Appendix D IP Addresses and Subnetting
GS-2724 User’s Guide
321
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 104
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 105
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 106
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 GS-2724
Page 1: ...www zyxel com GS 2724 Ethernet Switch User s Guide Version 3 70 4 2007 Edition 1 ...
Page 2: ......
Page 7: ...Safety Warnings GS 2724 User s Guide 7 ...
Page 8: ...Safety Warnings GS 2724 User s Guide 8 ...
Page 22: ...Table of Contents GS 2724 User s Guide 22 ...
Page 30: ...List of Tables GS 2724 User s Guide 30 ...
Page 32: ...32 ...
Page 36: ...Chapter 1 Getting to Know Your Switch GS 2724 User s Guide 36 ...
Page 40: ...Chapter 2 Hardware Installation and Connection GS 2724 User s Guide 40 ...
Page 46: ...Chapter 3 Hardware Overview GS 2724 User s Guide 46 ...
Page 48: ...48 ...
Page 58: ...Chapter 4 The Web Configurator GS 2724 User s Guide 58 ...
Page 64: ...Chapter 5 Initial Setup Example GS 2724 User s Guide 64 ...
Page 70: ...Chapter 6 System Status and Port Statistics GS 2724 User s Guide 70 ...
Page 84: ...84 ...
Page 94: ...Chapter 8 VLAN GS 2724 User s Guide 94 Figure 36 Port Based VLAN Setup All connected ...
Page 126: ...Chapter 16 Port Authentication GS 2724 User s Guide 126 ...
Page 130: ...Chapter 17 Port Security GS 2724 User s Guide 130 ...
Page 136: ...Chapter 18 Classifier GS 2724 User s Guide 136 Figure 58 Classifier Example ...
Page 139: ...Chapter 19 Policy Rule GS 2724 User s Guide 139 Figure 59 Policy ...
Page 145: ...Chapter 20 Queuing Method GS 2724 User s Guide 145 ...
Page 146: ...Chapter 20 Queuing Method GS 2724 User s Guide 146 ...
Page 152: ...Chapter 21 VLAN Stacking GS 2724 User s Guide 152 ...
Page 166: ...166 ...
Page 183: ...Chapter 27 DHCP GS 2724 User s Guide 183 Figure 89 DHCP Relay Configuration Example ...
Page 184: ...Chapter 27 DHCP GS 2724 User s Guide 184 ...
Page 186: ...186 ...
Page 210: ...Chapter 31 Syslog GS 2724 User s Guide 210 ...
Page 224: ...Chapter 36 Routing Table GS 2724 User s Guide 224 ...
Page 228: ...228 ...
Page 262: ...Chapter 38 Introducing Commands GS 2724 User s Guide 262 ...
Page 296: ...Chapter 42 IEEE 802 1Q Tagged VLAN Commands GS 2724 User s Guide 296 ...
Page 300: ...Chapter 44 Routing Domain Command Examples GS 2724 User s Guide 300 ...
Page 304: ...304 ...
Page 312: ...Appendix B Changing a Fuse GS 2724 User s Guide 312 ...
Page 332: ...Appendix E Common Services GS 2724 User s Guide 332 ...
Page 336: ...Appendix F Legal Information GS 2724 User s Guide 336 ...
Page 348: ...Index GS 2724 User s Guide 348 ...