Chapter Nine: Advanced Installations | IP routes 123 |
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Why routes are needed
Data on an IP network is carried in small packages called datagrams. Each datagram contains the IP address of its source and destination. In order to send datagrams to their proper destination, the DIVA LAN ISDN Modem requires a list of destinations and the addresses that are associated with it. This information is stored in a route. Since more than one route is generally required, they are grouped together in a routing table. Each time the DIVA LAN ISDN Modem sends or received a datagram, it consults the routing table to determine the target destination for the datagram.
Single connection
Consider the following scenario:
192.168.1.5 | 192.168.1.4 | 192.168.1.3 | 192.168.1.2 |
Internet
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192.168.1.1 |
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| ISP profile | ||||||||
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| Address negotiated with ISP | |||||||||
| DIVA |
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| 212.182.22.39 | |||
| ISDN |
| Ethernet | |||||||||
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| LAN ISDN Modem |
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| FAULT POWER | |||
| B1 | B2 D LINK | E1 E2 E3 E4/C | |||||||||
DIVA LAN ISDN Modem
ISP |
ISDN
Network
Routes
Route 1 = 0.0.0.0 with a mask of 0. Assigned to Internet connection.
Since there is only one destination for outgoing data (the Internet), only one route is required. This route needs to match all addresses. The special address 0.0.0.0 does this. The same would be true for a Corporate connection. If you want to route all data to the corporate network, specify a single route using the special address 0.0.0.0.
There can be only one default route on the DIVA LAN ISDN Modem. The default route always uses the special address 0.0.0.0.
