Run a one-click diagnostic scan on a virtual border router (VBR) to check its health, configuration, quota usage, and billing status — and get actionable remediation steps for any anomalies found. Diagnostic results integrate with Network Intelligence Service (NIS), where you can also view historical diagnostic records.
Prerequisites
Before you begin, ensure that you have:
NIS activated. To activate NIS, go to the NIS service activation page.
The AliyunServiceRoleForNis service-linked role available. This role is created automatically the first time you run a diagnostic. For details, see Service-linked roles.
A VBR created. For details, see Create and manage a VBR.
Run a VBR diagnostic
Log on to the Express Connect console.
In the top navigation bar, select a region. In the left-side navigation pane, click Virtual Border Routers (VBRs).
On the Virtual Border Routers (VBRs) page, find the VBR you want to diagnose and click Diagnose in the Instance Diagnostics column.
In the Instance Diagnostics panel, review the progress, summary, and details of the diagnostic task.
Anomalies detected are listed in the panel with their severity level.
To see the full list of checked items, select Show All Diagnostic Items in the Diagnostic Items section.
To view additional diagnostic information and historical records, click Go to the NIS console to view diagnostic records.
After reviewing the results, click Close.
Diagnostic items
The following tables list all diagnostic items, grouped by category. Each item describes what is checked.
Severity levels use the following color coding: Blue = Critical, Red = Major, Orange = Minor, Yellow = Info, Green = Passed.
Health check diagnostics
Checks whether health monitoring is configured and functioning correctly for your VBR connections.
| Diagnostic item | What is checked |
|---|---|
| Health Check Configuration | Whether health checks are configured for the Cloud Enterprise Network (CEN) or VBR-to-virtual private cloud (VPC) connection |
| Loss of Health Check Probes | Whether packet loss is occurring during health checks for the CEN or VBR-to-VPC connection |
Configuration diagnostics
Checks the core connectivity configuration of the VBR and its physical port.
| Diagnostic item | What is checked |
|---|---|
| Physical Port Status | Whether the physical port connected to the Express Connect circuit is up |
| Reachability between Client IP and VBR | Whether the on-premises IP address can ping the Alibaba Cloud-side IP address of the VBR |
| BGP Connection Status | Whether the BGP neighbor status on the VBR is Established |
| VBR Connection Redundancy | Whether redundant connections are configured for the transit router-to-VBR and VPC-to-VBR paths |
| Optical Transceiver of Physical Port | Whether the optical transceiver of the physical port is functioning within expected parameters |
Quota limit diagnostics
Checks whether the VBR is approaching or has exceeded resource limits that could affect traffic forwarding.
| Diagnostic item | What is checked |
|---|---|
| BGP Route Entries | Whether the number of BGP route entries has exceeded the upper limit on the VBR |
| VBR Packet Loss | Whether packet loss is occurring because the VBR is overwhelmed by traffic |
Cost diagnostics
Checks whether the VBR or its associated resources have overdue payments that could affect service availability.
| Diagnostic item | What is checked |
|---|---|
| VBR Overdue Check | Whether the VBR has overdue payments |
| VBR-to-VPC Connection Overdue Check | Whether the VBR-to-VPC connection has overdue payments |
| Check for Overdue Payment of Physical Port | Whether the physical port associated with the VBR has overdue payments |
What's next
For advanced diagnostic workflows and historical record analysis, see Work with instance diagnostics in the NIS documentation.