Understanding ExpressRoute components

The purpose of ExpressRoute is to connect a remote customer network to a customer’s Azure VNet or a customer’s Microsoft cloud service tenant. But to understand how ExpressRoute works, we need to understand the components that an ExpressRoute connection is made of. Take a look at the following diagram:

Figure 6.3 – ExpressRoute key network components

Figure 6.3 illustrates the logical connection of a customer network to the Microsoft network using ExpressRoute. The numbers in the diagram represent important network points, listed as follows:

1. On-premises devices: Devices located physically within an organization’s premises.
2. Customer edge (CE) routers: Routers used by customers to connect to their ExpressRoute partner network.
3. Provider edge devices facing CE routers: These are routers/switches used by ExpressRoute service providers (SPs) to connect to CE routers.
4. Partner...