Cloud Interconnect comes up on the Professional Cloud Architect exam in two flavors. The first is recognizing when Interconnect is the right answer over a VPN or public internet path. The second is choosing between Dedicated, Partner, and Cross-Cloud Interconnect for a given scenario. I want to walk through both.
Cloud Interconnect is a separate Google Cloud service that provides a secure, private, high-bandwidth connection between networks. The most common use case is connecting an on-premises data center to a Cloud VPC, but it also extends to other cloud providers.
The defining characteristic is that it bypasses the public internet. That single property drives every reason you would choose it. You get consistent low-latency performance, you get high throughput, and you get a private path that satisfies security and compliance requirements that forbid traversing the public internet.
The use cases that map cleanly to Interconnect on the Professional Cloud Architect exam are:
If a question describes any of those constraints, Interconnect is in the running. If a question describes a small site-to-site link with modest bandwidth and no compliance constraint, Cloud VPN is usually the better answer.
There are three flavors, and each one trades performance against flexibility differently.
Dedicated Interconnect is a direct physical connection between your on-premises data center and Google's network. This is the option you reach for when you need high bandwidth, low latency, and a private path with no third party in the middle. It is also the type most likely to show up on the Professional Cloud Architect exam, so I would not skim past it. Continuous large-scale data transfers and disaster recovery are the canonical scenarios.
Partner Interconnect routes the connection through a supported third-party service provider rather than connecting directly to Google. You pick this when lower bandwidth is acceptable or when geographic flexibility matters, particularly if your data center is not near a Google Cloud edge location. It is the right answer when you need private connectivity but do not need the full performance and control of Dedicated.
Cross-Cloud Interconnect provides a direct connection between Google Cloud and another cloud provider's network. The use case is multicloud organizations that need a secure, high-performance path between clouds without going over the public internet.
Three Dedicated Interconnect patterns come up often enough on the Professional Cloud Architect exam that I want to walk through each one.
The setup is an extremely large volume of data, often financial, that has to move from GCP to an offsite data processing facility. The bandwidth requirement is above 20 Gbps, and public internet transfers are off the table because of throughput limits and security concerns.
The answer is a Cloud VPC plus Dedicated Interconnect. The VPC gives you the isolated, secure network environment inside GCP. Dedicated Interconnect supports speeds above 20 Gbps and gives you the private path. Together they handle the bandwidth and the security requirement in one solution.
You have a 5 TB database in an on-premises data center and you need to keep it synchronized with a Cloud SQL replica. Updates are frequent, replication has to happen in near real time, and the connection must use private IP addresses rather than the public internet.
The answer combines three pieces. A Cloud VPC for the private IP space, Dedicated Interconnect for the bandwidth and low-latency private path, and Datastream for the change data capture and replication itself. Datastream captures changes on the on-prem database and streams them to the Cloud SQL replica, all over private IPs through the Interconnect.
If you see a question that mentions near real-time replication, private IPs, and a multi-terabyte database, this is the pattern.
An organization started with Cloud VPN between on-prem and GCP. That worked for moderate data volumes, but as the business grew, the data volume outgrew what the VPN could deliver. VPN bandwidth is limited, latency is higher because traffic still rides the public internet under encryption, and large dataset transfers or real-time workloads start to suffer.
The answer is to switch to Dedicated Interconnect. It bypasses the public internet, supports up to 100 Gbps, and delivers lower latency. Whenever a question describes a working VPN setup that has run out of headroom because of growing data volume, the migration target is Dedicated Interconnect.
When you see a networking question on the Professional Cloud Architect exam, work through it in this order. First, does the scenario rule out the public internet, either for compliance, security, or performance reasons? If yes, you are in Interconnect territory. Second, what is the bandwidth profile? Tens of Gbps and continuous transfer points to Dedicated. Lower bandwidth or a data center far from a Google edge location points to Partner. A connection between GCP and another cloud points to Cross-Cloud. Third, is there a real-time replication piece? If yes, expect Datastream to appear alongside Interconnect in the correct answer.
My Professional Cloud Architect course covers Cloud Interconnect types and use cases alongside the rest of the networking material.
