RuggedCom RuggedRouter RX1100 - Manual (Page 164)

17. Configuring Dynamic Routing
Revision 1.14.3 164 RX1000/RX1100™
17.1.5.10. Administrative Distances
The router may work with different routing protocols at the same time, as well as employing local
interface and statically assigned routes. An administrative distance, (from 0 to 255) is a rating of
the trustworthiness of a routing information source. For a given route, the protocol having the lowest
administrative distance will be chosen. By default the distances for a connected interface is 0 and
for a static route is 1. By default, OSPF will set an administrative distance of 110 and RIP will set
a distance of 120.
17.1.6. OSPF And VRRP Example Network
This network consists of three routers connected in a ring with T1/E1 links. Router 1 and 2 and the
switched network represent a remote site in which the routers supply a redundant gateway to the
hosts via VRRP and the T1/E1 links supply a redundant network connection to the rest of the network.
Figure 17.1. OSPF and VRRP Example
17.1.6.1. Area And Subnets
As the OSPF design is simple, an area of 0 is used. The three point-to-point T1/E1 links are placed
in the area by adding 1.1.1.0/24 to it. Router 1 and 2 will include their Ethernet links by adding subnet
1.1.2.0/24 to their area descriptions. Router 3 must also include 2.2.2.0/24 in its area description so
that its existence is advertised.
The point-to-point T1/E1 interfaces and Ethernet interfaces on Router 1 and 2 must be made
active. The Ethernet interface on Router 3 can be left passive since it does not participate in OSPF
advertisements.