Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

Multiple ABR for the same area.

i have an OSPF network with 3 normal areas and of course a backbone area( area 0)

and one router that resides in area (2) is connected by two links to two ABR routers that connects area (2) to area (0).

i tried to draw a diagram for the topology , R1 is connected to Internet and the Ethernet is in area(0), R2 and R3 are ABRs.

R4 is a remote site and having two links (T1)links to the each for ABR.

also R5 is a remote site and is connected to one of the ABRs by T1.and Link 3 is in area (2) also

note: tha ABRs are on ethernet segment.

when link 2 is not connected, traffic from internet destined to R4 is through link 2 traffic from internet destined toR5 is throught Link3

when i connect link 2 i thought that traffic destined for R4 will be load shared on link1 and link 2 , but this doesn't happen.

what happends is that all traffic destined for R4 comes throught link1 only. and traffic destined to R5 comes throught link1 then link 2 ..and doesn't go throught link 3 at all

can anyone help me in this problem., knowing that link cost are known..

Thanks

Mhaddad

R1

____________|___Ethernet_____________

| |

| |

R2 R3.

, , ,

, , ,

, , ,

, , ,

Link 1 , , Link 2 , Link 3

, , ,

, , ,

, , ,

R4 R5

3 REPLIES

Re: Multiple ABR for the same area.

Are R4 and R5 interconnected on the Ethernetside?

I assumed that they are not.

Looks like you have a static route connected to link1 that takes precedence over the rest. More info will be nescearry though.

Can you upload a sh ip route from R2 and from R4?

New Member

Re: Multiple ABR for the same area.

no ..R4 and R5 are not connected to the ethernet..

and i am not having static routes.., the problem is that i tried to draw a shematic diagram..but when i posted my message..it changed..

so if i can send u the diagram by any other mean..this will make the vision clear for you...if i can send it by mail ..u will see the toplogy well.

and the sho ip route will be too long..

Silver

Re: Multiple ABR for the same area.

It is hard to diagnose with the information given . Do not forget that in OSPF will prefer in interarea router over in interarea route even if the interarea route has a cheaper cost .

186
Views
0
Helpful
3
Replies