Help Center> Enterprise Router> Best Practices> Using an Enterprise Router to Replace VPC Peering Connections> Overview
Updated on 2024-01-18 GMT+08:00
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Overview

Scenario

Before enterprise routers are available, VPC peering connections are used to connect different VPCs in the same region. VPC peering connections are suitable for simple networks because every two VPCs need a VPC peering connection. In a complex network, a large number of VPC peering connections are required, which is inconvenient for network expansion and increases O&M costs.

As a high-performance centralized router on the cloud, an enterprise router can connect multiple VPCs in the same region, making network expansion and O&M easier.

If you have a lot of VPCs that are connected by VPC peering connections, you can use an enterprise router to replace the VPC peering connections.

For details, see Enterprise Router Service Overview.

Architecture

VPC-A, VPC-B, and VPC-C are in region A and connected over VPC peering connections. To improve network scalability and reduce O&M costs, you can use an enterprise router to connect the three VPCs.

This process consists of three phases: before replacement, during replacement, and after replacement. The details are as follows:
  1. Before the replacement, VPC-A, VPC-B, and VPC-C are connected through VPC peering connections.
  2. During the replacement, VPC-A, VPC-B, and VPC-C will be connected through both VPC peering connections and an enterprise router. Large and small CIDR blocks are used to ensure that the routes of VPC peering connections and the enterprise router do not conflict.
  3. After the replacement, VPC-A, VPC-B, and VPC-C can communicate with each other through the enterprise router and you can delete the VPC peering connections.
Figure 1 Replacing VPC peering connections with an enterprise router

Advantages

Simplified networking structure, improved scalability, and reduced O&M costs

As shown in Figure 2, the networking of VPCs connected by VPC peering connections is more complex than that of an enterprise router. For example, if you have six VPCs, you need to create 15 VPC peering connections. But if you use an enterprise router, one router can connect all of your VPCs. The networking is simple and clear, making O&M and network expansion easier.

Figure 2 Networking using VPC peering connections and an enterprise router

Notes and Constraints

  • If the VPCs connected by VPC peering connections are from different accounts, you can use the sharing function of the enterprise router to connect the VPCs of different accounts through one enterprise router.
  • Replacing VPC peering connections with an enterprise router may interrupt services. Submit a service ticket and contact customer service to evaluate the replacement solution. Here are some example scenarios that services may be interrupted.
    • If resources in a service VPC have virtual IP addresses bound, the service VPC cannot be attached to an enterprise router.
    • If a service VPC is being used by ELB, VPC Endpoint, NAT Gateway (private NAT gateway), Distributed Cache Service (DCS), or hybrid DNS, this VPC cannot be attached to an enterprise router.

For details about constraints on enterprise routers, see Notes and Constraints.