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Cloud Enterprise Network:Transit routers

Last Updated:Jul 10, 2026

A transit router is a core forwarding element that routes traffic within and across regions. You must create a transit router before you can connect network instances. Each Cloud Enterprise Network (CEN) instance supports one transit router per region.

Background information

You can create a transit router in either of the following ways:

  • Automatic creation

    When you connect the first network instance (VPC, ECR, VBR, or CCN) in a region, the system automatically creates a transit router in that region. For more information about connecting these instances, see the following topics:

  • Manual creation (recommended)

    Manually create a transit router by following the steps in this topic. For more information, see Create a transit router.

    Note

    Before you create a VPN attachment, you must manually create a transit router.

Create a transit router

  1. Log on to the CEN console.

  2. On the CEN Instance page, click the ID of the CEN instance that you want to manage.

  3. On the Basic Settings > Transit Router tab, click Create Transit Router.

  4. In the Create Transit Router dialog box, set the parameters for the transit router and click OK.

    Parameter

    Description

    Region

    Select the region where you want to create the transit router.

    Edition

    The edition of the transit router.

    The edition is automatically determined by the selected region. For more information about the regions that support Basic Edition and Enterprise Edition transit routers, see Transit router editions.

    Enable Multicast

    Enables multicast for the transit router. This feature is disabled by default.

    Note

    Only Enterprise Edition transit routers in specific regions support multicast. For more information, see Multicast.

    Name

    Enter a name for the transit router.

    Description

    Enter a description for the transit router.

    Tag

    Add tags to the transit router. This setting applies only to Enterprise Edition transit routers.

    • Tag key: cannot be an empty string. The key can be up to 64 characters in length and cannot start with aliyun or acs:. It cannot contain http:// or https://.

    • Tag value: can be an empty string. The value can be up to 128 characters in length and cannot start with aliyun or acs:. It cannot contain http:// or https://.

    You can add multiple tags to an Enterprise Edition transit router. For more information about tags, see Tags.

    Transit Router CIDR

    The CIDR block for the transit router. This setting applies only to Enterprise Edition transit routers.

    This CIDR block, which functions similarly to that of a loopback interface, is used by the transit router to allocate IP addresses for IPsec VPN connections . For more information, see Transit router CIDR.

View transit router edition

You can view the edition of an existing transit router in the console.

  1. Log on to the CEN console.

  2. On the CEN Instance page, click the ID of the CEN instance that you want to manage.

  3. You can view the edition of a transit router in either of the following ways:

    • On the Basic Settings > Transit Router tab, find the target transit router and view its edition in the Edition column.

    • On the Basic Settings > Transit Router tab, click the ID of the target transit router. On the details page of the transit router, click the Basic Settings tab. On the Basic Settings tab, view the Version.

Delete a transit router

You can delete transit routers that you no longer need. Before you delete a transit router, make sure that the following prerequisites are met:

  1. Log on to the CEN console.

  2. On the CEN Instance page, click the ID of the CEN instance that you want to manage.

  3. On the Basic Settings > Transit Router tab, find the target transit router and click Delete in the Actions column.

  4. In the Delete Transit Router dialog box, confirm the instance ID and click OK.

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