The Tenant Portal is a Data Center Operation for Colo web application in which colocators can share customer specific DCIM information with their customers, the tenants.
As colocator, you can configure the application to share just what is relevant to each of your customers. Nothing more, nothing less.
You can also keep the high-level overview of your data center and use the web client for online lightweight access to some of the features in the DCO model without having to launch the desktop client.
As tenant, you will be granted access to the part of the colocator's data center infrastructure relevant to you. You'll be able to see your inventory and, depending on your configuration, additional features such as edit your inventory, monitor space, power, and cooling thresholds.