ExpessRoute will soon support Office 365. Read the announcement.
Azure ExpressRoute lets you create private connections between Azure datacenters and infrastructure that’s on your premises or in a colocation environment. ExpressRoute connections don't go over the public Internet and offer more reliability, faster speeds, lower latencies, and higher security than typical Internet connections. In some cases, using ExpressRoute connections to transfer data between on-premises systems and Azure can also yield significant cost benefits.
With ExpressRoute, you can establish connections to Azure at an ExpressRoute location, such as an Exchange provider facility, or directly connect to Azure from your existing WAN network, such as a multi-protocol label switching (MPLS) VPN, provided by a network service provider.
ExpressRoute gives you a fast and reliable connection to Azure, making it suitable for scenarios like periodic data migration, replication for business continuity, disaster recovery, and other high-availability strategies. It can also be a cost-effective option for transferring large amounts of data, such as datasets for high-performance computing applications, or moving large virtual machines between your Dev/Test environment in Azure and your on-premises production environment.
ExpressRoute lets you securely add compute and storage capacity to your existing datacenter. With high throughput and fast latencies, Azure will feel like a natural extension to your datacenter, so you enjoy the scale and economics of the public cloud without having to compromise on network performance.
With predictable, reliable and high-throughput connections offered by ExpressRoute, you can build applications that span on-premises infrastructure and Azure without compromising security or performance. For example, you can have a corporate intranet application running in Azure that authenticates users using an on-premises Active Directory service, and serve all corporate users without traffic ever routing through the public Internet.