After you establish a physical connection, you need to create a Virtual Border Router (VBR), which works as a forwarding bridge for data from the VPC to your on-premises data center.

Background information

VBR is a router between the VPC and the Custom-Premises Equipment (CPE) in your on-premises data center. The VBR has a route table. You can configure route entries in the route table to manage traffic forwarding in the VBR. VBR provides the following functions:
  • Exchanges data packets as an intermediate router between the VPC and the on-premises data center.
  • Decides the port mode of the physical connection: Layer-3 route interface mode or VLAN-based Layer-3 sub-interface mode.
  • Attaches or identifies VLAN tags in Layer-3 sub-interface mode.
  • Supports BGP dynamic routing.

Procedure

  1. Log on to the Express Connect console.
  2. In the left-side navigation pane, choose Physical Connections > Virtual Border Routers (VBRs).
  3. Click Create VBR.
  4. Configure the VBR, and then click OK.
    Configuration Description
    Account Select whether to create a VBR for the current account or for a different account.
    Account

    If you create a VBR for a different account, enter the ID of the account.

    VLAN ID Enter the VLAN ID of the VBR. Value range: 0 to 2999.
    • If the VLAN ID is 0, it indicates that the switch port of the VBR uses Layer-3 route interface mode instead of VLAN mode. In Layer-3 route interface mode, each physical connection corresponds to a VBR.
    • If the VLAN ID is a value from 1 to 2999, it indicates that the switch port of the VBR uses VLAN-based Layer-3 sub-interface mode. In Layer-3 sub-interface mode, each VLAN ID corresponds to a VBR. In this mode, the physical connection of the VBR can connect the VPCs under multiple accounts. The VBRs of different VLANs are isolated from one another by the Layer-2 network.

    For example, a company has multiple subdivisions or subsidiaries. Each has an independent Alibaba Cloud account, and each account has an independent VPC. If the company applies for a physical connection, it needs to plan a VLAN ID for each subdivision or subsidiary. When creating router interfaces, the company uses VLAN IDs to identify the subsidiaries or subdivisions that use the physical connection, isolating them from each other by using the Layer-2 network.

    Gateway IP Address on Alibaba Cloud Side Enter the IP address of the gateway from the VPC to your on-premises data center.
    Gateway IP Address on Customer Side Enter the IP address of the gateway from your on-premises data center to the VPC.
    Subnet Mask Enter the subnet mask of the gateway IP address on the Alibaba Cloud side and the gateway IP address on the customer side. Only two IP addresses are required. Therefore, you can enter a longer subnet mask.