This topic describes the terms commonly used in Express Connect.
The following figure shows the networking architecture of using physical connections to connect on-premises data centers to Alibaba Cloud.
The following table lists basic terms of physical connections.
|Express Connect||An Alibaba Cloud service that helps you build private network communication channels between VPCs or between VPCs and on-premises data centers. It provides features that increase network topology flexibility and enhance cross-network communication quality and security.|
|Virtual Private Cloud (VPC)||A custom private network created in Alibaba Cloud. VPCs are logically isolated from each other. You can create and manage your cloud instances, such as Elastic Compute Service (ECS) instances, Server Load Balancer (SLB) instances, and ApsaraDB for RDS (RDS) instances in your VPC.|
|Virtual Border Router (VBR)||A router between your Customer-Premises Equipment (CPE) and the VPC. It serves as a bridge for data exchange between your on-premises data center and the VPC.|
|VRouter||A hub that connects all VSwitches in a VPC and serves as a gateway to connect the VPC with other networks.|
|Cloud Enterprise Network (CEN)||An Alibaba Cloud service that helps you build private network communication channels
between VPCs or between VPCs and on-premises data centers. It features automatic route
distribution and learning, faster convergence, and improved quality and security of
cross-network communication. By using CEN, you can connect all your network resources
and build a network and communication capabilities at an enterprise scale.
Also, you do not need to set routes for VPCs that are connected through CEN, which simplifies network operation and maintenance. For more information, see What is Cloud Enterprise Network?
|Physical connection interface||A physical interface through which a leased physical line accesses an Alibaba Cloud access point.|
|Access point||A geographical location where the leased line is connected to Alibaba Cloud. Each access point has two access devices. Each region has one or more access points, any of which can be used to access Alibaba Cloud VPCs.|
|Border Gateway Protocol (BGP)||A routing protocol designed to exchange routing and reachability information among gateways and autonomous systems.|
|Equal-cost multi-path (ECMP) link aggregation||A method that is used to increase the bandwidth of physical connections through ECMP routing, specifically, by connecting multiple leased lines to the same device and associating the multiple physical connections with the same VBR.|
|Exclusive physical connection||A physical connection solution where a dedicated physical port of Alibaba Cloud and a dedicated leased line of a third-party service provider are used to connect an on-premises data center to an Alibaba Cloud access point.|
|Shared physical connection||A physical connection solution where customers connect an on-premises data center to Alibaba Cloud through a leased line and the network of a third-party service provider. In this solution, the third-party service provider establishes the link between their access point and an Alibaba Cloud access point that can be shared by multiple customers.|