ZyXEL Communications VFG6005, User Manual

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29-bit mask 11111111 11111111 11111111 11111000 255.255.255.248
.
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:
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
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 usual
ly specified by writing a ―/‖ followed by the number of bits in the mask after the address.