Cloud Connection Overview

A cloud connection enables communication between VPCs in different regions and between VPCs and on-premises data centers.

Connecting VPCs in the same region to set up a single private network
By default, VPCs in the same region can communicate with each other after they are loaded to a cloud connection.

Figure 1 Communication between VPCs in the same region
Connecting VPCs in different regions to set up a single private network
A cloud connection helps realize secure and reliable private network communications among VPCs in different regions in addition to improving network topology flexibility.

Figure 2 Communication between VPCs in different regions
Connecting on-premises data centers to VPCs in different regions to set up a hybrid cloud network
If you want to establish connectivity between multiple on-premises data centers and VPCs in different regions, you can use Direct Connect to connect each data center to the corresponding VPC and then load all the virtual gateways and VPCs to a cloud connection.

Figure 3 Communication between on-premises data centers and VPCs across regions

**Table 1** Cloud connection quotas
Quota Type	Default Quota	Adjustable
Cloud connections allowed in each account	6	Yes Submit a service ticket.
Regions where a cloud connection can be used	6	Yes Submit a service ticket.
Network instances allowed in each region	6	Yes For cross-region communication, the quota can be increased to 10. Submit a service ticket.
Bandwidth packages for each cloud connection	1	No
Routes per cloud connection	50	Yes Submit a service ticket.

A cloud connection cannot be used to connect VPCs that have overlapping CIDR blocks, or communication will fail.
If you load a VPC to a cloud connection created using the same account, you cannot enter loopback addresses, multicast addresses, or broadcast addresses for the custom CIDR block.
If a NAT gateway has been created for any VPC you have loaded to a cloud connection, a custom CIDR block needs to be added and set to 0.0.0.0/0.
Multiple bandwidth packages with different billing modes can be bound to a cloud connection.
A cloud connection can only have one bandwidth package bound if the geographic region and billing mode of the bandwidth packages are the same.

Figure 4 shows the process of connecting VPCs using a cloud connection.

Figure 4 Cloud connection configuration process

**Table 2** Steps for configuring a central network
No.	Step	Description	Reference
1	Applying for a cross-border permit	If a VPC you want to connect is outside the Chinese mainland, you need to apply for a cross-border permit. Skip this step if communication across geographic regions is not required.	Applying for a Cross-Border Permit
2	Creating a cloud connection	To enable VPCs to communicate with each other, create a cloud connection first.	Creating a Cloud Connection
3	Loading network instances	Load the VPCs to the created cloud connection based on your network plan.	Loading a Network Instance to a Cloud Connection
4	Buying bandwidth packages	To enable normal communication between regions in the same geographic region or different geographic regions, you need to purchase at least one bandwidth package and bind them to the cloud connection. Skip this step if communication across regions or geographic regions is not required.	Buying a Bandwidth Package
5	Assigning inter-region bandwidths		Assigning an Inter-Region Bandwidth