![ZyXEL Communications VSG-1200 V2 Скачать руководство пользователя страница 270](http://html.mh-extra.com/html/zyxel-communications/vsg-1200-v2/vsg-1200-v2_user-manual_944384270.webp)
P-660HW-T v2 User’s Guide
Appendix H IP Addresses and Subnetting
270
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 bits. If a bit in the subnet mask 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 like IP addresses. 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 leftmost bit of the mask, followed by a continuous sequence of zeros, for a total number of
32 bits.
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 mask 255.255.255.128.
The following table shows all possible subnet masks for a class “C” address using both
notations.
Table 102
“Natural” Masks
CLASS
NATURAL MASK
A
255.0.0.0
B
255.255.0.0
C
255.255.255.0
Table 103
Alternative Subnet Mask Notation
SUBNET MASK
SUBNET MASK “1” BITS
LAST OCTET BIT VALUE
DECIMAL
255.255.255.0
/24
0000 0000
0
255.255.255.128
/25
1000 0000
128
255.255.255.192
/26
1100 0000
192
255.255.255.224
/27
1110 0000
224
Содержание VSG-1200 V2
Страница 1: ...VSG 1200 V2 Vantage Service Gateway User s Guide Version 1 00 10 2006 Edition 1 ...
Страница 6: ...VSG 1200 V2 User s Guide Safety Warnings 6 ...
Страница 19: ...VSG 1200 V2 User s Guide 19 Table of Contents ...
Страница 25: ...VSG 1200 V2 User s Guide 25 List of Figures ...
Страница 29: ...VSG 1200 V2 User s Guide 29 List of Tables ...
Страница 37: ...VSG 1200 V2 User s Guide 37 Chapter 1 Getting to Know Your VSG ...
Страница 49: ...VSG 1200 V2 User s Guide 49 Chapter 3 The Web Configurator ...
Страница 55: ...VSG 1200 V2 User s Guide 55 Chapter 4 Initial Setup Example ...
Страница 69: ...VSG 1200 V2 User s Guide 69 Chapter 6 LAN and WAN Setup ...
Страница 83: ...VSG 1200 V2 User s Guide 83 Chapter 9 Authentication Figure 32 System Settings Authentication ...
Страница 111: ...VSG 1200 V2 User s Guide 111 Chapter 12 Dynamic Subscriber Accounts ...
Страница 115: ...VSG 1200 V2 User s Guide 115 Chapter 13 Port Location Mapping ...
Страница 147: ...VSG 1200 V2 User s Guide 147 Chapter 16 Bandwidth Management ...
Страница 167: ...VSG 1200 V2 User s Guide 167 Chapter 22 Static Route ...
Страница 175: ...VSG 1200 V2 User s Guide 175 Chapter 24 Syslog ...
Страница 181: ...VSG 1200 V2 User s Guide 181 Chapter 26 SNMP ...
Страница 195: ...VSG 1200 V2 User s Guide 195 Chapter 28 System Status ...
Страница 213: ...VSG 1200 V2 User s Guide 213 Chapter 31 SSL Certificate ...
Страница 229: ...VSG 1200 V2 User s Guide 229 Chapter 32 Using The SMT ...
Страница 239: ...VSG 1200 V2 User s Guide 239 Appendix B IP Address Assignment Conflicts ...
Страница 241: ...VSG 1200 V2 User s Guide 241 Appendix C Subscriber Login ...
Страница 245: ...VSG 1200 V2 User s Guide 245 Appendix D Vendor Specific Attributes ...
Страница 255: ...VSG 1200 V2 User s Guide 255 Appendix F Cable Types and Cable Pin Assignments ...
Страница 267: ...VSG 1200 V2 User s Guide 267 Appendix G Setting up Your Computer s IP Address ...