Establish Connectivity Between Two Sites

To connect service networks in two sites, first complete the basic network configuration at both sites and confirm that their Tier-1 gateways are available. Then configure a DCI Gateway at each site, create a DCI link, and finally create a peering connection between the Tier-1 gateways.

The DCI link carries cross-site connectivity. The Tier-1 peering connection determines whether all local subnets of the two gateways can communicate. A DCI link and a peering connection are separate managed resources. A same-site Tier-1 peering connection does not require a DCI link.

Note: After configuring the DCI link and peering connection in ZNS, check the routing and address plans of both service networks and test connectivity. Configure application disaster recovery and external entry point switching separately.

Configure DCI Gateways at Both Sites

A cross-site peering connection requires an available DCI link. Before creating the link, prepare a DCI Gateway at each site. A DCI Gateway is a site-level resource configured in the corresponding site details.

Go to ZNS Network Center > Sites, open the first site details, and select the DCI Gateway tab.
Click Set DCI Gateway, and select member hosts in this site.
You can select one or two hosts. Their order determines active-standby priority; the first host has priority for forwarding traffic.
Specify a VTEP NIC for the selected hosts, and enter the VTEP VIP.
You can select the same NIC for all hosts or select one for each host. Use an IPv4 address from the site network plan for the VTEP VIP.
Review the member order, NICs, and VIP, then save and check the DCI Gateway status.
Changing member order can change active-standby roles and the cross-site forwarding path. Assess the impact on existing services first.
Repeat these steps for the second site.

After both sites have a DCI Gateway, you can create a DCI link.

Create a DCI Link

A DCI link connects two different sites and provides the network foundation for a cross-site Tier-1 peering connection. Before creating a link, confirm that both sites and their DCI Gateways are ready, and plan the VNI range for the link.

Go to ZNS Network Center > Site Interconnect, and click Create DCI Link.
Enter a name, and select Site A and Site B.
The two endpoints must be different sites. The encapsulation type shown on the page is VXLAN.
Enter the start and end VNI values.
Both values must be integers from 1 to 16777215, and the end value must not be less than the start value. The range must also follow the site network plan and avoid conflicts with ranges already in use.
Review both sites and the VNI range, save the link, and check its configuration status in the list.

When the DCI link is available, the page displays the corresponding link based on the sites of the two gateways during creation of a cross-site Tier-1 peering connection.

Create a Tier-1 Peering Connection

Create a peering connection between two Tier-1 gateways. A same-site connection does not require a DCI link. For a cross-site connection, confirm that an available DCI link exists between the gateway sites first.

Go to ZNS Network Center > Peering Connections, and click Create Peering Connection.
Enter a name, and select two different Tier-1 gateways.
Check the sites of both gateways and the DCI link information shown on the page. If the gateways are in different sites but no DCI link is shown, prepare the link first.
Set Connect All Local Subnets according to your requirements.
This switch is on by default and allows all local subnets of the two Tier-1 gateways to communicate. To allow only specified subnets, turn it off and enter the CIDRs of local subnets connected to both Tier-1 gateways in Advertised CIDRs. Enter one CIDR per line or separate them with English commas. You cannot switch the connectivity mode after creation. In the specified-CIDR mode, you can edit the connectivity range.
Review the gateways, DCI link, and connectivity mode, then click OK.

The peering connection appears in the list. Check its configuration status, connectivity range, and gateway relationship.

Check Cross-Site Connection Status

After creation, check the configuration status of the DCI link and Tier-1 peering connection, then test connectivity from the service networks. A Deployed status on the page does not guarantee that service traffic can reach the other site.

Locate the target record in the DCI Link list. Check the connected sites, encapsulation type, configuration status, and VNI range.
Locate the target record in the Peering Connections list. Check its configuration status, connectivity range, connectivity mode, both Tier-1 gateways, their sites, and the DCI link.
Select a test VM in each service network. Test the peer IP address and service port in the expected direction of access, and record the source and destination addresses, protocol, port, and result.
The service subnets at the two sites must not overlap. If the page shows a not configured or failed state, check both DCI Gateways, the DCI link, and the Tier-1 gateways first. If the page status is normal but access fails, check routing, the upstream network, and the service port.

Cross-site connectivity is configured when the resources at both sites are related as expected and the service network access tests pass.

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