Why Would an Organisation Need ExpressRoute?
When organisations first move workloads to Azure, connectivity is usually not a complex discussion.
Applications are accessed over the public internet, often protected by encryption and, in some cases, a VPN.
For many businesses, this approach works perfectly well in the early stages of cloud adoption.
However, as reliance on Azure increases, the limitations of internet-based connectivity start to surface.
This is the point where organisations begin to ask a more serious question:
Is the public internet good enough for the way we now depend on Azure?
Azure ExpressRoute exists to answer that question
At its core, ExpressRoute provides a private, dedicated connection between an organisation’s on-premises network and Microsoft’s cloud.
Unlike VPN or internet-based access, traffic over ExpressRoute does not traverse the public internet.
Instead, it uses a private path into Microsoft’s network, offering a different class of connectivity altogether.
The primary reason organisations consider ExpressRoute is predictability. Public internet traffic is shared and inherently variable.
Latency can fluctuate, throughput can drop during peak periods, and routing paths can change without notice.
For non-critical workloads, this variability is often acceptable. For business-critical systems, it is not.
Organisations running large data transfers, latency-sensitive applications, or systems that require consistent performance need connectivity they can rely on.
ExpressRoute removes much of the uncertainty associated with internet routing and provides predictable performance that can be planned and scaled.
Reliability is another major factor. When Azure becomes tightly integrated into day-to-day operations, connectivity issues can have real financial and operational consequences.
ExpressRoute is designed for these scenarios, offering enterprise-grade connectivity backed by service level agreements.
This makes it suitable for workloads where downtime, packet loss, or instability would directly impact the business.
Security and compliance requirements also play a significant role
Many organisations operate in regulated industries where policies restrict how data can travel across networks.
Even when encrypted, sending sensitive traffic across the public internet may not be acceptable from a governance or compliance perspective.
ExpressRoute allows organisations to keep traffic off the public internet entirely, providing greater control over network paths and meeting stricter security requirements.
It’s important to understand that ExpressRoute is not intended to replace all other connectivity options.
Microsoft positions it as a premium solution, designed for specific use cases rather than as a default choice.
For smaller workloads, lower traffic volumes, or non-critical systems, VPN connectivity may be simpler and more cost-effective.
ExpressRoute becomes relevant only when the business requirements demand a higher level of performance, reliability, and control.
In simple terms, organisations consider ExpressRoute when they reach a point where Azure is no longer just “another system on the internet,” but a core part of their infrastructure that requires enterprise-grade connectivity.
Where This Fits in the Design Journey
Understanding why ExpressRoute is needed is the true starting point of the design process.
Only once this justification is clear does it make sense to move on to architectural decisions.
The next step is deciding how the organisation should connect to Microsoft’s network, which leads directly into the choice between ExpressRoute Direct and ExpressRoute using a service provider.