Google Interconnect is a solution where a network port on Google’s network is made available for customers to connect to. In most cases, the port will be in a Point of Presence (PoP) datacenter facility where the end customer will order an MPLS WAN connection from their preferred carrier, who will assist with cross-connecting it to the port provided by Google. Other configurations are possible, such as a Hosted Connection (a VLAN on a shared port) a Hosted VIF (a single virtual interface on a shared connection), and in some cases customers may collocate space in the PoP and run the cross-connect directly from their own equipment.  All of these options provide different features, bandwidth, and cost models.

Dedicated ports provide the most capability and highest bandwidth, Ideas to consider:

In order to minimize latency, select an Google Cloud point-of-presence that your WAN provider can support, and is as close as possible to the sites that will be communicating with the Private Clouds.

Deploy multiple Google Interconnect circuits to different points-of-presence for redundancy, that terminate in the same Google Cloud account so that Google knows they are for redundancy and will provision them on independent paths. Ensure that they have fully independent paths to the enterprise network.

If multiple regions are being used for Private Clouds and latency tolerance is acceptable, consider deploying Google Interconnects to different regions,  to provide redundancy against wider-area events while simultaneously providing connectivity to multiple regions.

Use BGP secrets on all BGP sessions to avoid route hijacking.