DATACOM TEXTRON M.A.Ch.10/100, Руководство пользователя

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M.A.Ch.10/100 Diagnostic Analyzer 09/00
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Subnet Design Calculator
The
Subnet Design Calculator
is used to help design an IP network. Typically, a
company will be given a range of IP addresses from their Internet Service Provider (ISP)
to be used on their network. The ranges of IP addresses traditionally have been classified
as:
Class A
- all addresses less than 127.0.0.0
Class B
- all addresses between 128.0.0.0 to 191.255.255.255
Class C
- all addresses 192.0.0.0 and above
This distinction is becoming less important, but it is used in the
M.A.Ch.10/100
designer
in order to establish the default Subnet Mask.
Subnet Mask
Subnet Mask is used to segment the range of IP addresses into different network
segments. This reduces the amount of IP traffic on a network. If all IP addresses were on
the same network, the network would be unusable. The Subnet Mask allows your IP
traffic to be isolated to a single network.
In order to go outside the network you must go through a gateway. This gateway keeps
all outside traffic from being seen on your network unless it is addressed specifically to
someone on your network. It also keeps all of your IP traffic from being seen outside
your network unless it is addressed to someone on the outside.
The following screen shows the
M.A.Ch.10/100
Subnet Designer. Start by entering the
Host IP Address
. A default Subnet Mask is produced according to the first segment of
the Host IP address. This particular IP Address is a
Class C
, which allows for a maximum
of 256 IP addresses. But on each IP network there has to be a network address and a
broadcast address. Therefore, each time you add a subnet, you reduce the number of
available IP addresses by two.
Subnet Design
This particular example has two subnets that show the Subnet Mask as
255.255.255.128
.
Because the fourth segment of the IP address is
100
, the Network Address is shown as
212.132.115.000
for this particular IP address and the Broadcast address is
212.132.115.127
. All addresses between the network address and broadcast address are
available to be used by any host.