OSPF path selection methods

[g.peart]

If an OSPF router as two equal costs paths to the default but one path crosses

fewer areas, does the path that crosses fewest areas become the installed route.

I include a topology, and in it RtrA goes via RtrC to get to the default

rather than using RtrB, and the only difference is the number of areas

traversed, when all costs are equal on the interfaces.

any answers,

thanks.

[Reza Sharifi]

OSPF prefers intra area routes over inter area routes.  So Rtr-A goes through Rtr-C to Rtr-D because they are all in the same area (0)

HTH

Reza

[g.peart]

I understand that bit now because when I shut down the link

between RtrA and RtrC the route to RtrD becomes type O IA

in the routing table rather then the original of just type 'O'.

I have now changed the Link RtrA-RtrB to Area 0 and RtrA

is showing two equal cost paths to the default in the routing table

via RtrB or RtrC but the Gateway of last resort is only showing

one of these: RtrC, why does that occur, is only one route being used

for the default ?