Arc uses the TM1 REST API to connect to a TM1 instance. You can either connect to a TM1 instance using the adminhost REST API port or using the TM1 REST API port of a specific TM1 instance.
Connect to all TM1 instances from an adminhost
In the settings.yml file if you define an Adminhost with the Admin host REST API port (5898 is the default one), Arc will be able to connect to all TM1 instances on this admin host:
To connect to multiple admin hosts, just follow the steps in the following article:
Connect to one TM1 instance via REST API
Another way to connect to a TM1 instance is to use the REST API port of a TM1 instance (HttpPortNumber in tm1s.cfg). This will be beneficial if you are connecting to a cloud environment and only the REST API port has been opened.
More details in the following article: