Get started Bring yourself up to speed with our introductory content.

How does Azure ExpressRoute make a direct connection to the cloud?

Microsoft offers a way for organizations to connect directly to Azure data centers through one of three connection methods.

Microsoft Azure ExpressRoute allows users to establish a dedicated private connection between the user's data center and an Azure data center. This private connection is facilitated through a connectivity provider, such as AT&T, British Telecom, Verizon, Equinix, Comcast or numerous other major connectivity providers located around the world.

If your current provider supports Azure -- and perhaps even Office 365 -- it should be fairly simple to create a new connection to the closest Azure location. For example, Aryaka Networks can connect to facilities in Amsterdam, Silicon Valley, Singapore and Washington, D.C. The trick here is in the provider's connection to Azure -- not Azure itself.

There are basically three ways to connect a business to Azure using ExpressRoute: cloud exchange, point-to-point and WAN integration. The cloud exchange method is intended to allow colocation providers to connect an outsourced infrastructure to Azure. If the colocation facility has a cloud exchange, it is possible to implement a virtual cross-connect to Azure through the colocation provider.

A point-to-point Ethernet connection provides a dedicated network link from a company's data center to an Azure location. The principal benefit of the link is that it's not shared with the public Internet; it is only used by the business leasing the connection.

Businesses with a wide area network (WAN), such as a college campus or a business with remote or branch offices, can integrate the WAN with Azure using a multiprotocol label switching virtual private network (MPLS VPN). Microsoft calls this an IPVPN, and it can make Azure appear to the WAN as another campus building or branch office.

Connections are also intended to be redundant, so two connections can be established for the same ExpressRoute deployment. Microsoft requires two connections from the connectivity provider's end, though redundant connections from your data center are not needed -- in which case your Azure ExpressRoute will not be redundant.

There are several prerequisites needed to use Azure ExpressRoute. These include a valid Azure account, a separate relationship with a suitable connectivity provider, one of three suitable connectivity models with the provider, and redundant connectivity between the business and provider if redundancy is needed. It may also be necessary to consider IP address, routing, firewall configuration, network address translation and other changes, though these can usually be implemented with assistance from the connectivity provider. Prospective adopters should review Azure ExpressRoute documentation for a detailed examination of specific requirements.

Next Steps

Some of the unexpected charges when using a colo provider

What are some incentives to use Azure ExpressRoute

How to plug virtual servers into the cloud

Dig Deeper on Microsoft Azure cloud services