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OSPF Path Selection

misaleh
Level 1
Level 1

Below is a summary of a scenario that's happening with me in real life. There are two Internet links, the one connected to ISP A has a 100 Mb/s speed and the one connected to ISP B has a 50 MB/s speed. Router 2 has an OSPF neighborship with Router 0 and Router 1. Router 0 and Router 1 have an OSPF neighborship with Multilayer Switch 0. What's happening now is that when PC1 tries to go to the internet, sometimes it's going through ISP A and sometimes it's going through ISP B. What I'm trying to achieve is that I want anyone in the remote site that's using the internet to use ISP-A and if the connection to ISP A goes down, then they used ISP B. I've tried increasing the cost on Router 2 on the interface connected to ISP B, but nothing happened. Both links to ISPs were being utilized. I've attached a screenshot of the design and also a packet tracer file. Any help would be really appreciated. 

 

 

 

 

 

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16 Replies 16

Of course it will still be utilized. The cost only affects the OSPF learned routes. You still have locally connected routes it can get it that have a lower AD than OSPF. Plus return traffic is still load balancing. You could try increasing the cost of R0s g0/1 interface to say 10. See if that works. And like I said the connected network between R0 and R2 is local so it’ll still use that for traffic to reach it.

 

The design is bad, I recommend you to modify the topology to meet the real scenario.

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