Initial Configuration
2-8 Vipersat CDM-570/570L User Guide
Configure the Route Table
Routing in a Vipersat Network
CDM-570/570L modem/routers operating in Vipersat mode do not use the
small or large network described in the CDM-570/570L Installation and Opera-
tion Manual. There is no HDLC address in a Vipersat network; instead, the
CDM-570/570L role designation — Hub or Remote, Expansion unit or not —
determines routing rules that prevent multicast loops. This simplifies the config-
uration of a Vipersat network.
Because satellite networks are often used as extensions for access to services
such as the Internet or the PSTN, they lend themselves quite readily to private
addressing. For example, to provide Internet access to the satellite network, only
the Hub requires a public IP address in order for the entire satellite network that
is controlled by the Hub to have access to the Internet backbone. Utilizing
Network Address Translation (NAT), the administrator can effectively address
the network using a minimum number of static route statements.
Example:
The IP address 172.16.0.0 is the private address network number for class B
networks. If there is a router at the Hub with a connection to the Internet, the
operator can define the local network as a class B. If the operator splits the Class
B in half and points the upper half toward the satellite there will be over 16000
usable addresses at the Hub as well as at the Remotes. For details on IP address-
ing, refer to Appendix A, "Network Addressing".
By putting the one route statement “Remotes 172.16.128.0/17 Wan to Sat” in
the TDM Hub modem, and by using the route statement “GW 0.0.0.0/0 Wan to
Sat” at each of the remote modems, the network will successfully route packets.
The remotes can then be sub-netted as class C networks or below. Additional
routers at the remotes can be added for unusually large sites, allowing an addi-
tional layer of NAT without requiring any more explicit routing within the
Vipersat Modem/Routers.
Refer to the CDM-570/570L Installation and Operation Manual for additional
information on entering routes.
Creating the Routes
The following procedure outlines the basic route structure that the target
CDM-570/570L will require for its role in the network. One of the key routes