Default IP route
Default IP routes are advertised
by border routers to its peers. So this allows peers to use the advertised
router as a next hop for destinations which are not listed in the
routing table. This feature allows routers which are not able to maintain
a huge list of routing entries in their routing table to use the default
traffic to the advertised border router. You do not have to configure
the static routes on the routers which are not able to maintain the
routing table entries.
The IP Manager monitors the default
route entry on the border router, that is, the border routers are
polled to check only the default route entry and not the entire routing
table, and when the default route entry is missing, the IP Manager
generates an event known as
MissingDefaultRoute
. This
reduces the amount of SNMP request processing that the router has
to perform.The OID which is used for this feature is
ipRouteDest-1.3.6.1.2.1.4.21.1.1
. Normally the default IP
route is 0.0.0.0 which gets advertised using the update message by
either the border router speaker to all its peers. The update message
also contains the next hop attribute which is the IP address of the
border router. That is how the peers know about the border router
speaker.