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156 Chapter 5: IP Addressing
NOTE
These masks assume Class C networks.
NOTE
The local address is not considered an available address. Cisco offers a feature called ip subnet-
zero that allows a local address to be accessed. The concept of ip subnet-zero is beyond the
scope of this chapter and is not discussed in this book
Table 5-6 lists the available network addresses for subnet mask .240.
Table 5-5
Mask 224
Network
Available Addresses
Local Address
Broadcast Address
0­31
1­30
0
31
32­63
33­62
32
63
64­95
65­94
64
95
128­159
129­158
128
159
160­191
161­190
160
191
192­223
193­222
192
223
224­255
225­254
224
255
Table 5-6
Mask 240
Network
Available Addresses
Network
Available Addresses
0­15
Local address: 0
Broadcast address: 15
1­14
128­143
Local address: 129
Broadcast address: 142
B142
129­142
16­31
Local address: 16
Broadcast address: 31
17­30
144­159
Local address: 145
Broadcast address: 158
145­158
32­47
Local address: 32
Broadcast address: 47
33­46
160­175
Local address: 160
Broadcast address: 175
161­174
87200333.book Page 156 Wednesday, August 22, 2001 2:37 PM