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Cloud Enterprise Network:Diagnose a transit router instance

Last Updated:Aug 06, 2026

Cloud Enterprise Network (CEN) integrates with Network Intelligence Service (NIS), allowing you to diagnose your transit router instances. This feature automatically identifies network issues, explains the root causes, and provides actionable recommendations. Use this feature to troubleshoot problems without manually inspecting your network configurations.

Limitations

This feature supports only Enterprise Edition transit router instances.

Transit router diagnostic items

The following table lists the diagnostic items for transit router instances.

Category

Item

Description

Configuration

Cross-region throttling check

Checks whether a bandwidth limit is configured for the inter-region connections of the transit router.

Route learning check

Checks whether route learning exists between the network instance connections and the route table of the transit router.

If route learning is not required for a network instance connection, ensure that a static route to the network instance exists in the route table of the transit router. Otherwise, the transit router cannot forward traffic to the network instance.

For more information about route learning, see Route learning.

Associated forwarding check

Checks whether an associated forwarding relationship exists between the network instance connections and the route table of the transit router.

For more information about associated forwarding, see Associated forwarding.

Network ACL configuration check

Checks whether the network ACL allows traffic from the CIDR block of the vSwitch that connects the VPC to the transit router.

For more information about network ACLs, see Network ACLs.

Automatic route advertisement check

Checks whether automatic route advertisement is enabled for VBR connections and inter-region connections.

Enable automatic route advertisement for VBR and inter-region connections to allow VBR instances and transit routers to automatically learn routes from each other.

Quota

Route usage check

Checks whether the number of routes in the route table of the transit router has reached 80% of the route quota.

Cross-region throttling check (QoS queue)

Checks whether the bandwidth utilization of each QoS queue for the inter-region connection has reached 80%.

Cross-region throttling check (connection)

Checks whether the bandwidth utilization of the inter-region connection has reached 80%.

Inter-region connection packet loss check

Checks whether the inter-region connection experienced packet loss due to throttling in the last 15 minutes.

QoS queue packet loss check

Checks whether the QoS queues of the inter-region connection experienced packet loss due to throttling in the last 15 minutes.

Payment

Overdue payment alert

Checks whether the bandwidth plan associated with the CEN instance has an overdue payment.

Expiring bandwidth plan alert

Checks whether the bandwidth plan associated with the CEN instance will expire within 7 days.

Route

Route conflict check

Checks for route conflicts among network instances connected to the transit router.

VPC routes check

Checks whether the destination CIDR blocks of all routes that point to the transit router in the VPC's route table cover all destination CIDR blocks in the transit router's route table. This applies to the route table associated with the VPC connection.

Run a diagnostic

  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 transit router instance in the target region and click Diagnose in the Instance Diagnostics column.

  4. In the Instance Diagnostics panel, view the diagnostic details.

    Note
    • If you have not activated NIS, select Terms of Service for Standard Edition NIS and click Activate NIS free of charge to diagnose instances..

    • When you run a diagnostic for the first time, the system automatically creates a service-linked role named AliyunServiceRoleForNis. For more information about this role, see Service-linked roles.

    Callout

    Description

    This section displays any detected issues. You can view the description of each issue, the affected resources, and the recommended solution.

    In the Diagnostic Items section, select Show All Diagnostic Items to view the results for all diagnostic checks for the transit router.

    At the top of the Instance Diagnostics panel, click View Diagnostic History in NIS Console. This action redirects you to the Overview page of the NIS console, where you can view historical diagnostic reports for the transit router. For more information, see Overview.

References

To learn more about the Instance Diagnostics feature in NIS, see Use instance diagnostics.