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

  • You must be familiar with basic network interconnections. You'll be ordering and configuring circuits.
  • You must be familiar with the Cloud Interconnect terminology that's described in Key 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:
    • 10G circuits, single mode fiber, 10GBASE-LR (1310 nm), or 100G 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

Elements of Dedicated Interconnect

For definitions of the different elements introduced in the next sections, review the Key terms page.

How does Dedicated Interconnect work?

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

Diagram of a Dedicated Interconnect (click to enlarge)
Dedicated Interconnect (click to enlarge)

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

When you create an interconnect attachment (VLAN), you associate it with a Cloud Router. This Cloud Router creates a BGP session for the interconnect attachment (VLAN) and its corresponding on-premises peer router. Routes that your on-premises router advertises are received by this Cloud Router and 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.

Provisioning overview

Start by ordering an Cloud Interconnect connection so that Google can allocate the necessary resources and send you an LOA-CFA. After you receive the LOA-CFA, you'll need to submit it to your vendor so that they can provision the cross connects between Google's network and your network.

You'll 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 Cloud Interconnect connection.

For information about all the steps required to provision a Dedicated Interconnect, see the Provisioning Overview in the Creating Dedicated Interconnect how-to guide.

Base configuration

For the highest level availability, Google recommends the configuration for 99.99% availability, as shown in the following diagram. Clients in the on-premises network can reach the IP addresses of VM instances in the us-central1 region through at least one of the redundant paths and vice versa. If one path is unavailable, the other paths can continue to serve traffic.

Diagram of redundant interconnects for 99.9% availability (click to enlarge)
Redundant interconnects for 99.99% availability (click to enlarge)


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, one for 99.99% availability and another for 99.9% availability.

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


Dedicated Interconnect availability

A Dedicated Interconnect connection is considered available if you can send and receive packets (ICMP Ping) between a VM instance 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.

Frequently-asked questions

For answers to common questions about Cloud Interconnect architecture and features, see the Cloud Interconnect FAQ.

What's next?