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    Express Connect:Create and manage VBRs

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    Express Connect:Create and manage VBRs

    Last Updated:Mar 04, 2026

    A Virtual Border Router (VBR) connects your customer-premises equipment (CPE) to a virtual private cloud (VPC) through an Express Connect circuit. After the circuit is provisioned, create a VBR to forward traffic between the VPC and your customer-premises equipment (CPE).

    Overview

    Each VBR has a route table for managing traffic forwarding and supports the following:

    • Exchanges data packets between a VPC and an on-premises data center as an intermediate router.

    • Sets the port mode of the Express Connect circuit interface to a Layer 3 routed interface or a VLAN-based Layer 3 subinterface. In Layer 3 subinterface mode, the VBR can recognize or attach VLAN tags.

    • Supports dynamic routing with Border Gateway Protocol (BGP).

    Create a VBR

    1. Log on to the Express Connect console.

    2. In the top navigation bar, select the region. In the left-side navigation pane, click Virtual Border Routers (VBRs).

    3. On the Virtual Border Routers (VBRs) page, click Create VBR.

    4. In the Create VBR panel, configure the following parameters, and click OK.

      Note

      If cloud services in your VPC need to access the Alibaba Cloud-side or customer-side IPv4 addresses, add a route entry to the VBR route table. Set the destination to the CIDR block that contains the IPv4 addresses, and set the next hop to the Express Connect circuit. For more information, see Add a custom route entry.

      Parameter

      Description

      Account

      The account where the VBR is created. Current Account is selected by default.

      Name

      Enter a name for the VBR.

      Resource Group

      Select a resource group for the VBR. You can also add the VBR to a resource group after creation. Find the VBR instance and click Add to Resource Group in the Resource Group column.

      Tags

      Select an existing tag key and value, or enter a new key-value pair. Tags help categorize and manage VBR instances.

      Express Connect Circuit

      Select the interface type to bind to the VBR: Hosted or Dedicated. The Express Connect circuit must be provisioned and running. Then, select a circuit from the drop-down list.

      VLAN ID

      Enter a VLAN ID (0 to 2999).

      VBR Bandwidth

      Set the bandwidth for the VBR. For a hosted circuit, this parameter is not required. The VBR inherits its bandwidth.

      Alibaba Cloud Side IPv4 Address

      The IPv4 gateway address for traffic from the VPC to the on-premises data center. This address and the Data Center Side IPv4 Address must be in the same CIDR block.

      Data Center Side IPv4 Address

      The IPv4 gateway address for traffic from the on-premises data center to the VPC.

      IPv4 Subnet Mask

      The subnet mask for the Alibaba Cloud-side and customer-side IPv4 addresses. Because only two IP addresses are required, use a long prefix length.

      Support IPv6

      Disable (default) or Enable. After you enable IPv6, you cannot disable it. When enabled, configure Alibaba Cloud Side IPv6 Address (must be in the same CIDR block as the customer-side IPv6 address), Data Center Side IPv6 Address, and IPv6 Subnet Mask.

    VLAN ID reference

    The VLAN ID determines the port mode of the VBR:

    • 0: The circuit port uses Layer 3 routed interface mode. Each Express Connect circuit corresponds to one VBR. For a dedicated circuit with VLAN ID set to 0, you cannot create subinterfaces with other VLANs for this VBR.

    • 1 to 2999: The circuit port uses VLAN-based Layer 3 subinterfaces. Each VLAN ID corresponds to one VBR. This allows the Express Connect circuit to connect to VPCs under different Alibaba Cloud accounts. VBRs in different VLANs are isolated at Layer 2 and cannot communicate with each other.

    Note

    • For a dedicated circuit, ensure that all Layer 2 and Layer 3 devices between the ISP circuit, the VBR, and your on-premises access device have VLAN trunking enabled for your VLAN tag. If any device does not recognize the VLAN tag or performs VLAN translation, you may experience connectivity issues.

    • For a hosted circuit, the VLAN ID is automatically set and cannot be changed.

    Modify VBR settings

    1. Log on to the Express Connect console.

    2. In the top navigation bar, select the region. In the left-side navigation pane, click Virtual Border Routers (VBRs).

    3. On the Virtual Border Routers (VBRs) page, find the VBR instance and click Actions in the Modify column.

    4. Modify the VBR settings, and click OK.

      Note

      BFD parameters take effect only after you enable BFD. For more information, see Configure and manage BGP.

      Parameter

      Description

      VLAN ID

      Enter a VLAN ID (0 to 2999).

      Alibaba Cloud Side IPv4 Address

      The IPv4 gateway address for traffic from the VPC to the on-premises data center.

      Data Center Side IPv4 Address

      The IPv4 gateway address for traffic from the on-premises data center to the VPC.

      IPv4 Subnet Mask

      The subnet mask for the Alibaba Cloud-side and customer-side IPv4 addresses. Because only two IP addresses are required, use a long prefix length.

      Support IPv6

      Disable (default) or Enable. After you enable IPv6, you cannot disable it. When enabled, configure Alibaba Cloud Side IPv6 Address (must be in the same CIDR block as the customer-side IPv6 address), Data Center Side IPv6 Address, and IPv6 Subnet Mask.

      Support Jumbo Frame

      Enable to set the MTU to 8500. By default, this feature is disabled (MTU = 1500). For more, see Jumbo frame considerations.

      BFD Parameter

      When enabled, a BFD session is established between the Alibaba Cloud side and your on-premises data center. Both ends periodically send BFD packets. If one end does not receive a packet within the detection time, the connection is considered faulty. Configure Submission Interval (200 to 1,000 ms), Reception Interval (200 to 1,000 ms), and Detection Time Multiplier (3 to 10).

    Jumbo frame considerations

    • Jumbo frames can be enabled only after the VBR is bound to an Express Connect Router (ECR).

    • Changing the jumbo frame setting temporarily interrupts the network connection. Ensure that failover measures are in place.

    • The Path MTU Discovery (PMTUD) mechanism determines the effective MTU for a path based on the smallest MTU of any link in that path. If a device on the path does not support jumbo frames, the path MTU is 1500. For example:

      • If two VBRs use Equal-Cost Multi-Path (ECMP) routing and one has jumbo frames disabled, the path MTU is 1500.

      • If two VBRs are configured for active/standby failover and the primary VBR has jumbo frames enabled while the standby VBR does not, the primary path MTU is 8500. If the primary path fails and traffic switches to the standby path, the path MTU becomes 1500.

    • For ECS instance types that support jumbo frames, see Instance types that support jumbo frames.

    Change VBR bandwidth

    You can modify the bandwidth specifications of free VBR instances.

    1. Log on to the Express Connect console.

    2. In the top navigation bar, select the region. In the left-side navigation pane, click Physical Connection.

    3. On the Physical Connection page, click the ID of the Express Connect circuit interface.

    4. On the details page, find the VBR instance and click Actions in the Bandwidth Settings column.

    5. In the Bandwidth Settings panel, select a Bandwidth Cap, and click OK.

    Increase the VBR quota

    After you enable outbound traffic billing, you can create a maximum of five VBRs for each Express Connect circuit per account. To request a quota increase:

    Go to the Quota Center page, search for the ec_quota_same_acount_vbr_per_pconn quota, and click Submit Ticket in the Actions column.

    Delete a VBR

    Before you begin

    Release all associated resources:

    Procedure

    1. Log on to the Express Connect console.

    2. In the top navigation bar, select the region. In the left-side navigation pane, click Virtual Border Routers (VBRs).

    3. On the Virtual Border Routers (VBRs) page, find the VBR instance and click Delete in the Actions column.

      Note

      If the VBR is bound to multiple Express Connect circuit interfaces, click the VBR instance ID. On the Physical Connection Interfaces tab, find the interface and click Unbind in the Actions column.

    4. In the Confirm Deletion dialog box, click OK.

    APIs

    API

    Description

    CreateVirtualBorderRouter

    Creates a VBR instance.

    ModifyVirtualBorderRouterAttribute

    Modifies the configuration of a VBR instance.

    UpdateVirtualBorderBandwidth

    Updates the outbound bandwidth limit of a VBR instance.

    DescribeVirtualBorderRouters

    Queries VBR instances in your account.

    DescribeVirtualBorderRoutersForPhysicalConnection

    Queries VBR instances under a specified Express Connect circuit, including VBRs owned by other accounts.

    DeleteVirtualBorderRouter

    Deletes a VBR instance.

    AttachVbrToVpconn

    Associates a VBR with a hosted connection.

    ListVirtualPhysicalConnections

    Queries information about a hosted connection.