Help Center/ Virtual Private Cloud/ Help Panel/ Virtual Private Cloud/ Connecting VPCs to On-Premises Data Centers
Updated on 2025-08-06 GMT+08:00
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Connecting VPCs to On-Premises Data Centers

If you have an on-premises data center and not all your workloads can be migrated to the cloud, you can use the network services described in Table 1 to connect your on-premises data center to the VPCs.

Table 1 Network services that can connect VPCs to on-premises data centers

Network Service

Function

Highlights

VPN

VPN provides an encrypted, Internet-based channel that connects an on-premises data center and the cloud.
  • Low costs
  • Simple configuration
  • Immediate use
  • The network quality depends on the Internet.

Direct Connect

Direct Connect establishes a dedicated network connection between an on-premises data center and the cloud.
  • Dedicated connections with high security
  • Low latency and high speed

VPC Peering

With VPC Peering, you can peer two VPCs in the same region, no matter whether they are in the same account or different accounts. VPC Peering can work with Direct Connect or VPN to enable your on-premises data center to access multiple VPCs.
  • VPC Peering is free.
  • Routes can be configured on the console easily.

Enterprise Router

You can use VPN or Direct Connect to connect an on-premises data center to a VPC, and then use an enterprise router to connect multiple VPCs if there are in the same region.
  • Route learning is supported. There is no need to configure routes manually.
  • Multiple connections work in load balancing or active/standby mode for higher availability.
Cloud Connect
You can use Direct Connect or VPN to connect on-premises data centers to VPCs in multiple regions and then use a cloud connection or central network to connect the VPCs, so that the on-premises data centers can access all the VPCs. By working with Direct Connect, Cloud Connect provides the following two options:
  • Cloud connection: Load VPCs in different regions to a cloud connection. For this to work, you need to create a virtual gateway for each VPC that needs to communicate with the on-premises data centers.
  • Central network: Attach VPCs and Direct Connect global DC gateways in the same region to an enterprise router and then add the enterprise routers in different regions to a central network. In this way, VPCs in different regions can communicate with the on-premises data centers in multiple cities. Compared with a cloud connection, using a central network features a simpler architecture and higher scalability.
  • Route learning is supported. There is no need to configure routes manually.
  • Network connection policies can be defined flexibly.

Connecting a Single VPC to an On-Premises Data Center

You can use Direct Connect or VPN to connect a VPC to an on-premises data center.

Before connecting a VPC to an on-premises data center, you need to plan their CIDR blocks in advance to ensure that the VPC CIDR block does not overlap with the on-premises CIDR block, or communications may fail.

VPN provides an encrypted, Internet-based channel that connects an on-premises data center and the cloud.

For details, see Configuring Enterprise Edition S2C VPN to Connect an On-premises Data Center to a VPC.

In Figure 1, some workloads have been migrated to a VPC (VPC-A), and some workloads are still running on on-premises servers. With a VPN connection, on-premises servers can quickly access the cloud resources in the VPC. Compared with Direct Connect, VPN is easier to configure and cost-effective.
Figure 1 Connecting a VPC to an on-premises data center using VPN

Direct Connect establishes a dedicated network connection between an on-premises data center and the cloud.

For details, see Accessing a VPC over a Direct Connect Connection and Using BGP to Route Traffic.

In Figure 2, some workloads are running in a VPC (VPC-A) on the cloud, and some are running in the on-premises data center. A Direct Connect connection connects the on-premises data center to the cloud. Direct Connect connections are faster and more stable than VPN connections.
Figure 2 Connecting a VPC to an on-premises data center using Direct Connect

Connecting Multiple VPCs in the Same Region to an On-Premises Data Center

To connect multiple VPCs in a region to an on-premises data center, you can use Direct Connect or VPN to connect the data center to a VPC, and then use VPC Peering or Enterprise Router to connect all VPCs. In this way, the on-premises data center can access all the VPCs.
To connect VPCs to an on-premises data center, you need to plan their CIDR blocks in advance. Note the following:
  • Ensure that the VPC CIDR blocks do not overlap with the on-premises CIDR block, or communications may fail.
  • Ensure that the VPC CIDR blocks do not overlap, or communications may fail.

With VPC Peering, you can peer two VPCs in the same region, no matter whether they are in the same account or different accounts. VPC Peering can work with Direct Connect or VPN to enable your on-premises data center to access multiple VPCs.

For details, see Connecting an On-Premises Data Center to Multiple VPCs that Need to Communicate with Each Other.

In Figure 3, some workloads are running in two VPCs (VPC-A and VPC-B) in a region, and some workloads are running in the on-premises data center. The on-premises data center connects to a VPC (VPC-B) over a Direct Connect connection, and VPC-A and VPC-B are connected over a VPC peering connection. In this way, the on-premises data center can access both VPC-A and VPC-B.

Figure 3 Connecting an on-premises data center to VPCs using Direct Connect and VPC Peering

You can use VPN or Direct Connect to connect an on-premises data center to a VPC, and then use an enterprise router to connect multiple VPCs if there are in the same region.

In Figure 4, some workloads are running in two VPCs (VPC-A and VPC-B) in a region, and some workloads are running in the on-premises data center. The two VPCs and global DC gateways are attached to an enterprise router in the same region, so that the two VPCs can communicate with each other and also with the on-premises data center.

In this example, two Direct Connect connections are deployed to balance loads, improving the network performance and reliability. When both connections work normally, the network transmission capability is greatly improved. If one connection becomes faulty, the other connection can take over services, and your on-premises data center can still access the VPCs.

Figure 4 Connecting an on-premises data center to VPCs in the same region using Direct Connect and Enterprise Router

Connecting Multiple VPCs in Different Regions to On-Premises Data Centers

To connect multiple VPCs in different regions to on-premises data centers, you can use Direct Connect or VPN to connect each on-premises data center to a VPC and then use a cloud connection or central network to connect all VPCs.
To connect VPCs to an on-premises data center, you need to plan their CIDR blocks in advance. Note the following:
  • Ensure that the VPC CIDR blocks do not overlap with the on-premises CIDR block, or communications may fail.
  • Ensure that the VPC CIDR blocks do not overlap, or communications may fail.

To use a cloud connection to connect VPCs in different regions, you also need to load the virtual gateway for each VPC to the cloud connection. In this way, on-premises data centers in multiple cities can access the VPCs.

For details, see Connecting Multiple On-Premises Data Centers to Multiple VPCs in Different Regions.

In Figure 5, there are two on-premises data centers (IDC-A and IDC-B) in different cities, with each connected to a VPC over a Direct Connect connection (DC-A and DC-B). DC-A connects IDC-A in city A to VPC-A in region A, and DC-B connects IDC-B in city B to VPC-B in region B. The two VPCs and virtual gateways are connected over a cloud connection to set up a cross-region private network. In this way, VPC-A, VPC-B, IDC-A and IDC-B can communicate with each other.

Figure 5 Connecting on-premises data centers to VPCs across regions using a cloud connection

You can attach VPCs and Direct Connect global DC gateways in the same region to an enterprise router, and then add the enterprise routers in different regions to a central network. In this way, VPCs in different regions can communicate with on-premises data centers in multiple cities. Compared with a cloud connection, using a central network features a simpler architecture and higher scalability.

In Figure 6, VPCs and global DC gateways in each region are attached to different enterprise routers, so the on-premises data center in each city can access the VPCs in the corresponding region. Then the two enterprise routers (ER-A and ER-C) are connected over a central network. In this way, the three VPCs (VPC-A, VPC-B, and VPC-C) and two on-premises data centers (IDC-A and IDC-C) are on the same cloud network and can communicate with each other. In this solution, only the enterprise router in each region is added to the central network, simplifying the network architecture. Also, with global DC gateways attached to enterprise routers, VPCs can share Direct Connect connections to communicate with the on-premises data centers. Route learning of enterprise routers eliminates complex configurations and simplifies maintenance.
Figure 6 Connecting on-premises data centers to VPCs across regions using a central network
Parent Topic: Virtual Private Cloud