DW4020s provide connections
The DW4020 provides connectivity from a satellite network to multiple computers.
From the point of view of the individual computer user, the DW4020 provides the link to the outside world. DW4020s direct data traffic by inspecting the IP addresses. A DW4020 is assigned two IP addresses, one in each network that it links.
Figure 52 illustrates a typical connection scheme for the DW4020.
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LAN IP Address: 170.15.100.1
DW4020
LAN
IP Address | 170.15.100.2 | 170.15.100.3 | 170.15.100.4 | 170.15.100.5 |
T0091104.FH9
Hub
IP Address 
170.15.99.1
Gateway
IP Address
170.15.xxx.yyy
HNS Network Operations Center
(NOC)
Figure 52: Typical DW4020 connection scheme
Subnet mask The subnet mask defines the part of the IP address used to identify computers on the same LAN from computers in other departments or elsewhere in the world. Computers on the same LAN can send messages directly to each other. Messages for other LANs and the rest of the world need to be sent through a router. In a scheme where the first three bytes identify the LAN network, the subnet mask is 255.255.255.0. The decimal number 255 corresponds to the binary number 11111111. In IP address notation, 0 is interpreted to mean “this.”
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