Alcatel Unleashed

Hi all,
Can you please help me to understand what is exacly the method that is used by 7750 OSPF configuration to choose one route When we have two routes with the same metric. In my tests with ecmp = 2 the two routes are in the route table, but when i change the ecmp to its default value (=1) only one route is installed but i don't understand how the equipament choose it. in ALU doc they say that the lowest next-hop ip address is the method to prefer the route, but in my configuration it doesn't happened.
Thx in advance
Regards.
/mserrao

Hi,
As you rightly said, OSPF will installed only the best route (prefix) in the routing table, of course you can see the rest in the database.
ECMP (Equal Cost Multi Path), when implemented allows OSPF to install up to four paths with equal cost (metrics) in the OSPF routing table intead of the default behavior of one route.
So in your own case, it makes a lot of sense that when implemented you can see two paths to same destination, when you remove, OSPF revert back to installing only the best route in the table.

I hope it make sense?.
Eagleman

I think he was asking about which of two OSPF routes is chosen if ECMP is off.

mpmserrao, maybe if you post an example of where it's not working as expected?

The output of show router ospf routes <ip-prefix> detail

[duplicate post deleted]