Draytek VigorSwitch G2240, Руководство пользователя, Страница: 22 / 156

VigorSwitch G2240 User’s Guide 16
1 1 . . 5 5 . . 6 6 I I P P A A d d d d r r e e s s s s A A s s s s i i g g n n m m e e n n t t
For IP address configuration, there are three parameters needed to be filled in. They are IP
address, Subnet Mask, Default Gateway and DNS.
IP address:
The address of the network device in the network is used for internetworking
communication. Its address structure looks is shown below. It is “classful” because it is
split into predefined address classes or categories.
Each class has its own network range between the network identifier and host identifier in
the 32 bits address. Each IP address comprises two parts: network identifier (address) and
host identifier (address). The former indicates the network where the addressed host resides,
and the latter indicates the individual host in the network which the address of host refers to.
And the host identifier must be unique in the same LAN. Here the term of IP address we
used is version 4, known as IPv4.
Network identifier Host identifier
With the classful addressing, it divides IP address into three classes, class A, class B and
class C. The rest of IP addresses are for multicast and broadcast. The bit length of the
network prefix is the same as that of the subnet mask and is denoted as IP address/X, for
example, 192.168.1.0/24. Each class has its address range described below.
Class A:
Address is less than 126.255.255.255. There are a total of 126 networks can be defined
because the address 0.0.0.0 is reserved for default route and 127.0.0.0/8 is reserved for
loopback function.
Class B:
IP address range between 128.0.0.0 and 191.255.255.255. Each class B network has a
16-bit network prefix followed 16-bit host address. There are 16,384 (2^14)/16 networks
able to be defined with a maximum of 65534 (2^16 –2) hosts per network.
Class C:
IP address range between 192.0.0.0 and 223.255.255.255. Each class C network has a
24-bit network prefix followed 8-bit host address. There are 2,097,152 (2^21)/24 networks
able to be defined with a maximum of 254 (2^8 –2) hosts per network.
32 bits