Hughes DIRECWAY DW4020 - Manual (Page 88)

Appendix B • The Internet and the DW4020
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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.
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.”
Figure 52: Typical DW4020 connection scheme
T0091104.FH9
G-23789 F
07/23/02
IP Address 170.15.100.2 170.15.100.3 170.15.100.4 170.15.100.5
LAN IP Address: 170.15.100.1
LAN
IP Address
170.15.99.1
Gateway
IP Address
170.15.xxx.yyy
HNS Network Operations Center
(NOC)
Hub
GWH
ITU
IRU
USB
25 Pin
Connector
From LAN
DW4020