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MultiArea OSPF with 3 Routers doesn't have full connectivity

CCNANewbie
Level 1
Level 1

Hello,

I am struggling to configure the Topology attached bellow and I struggle to obtain full connectivity, to be more exact, I have encountered a behavior, where:
R3 Routing table does not include route to 1.1.1.1/32

R2 Routing table does not include route to 3.3.3.3/32

R1 Routing table does not include a route to 2.2.2.2/32

In other words:
R1 does not have any connectivity to Area 2

R2 does not have any connectivity to Area 3

R3 does not have any connectivity to Area 1

I want to configure it so that full connectivity would be present, that means I could access (ping) each IP address from any point on the network. I feel like I am missing something really important here, Could someone please advise?


NOTE: R1 loopback - Area 1, R2 loopback -Area 2, R3 loopback - Area 3

topology.PNG

My configuration:
R1:

R1.PNG

R2:

R2.PNG

R3:

R3.PNG

5 Replies 5

Hello
configure the link between r1/r2 to be in area 0


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Kind Regards
Paul

Thanks Paul,

This did help, I reconfigured Area 1 -> Area 0, Area 2 -> Area 1 and Area 3 -> Area 2

this will not work optimal but I have workaround for you 
config Lo in each three router 
config this Lo to be in area 0 
this will make ABR advertise L3 to other area even if there is no real Area 0 in your topology. 

friend this workaround, try config Area 0 in real network

Joseph W. Doherty
Hall of Fame
Hall of Fame

Yup, as expected.

"I feel like I am missing something really important here, Could someone please advise?"

Correct, you are missing something really important.

An OSPF router will "know" of an area's topology which its has a "foot" in that area.  But for router's to exchange routes, between areas, which they do not connect to, you need an area zero.

What @MHM Cisco World suggested, I believe will work (as might just doing what he suggested on any two of the three routers).

What's also to be understood, what @MHM Cisco World suggested, and what he notes, this is a "workaround", i.e. not, shall we say, a "best practice" for real networks.

 

BTW, reason I mention what @MHM Cisco World proposed would NOT be best practice, it creates a partitioned area zero, a "bad thing", but for your posted topology, would still work, I believe.