Performance and connectivity considerations

When you deploy and operate an application or workload on Microsoft Azure operated by 21Vianet (Azure China), you should test the performance and network.

In addition, if your Azure application provides services to users outside of China, consider the following:

  • For users in China, host workloads in Azure China.
  • For users outside of China, deploy workloads to the closest Azure region.

Performance considerations

To fine-tune and optimize your Azure application, conduct performance tests and consider the following recommendations:

  • Conduct your performance testing in China Standard Time, instead of your own time zone.
  • Conduct testing in mainland China, to better reflect the response times and the real user experience.
  • Test during the internet rush hours to measure the performance of your application under high workloads.

Network latency in China

The network latency between China and the rest of the world is inevitable, because of the intermediary technologies that regulate cross-border internet traffic. Website users and administrators might experience slow performance. The following tips might help:

  • For websites with streaming media and other rich media content, the Azure Content Delivery Network (CDN) can help improve responsiveness. Under Chinese law, using the CDN service in China might also subject an offshore website to ICP filing. Don't use a global CDN service that doesn't have a point of presence (PoP) inside mainland China.
  • For the best user experience, host a website in China to serve users in China.
  • For website administrators outside of China, use Secure Shell (SSH) to connect to your remote server for a faster network connection to Microsoft Azure China. For example, use SSH to access a local Azure virtual machine, and from there, use SSH to connect to an Azure China virtual machine.

Global connectivity and interoperability

A hybrid cloud can extend your applications or workloads in Azure China, and provide global connectivity and interoperability. The following connections are supported:

  • Use a virtual private network (VPN) or Azure ExpressRoute to create a direct network connection between Azure and your on-premises private cloud or back-end systems within China.
  • Set up a site-to-site VPN to connect an Azure site in China to your on-premises location outside of China. ExpressRoute is not supported for direct network connectivity to an external (outside of China) site. Even Azure global is considered external.


You need approval by the Ministry of Industry and Information Technology (MIIT) of the Chinese government to set up a VPN or ExpressRoute connection between your services hosted on Azure, your ICP-registered hosting location, and an outside location. You must register, report, and obtain for approval from the MIIT. Contact support for help in the approval process.

For a VPN setup, apply for an exception through Azure support, and provide the following information:

  • Overseas IP address for the overseas VPN endpoint
  • VPN protocol and ports
  • Location of overseas IP
  • Owner of overseas IP
  • Relationship between the overseas IP owner and the Azure customer

Need support? Find details in Support for Azure China.