Dedicated Interconnect overview

Dedicated Interconnect provides direct physical connections between your on-premises network and Google's network. Dedicated Interconnect enables you to transfer large amounts of data between networks, which can be more cost-effective than purchasing additional bandwidth over the public internet.

Before you use Dedicated Interconnect

Ensure that you meet the following requirements:

  • Be familiar with basic network interconnections so that you can order and configure circuits.
  • Be familiar with Cloud Interconnect terminology.
  • Your network must physically meet Google's network in a colocation facility. You must provide your own routing equipment.
  • In the colocation facility, your on-premises network devices must support the following technical requirements:

    • 10-Gbps circuits, single mode fiber, 10GBASE-LR (1310 nm), or 100-Gbps circuits, single mode fiber, 100GBASE-LR4

    • IPv4 link local addressing

    • LACP, even if you're using a single circuit

    • EBGP-4 with multi-hop

    • 802.1Q VLANs

How does Dedicated Interconnect work?

For Dedicated Interconnect, you provision a Dedicated Interconnect connection between the Google network and your own router in a common location. The following example diagram shows a single Dedicated Interconnect connection between a Virtual Private Cloud (VPC) network and your on-premises network.

A Dedicated Interconnect connection (click to enlarge).
Dedicated Interconnect connection (click to enlarge)

For this basic setup, a Dedicated Interconnect connection is provisioned between the Google network and the on-premises router in a common colocation facility.

When you create a VLAN attachment, you associate it with a Cloud Router. This Cloud Router creates a BGP session for the VLAN attachment and its corresponding on-premises peer router. The Cloud Router receives the routes that your on-premises router advertises. These routes are added as custom dynamic routes in your VPC network. The Cloud Router also advertises routes for Google Cloud resources to the on-premises peer router.


To create and configure a Dedicated Interconnect connection, you start by ordering an Interconnect connection so that Google can allocate the necessary resources and send you a Letter of Authorization and Connecting Facility Assignment (LOA-CFA). After you receive the LOA-CFA, you need to submit it to your vendor so that they can provision the Interconnect connections between Google's network and your network.

You then need to configure and test the connections with Google before you can use them. After they're ready, you can create VLAN attachments to allocate a VLAN on the connection.

For detailed steps to provision a Dedicated Interconnect connection, see the Provisioning overview.

Redundancy and SLA

Depending on your availability needs, you can configure Dedicated Interconnect to support mission-critical services or applications that can tolerate some downtime. To achieve a specific level of reliability, Google has two prescriptive configurations:

For the highest level availability, we recommend the configuration for 99.99% availability as the base configuration, as shown in the following diagram. Clients in the on-premises network can reach the IP addresses of virtual machine (VM) instances in the us-central1 region through at least one of the redundant paths. If one path is unavailable, the other paths can continue to serve traffic.

Redundant Interconnect connections for 99.99% availability (click to enlarge).
Redundant Interconnect connections for 99.99% availability (click to enlarge)

We recommend that you use the 99.99% availability configuration for production-level applications with a low tolerance for downtime. If your applications aren't mission-critical and can tolerate some downtime, you can use the 99.9% availability configuration.

The SLA requires properly configured topologies that are defined by the 99.99% and 99.9% configurations. These configurations ensure availability and provide an SLA.

Balancing egress traffic with redundant Interconnect connections

When you have a redundant topology similar to the 99.99% configuration, there are multiple paths for traffic to traverse from the VPC network to your on-premises network. If the Cloud Routers receive the same announcement with equal cost (same CIDR range and same MED values), Google Cloud uses ECMP to balance the egress traffic across connections.

Creating redundant Interconnect connections with sufficient capacity

The Best practices document describes best practices for creating redundant Interconnect connections that have sufficient capacity in a failover scenario. Following these practices helps ensure that events such as planned maintenance or hardware failures do not cause loss of connectivity.

Dedicated Interconnect availability

A Dedicated Interconnect connection is considered available if you can send and receive packets (ICMP ping) between a VM in a specific Google Cloud region and a correctly configured machine in your on-premises network. You should be able to send and receive packets through at least one of your redundant connections.

Restricting Dedicated Interconnect usage

By default, any VPC network can use Cloud Interconnect. To control which VPC networks can use Cloud Interconnect, you can set an organization policy. For more information, see Restricting Cloud Interconnect usage.

What's next?