03-20-2010 03:20 PM - edited 03-06-2019 10:14 AM
Hi Friends;
Any one has idea what's going on in the belwo
R1
| (BGP)
|------------------------|
R3---------------------R2
| OSPF Area1 |
R5-------------------- R4
OSPF Area 0
-R1 is running BGP with R2 and R3
-R2 is primary router So it's redistribute BGP into OSPF metric 100 type E1
-R3 is Secondry router So it's redistribute BGP into OSPF metric 200 type E1
The problem is R5 always using R3 to reach R1 however the metric os this path is higher than the one coming from R4, Any Idea, Thanks
Best Regards;
M.Kamar
Solved! Go to Solution.
03-21-2010 05:17 AM
No, you cann't disable it; you can create a tunnel and put the tunnel in area 1, and change the tunnel cost to make it the prefer path.
03-20-2010 07:08 PM
Hi M.Kamar,
Because intro-area route always prefer over inter-area route.
HTH,
Lei Tian
03-21-2010 12:11 AM
Thanks Lei;
Is there a way to disable this feature and make and let the router consider the cost 1st?
Best regards;
Mohamed Kamar
03-21-2010 05:17 AM
No, you cann't disable it; you can create a tunnel and put the tunnel in area 1, and change the tunnel cost to make it the prefer path.
03-21-2010 05:19 PM
Hi Letian;
Ops, This is a wonderful idea, I think i'll go it
Best Regards;
Mohamed Kamar
03-21-2010 06:03 PM
Mr. Kamar:
Can you please show the complete route table entry on R5 for the network you are trying to reach?
Im not sure I understand which is the intra-area and which is the inter-area route...
The BGP routes that R5 receives will be OSPF external type 1 routes (O E1).
R5 and R4 are both ABRs, arent they?
[EDIT] And R1, R2 and R3 have all OSPF interfaces in Area 1, while R4 and R5 have one interface in Area 1 and the other in Area 0. [EDIT]
Please correct me if I am misunderstanding something.
Thanks
03-23-2010 01:56 AM
Hi ex-engineer ;
I took 3 routes from R5 for you, fa 1/0 is the link to R3, note how much the cost is, and the routes are preffered, note also when i shut down this link the routes came from R4 fa 0/0, you will note also that all these routes are External but in the 1st case before shut down it came from Intra-area and in the 2nd case after shut down it came from Inter-Area
That's way we conclude that there is no way to change this OSPF behavior (Intra better than inter) and the work around is either put area 1 link between R4 and R5 or create a tunnel between them to force the traffic to take this path, Thanks
O E1 10.0.0.0/24 [110/1110] via 10.201.0.68, 00:02:13, FastEthernet1/0
O E1 10.0.0.0/23 [110/1200] via 10.201.0.68, 00:02:08, FastEthernet1/0
O E1 10.0.1.0/24 [110/1110] via 10.201.0.68, 00:02:13, FastEthernet1/0
R5(config)#int fas 1/0
R5(config-if)#shutdown
O E1 10.0.0.0/24 [110/111] via 10.201.0.25, 00:00:55, FastEthernet0/0
O E1 10.0.0.0/23 [110/221] via 10.201.0.25, 00:00:55, FastEthernet0/0
O E1 10.0.1.0/24 [110/111] via 10.201.0.25, 00:00:55, FastEthernet0/0
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