RuggedCom RuggedRouter RX1100 - Manual (Page 163)

17. Configuring Dynamic Routing
Revision 1.14.3 163 RX1000/RX1100™
Note
The default setting of Passive Interface Default means that you must explicitly configure interfaces
active before OSPF will attempt to use them.
17.1.5.5. Redistributing Routes
Routes for subnets which are directly connected to the router but are not part of the OSPF area or
RIP or BGP networks can be advertised if "redistribute connected" is enabled in the OSPF, RIP, or
BGP Global Parameters. Static routes and routes handled by the kernel can also be redistributed if
"redistribute static" and "redistribute kernel" are enabled, respectively.
17.1.5.6. Link Detect
Link detection is enabled for active network interfaces, which ensures that the appropriate routing
daemon is notified when an interface goes down, and stops advertising subnets associated with that
interface. The routing daemon resumes advertising the subnet when the link is restored. This allows
routing daemons to detect link failures more rapidly (as the router does not have to wait for a "dead
interval" to time out). Link Detect also causes "redistributed" routes to start and stop being advertised
based on the status of their interface links.
17.1.5.7. Configuring OSPF Link Costs
Link cost is used when multiple links can reach a given destination, to determine which route to use.
OSPF will (by default) assign the same cost to all links unless provided with extra information about the
links. Each interface is assumed to be 10Mbit unless told otherwise in the Core Interface configuration.
The reference bandwidth for link cost calculations is 100Mbit by default in the OSPF Global
Parameters. The reference bandwidth divided by the link bandwidth gives the default cost for a link,
which by default is 10. If a specific bandwidth is assigned to each link, the costs will take this into
account.
It is also possible to manually assign a cost to using a link in the OSPF Interface Configuration for each
interface for cases where the speed of the link is not desired as the method for choosing the best link.
17.1.5.8. OSPF Authentication
OSPF authentication is used when it is desirable to prevent unauthorized routers from joining the
OSPF network. By enabling authentication and configuring a shared key on all the routers, only routers
which have the same authentication key will be able to send and receive advertisements within the
OSPF network. Authentication adds a small overhead due to the encryption of messages, so is not
to be preferred on completely private networks with controlled access.
17.1.5.9. RIP Authentication
RIP authentication is used when it is desirable to prevent unauthorized routers from joining the
network. RIP authentication is supported by per-interface configuration or the use of key-chains.
Separate key chains spanning different groups of interfaces and having separate lifespans are
possible. By enabling authentication and configuring a shared key on all the routers, only routers
which have the same authentication key will be able to send and receive advertisements within the
RIP network.