Routing

Hello,

I hope you are doing well. From what I understand, you have two separate areas, both area 0. The trunk links a019-a020 and b019-b020 are both configured in area 1. Taking the previous into account:

1. This will prevent the router's in one area 0 to see the routes from the other area 0 routers. For example,a019 will only see the routes from b019 and the area 1 link with a020, but it will not install any routes from a020-b020's backbone. So no traffic will be able to flow from the left side of your diagram to the right and vice-versa.

2. The logical thing would be to change the area1 links to area0, but that's obvious and I imagine you have reasons for not doing this, what are this conditions? You could use virtual-links or multiarea adjacency. But the most important questions to really give a good answer are:

- Why are a019-a020 and b019-b020 links in area 1 and for which reasons should they remain that way (if there are any)?

- What is the role of router1, router4, router5 and router6? Are they also part of ospf, if so of which area?

Regards,

Ok. It seems I am not undertanding 100% the topology from that diagram, if you could add the details of interfaces and IP's a little more clearly I would appreciate it.

Another thing I am not understanding is, why don't you configure all the links between a019, a020, b019 and b020 in area 0. Router1/4 are in area1 and are not interconnected between each other directly or through more routers, and Router5/6 are in area2 and are not interconnected between each other directly or through more routers, so because of this there would be no issue doing that.

I am not sure I follow the topology correctly, but I think you might be breaking some basic OSPF area rules.

There can only be one of each area and the area must be fully connected for all devices in the area.  You cannot have two area 0 or two area 1 or two area 2.

Your diagram seems to imply that there are two area 0 that have no connection to each other and operate independantly.

1:I am wondering which issue I should see now(it was confgured wrong I guess).

Your  OSPF route tables will not be complete and some devices won't be able to reach each other as a result.

2: the way to fix it is to create a vlan and assign ip to it, then enable it va the trunk link,right?

Yes, if you add a path and connect the two area 0 then this would work.

3:devices in area1 or area2 are fully connected, right?

I think they are because you say the trunk port betweeen the two sides carry those vlans and I assume those interfaces are placed into the correct area.