In OSPF interfaces, by putting them in static mode, you will be able to modify the Cost.

In MikroTik RouterOS, modifying the cost of an interface in the OSPF protocol is an important task to influence the route selection process within an OSPF network.

The OSPF cost (also known as “cost”) is used by the OSPF algorithm to determine the shortest path to a destination.

We explain how you can modify this parameter:

Access to the system

To get started, you need to access your MikroTik device. You can do this using WinBox, WebFig, or SSH, depending on your preference and your network configuration.

OSPF Cost Modification

Once inside the system, follow these steps to change the OSPF cost for a specific interface:

1. Navigate to OSPF: Open the OSPF menu by accessing /routing ospf interface. Here you will find all the interfaces that are participating in OSPF.
2. Select the Interface: Choose the interface whose cost you want to modify. You can list the interfaces and their current configurations with the following command:
   
   /routing ospf interface print
   
3. Modify the Cost: Use the following command to modify the cost of a specific interface. Replaces ether1 by the name of the interface you want to configure and 10 for the desired cost value:
   
   /routing ospf interface set [find interface=ether1] cost=10
   

Considerations

• Default Cost: The default cost in OSPF is usually calculated based on the speed of the interface. For example, a faster interface will have a lower cost, making it preferred over slower interfaces.
• Impact of Cost Changes: Changing the cost of an interface can have a significant impact on your OSPF network topology. A lower cost will make the route through that interface more attractive, while a higher cost will make it less desirable.
• Confirmation of Changes: After making changes, it is useful to verify that the modification has taken effect and that the OSPF network topology has been adjusted accordingly. This can be done by checking the current routes in OSPF:
  
  /routing ospf route print
  

Modifying the cost in OSPF within MikroTik's RouterOS is a powerful tool for network administrators looking to optimize network traffic and efficiency. Make sure you fully understand the implications of these changes to avoid unwanted impacts on your network.