls...
Страница 357: ...P 660H HW W T Series User Guide 357 Appendix A...
Страница 359: ...P 660H HW W T Series User Guide 359 Appendix B...
Страница 383: ...P 660H HW W T Series User Guide 383 Appendix D...
Страница 387: ...P 660H HW W T Series User Guide 387 Appendix F...
Страница 393: ...P 660H HW W T Series User Guide 393 Appendix G...
Страница 397: ...P 660H HW W T Series User Guide 397 Appendix H...
Страница 400: ...P 660H HW W T Series User Guide Appendix I 400...
Страница 401: ...P 660H HW W T Series User Guide 401 Appendix I...
Страница 455: ...P 660H HW W T Series User Guide 455 Appendix M...