How Is the Network Speed of a VPN Connection Tested?

Test environment: A VPN connection has been created. ECSs have been created on the local subnets of VPCs at the two ends of the VPN connection. The ECSs can ping each other.

When the bandwidth of a purchased VPN gateway is 200 Mbit/s:

1. When the ECSs at the two ends of the VPN connection run Windows, iPerf3 and FileZilla (a free FTP application for file upload and download) are used to test the network speed. The test result is 180 Mbit/s, meeting requirements.
   

   The TCP-based FTP protocol has a congestion control mechanism, and the IPsec protocol adds new headers to original packets. As such, it is normal in the industry, to have a network speed deviation of about 10%.

   Figure 1 shows the result of testing the 200 Mbit/s bandwidth on the iPerf3 client.

   Figure 1 Test result for 200 Mbit/s bandwidth (iPerf3 client)
   

   Figure 2 shows the result of testing the 200 Mbit/s bandwidth on the iPerf3 server.

   Figure 2 Test result for 200 Mbit/s bandwidth (iPerf3 server)
   
2. When the ECSs at the two ends of the VPN connection run CentOS 7, iPerf3 is used to test the network speed. The test result is 180 Mbit/s, meeting requirements.
3. When the ECS functioning as a server runs CentOS 7 and the ECS functioning as a client runs Windows, iPerf3 and FileZilla are used to test the network speed. The test result is 20 Mbit/s, failing to meet requirements.

   This is because TCP implementations on Windows and Linux are different.

   Figure 3 shows the result of using iPerf3 to test the network speed between two ECSs running different operating systems.

   Figure 3 Test result on iPerf3
   

When the bandwidth of a purchased VPN gateway is 1000 Mbit/s:

Some regions support only 300 Mbit/s bandwidth by default. If higher bandwidth is required, apply for 300 Mbit/s bandwidth and then submit a service ticket for capacity expansion.

The VPN gateway bandwidth is shared by all of its VPN connections. To fully use the large bandwidth of 1000 Mbit/s, deploy multiple ECSs with high specifications as the forwarding performance of a single ECS is limited. ECSs with their NICs supporting the bandwidth of 2 Gbit/s or higher are recommended.

Conclusions: Based on the preceding test results, bandwidths of VPN gateways meet requirements. To fully use your purchased bandwidth, you are advised to use servers running the same operating system and using NICs meeting certain requirements at the two ends of a VPN connection.