However if we go back to the previous example
note that in this case OSPF and RIP are advertising
the same route network 10.0.0.0/8 is advertised
by both New York and San Jose and thus administrative distance is chosen
because the same route can’t be put twice into the routing table.
The router has to choose the best route
and in this case, administrative distance is used
as the tie breaker between OSPF and RIP.
So in summary administrative distance is only used
if multiple routing protocols are trying to put the same route
into the Routing Information Base or RIP also called the routing table
In this example once again the 3 routes
are seen as 3 separate and distinct routes.
All 3 routes are put into the routing table
and the routing decision is based on longest match or best match.
So network 10.1.1.0/27 has the longest match
so it’s deemed to be the best route.
Traffic is forwarded to router 1
even though RIP has a higher administrative distance when compared to OSPF.