ospf help

[ROH]

R5                                                    R1

|   (R5 and R4 area 2)                |               |    

|   (R4 and R3 area 1)            |     (area 0)     |

R4- - ---- ------------R3-----------------R2

I initiated OSPF with process ID 1 on all routers. Later, I created a virtual interface on R5 to establish a connection with the backbone area, and everyone could ping each other. Subsequently, I decided to experiment and removed OSPF process 1 on R5 and R4, replacing it with OSPF process 2. After that, on R3, I defined processes 1 and 2, redistributed between them, and except for R5, all routers could communicate with each other However, I couldn't connect R5 to the backbone area. I would be happy if anyone helps . Regards.

[MHM Cisco World]

Where you config redistrubte in R4?

MHM

[ROH]

I couldn't configure the virtual connection with redistribution.

[MHM Cisco World · Accepted solution]

This not work

Virtual work if all area in same process in which area 2 use virtual link to connect to backbone area0 through area 1

Here 

Process id 2 have two area without backbone area 0.

And virtual link not work between area of process and backbone area0 of other process.

There is trick but use it in lab only not in real network' trick is add lo in R2 and use it under opsf with area 0

MHM

[ROH]

ım grateful 

[ROH]

Can you explain the logic? Meanwhile, networks are entered into the routing table but not pinged.

[MHM Cisco World]

Sorry what is not ping?  Can you more elaborate 

MHM

[ROH]

R1

If I understand correctly from what you said, I created loopback interfaces on R2 and assigned an IP address from area 0. Then, R1 learned all the networks, but it couldn't ping the area 0 (10.0.34.0) network. As far as I can tell, I inadvertently created a virtual backbone area.

[ROH]

10.0.34.5 is loopback

[MHM Cisco World]

I inadvertently created a virtual backbone area.

You are correct.

For ping I will check in my lab and update you.

As I mention before it trick and not use in real network and I think you hit it limitations.

Let me see that 

MHM

[ROH]

Thank you very much for your help, I will be waiting

[balaji.bandi]

Look at the OSPF design guide :

https://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/7039-1.html

if you have still issue - post run from all the routers

[Gopinath_Pigili]

If you goal is connecting R5 to backbone area (Area 0)....You don't need to configure redistribution....You will be needed configure virtual-link on ABR's R4 and R3

According to ospf design requirements...Each non-backbone area must be directly connected to Area 0 which is Backbone Area. Some poorly designed ospf networks....if any non-backbone area is not connected directly to Backbone Area (Area 0)....You can establish connection from non-backbone area(Area 2) to Area 0 using virtual-links.

Virtual-links should be configure only on ABR's both R4 and R3 

R4(config-router)# area 1 virtual-link x.x.x.x
R3(config-router)# area 1 virtual-link x.x.x.x

Here x.x.x.x is remote ABR router-id(RID).

Best regards
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