SD WAN Appliances

SD WAN appliances  need to use an SD WAN controller. Every SD WAN appliance is responsible for registering its private IP address with the central controller. Once registered, the appliance is automatically and instantly forwarded traffic to the relevant network. The only exception to this rule is when an SD WAN appliance is configured to send outbound traffic to a router on the same LAN as itself and the router does not exist in the public WAN interface. In this case, the SD WAN appliance will redirect traffic to the public WAN interface and assign a public IP address (IPv4 address) to itself, allowing it to access the network while maintaining an end-to-end public IP address to the router. Only the private network of the SD WAN appliance is shared with other SD WAN appliances. For instance, if an SD WAN appliance is behind a NAT router, all private traffic will be routed through the NAT router, but the router and all of its subnets will remain private.

Cisco does not make use of NAT or WAN Virtual Private Networks (WVPs). Cisco WAN Virtual Private Networks are specifically for internal network usage and are not available for external traffic. Cisco SD WAN functionality is only available on Cisco routers that are embedded in an access device.

What is SD IP?

So how does all of this work in the vast network of managed SD WANs that we support?

So lets say that we want to quickly validate that all of the configuration in our SD WAN is correct and working correctly. The following sample SD IP configuration statement will do the trick:

Step 1: Acquire the SD IP address from the network configuration

In the Cisco Unified Controller Configuration General tab (left pane), expand All Internet Protocol Ranges, select the Private IP address as shown in Figure 1, and select Manage this IP Address. Then select the IP address entered in the lower right. In Cisco Unified CM Administration Advanced Settings General, expand Network, select the SD IP address, and then select Done.

Figure 1: Acquire the SD IP address from the network configuration

Step 2: Configure the SD IP

Log onto a Cisco Unified CM Administrative Console and log on as an administrator. Navigate to the Controller IP sub-menu and expand SD IP:

Now configure the settings as shown in Figure 2. Do not configure any additional configurations, as these options are only used for testing.

Figure 2: Configure the SD IP settings

Step 3: Save the SD IP configuration and validate

Navigate to the SD IP settings tab, and click the Save button. When completed, the configuration is ready to use on a newly-registered, operational Cisco router. If no configuration was modified during this test, validate the connectivity of the access device. Select the Cisco Access Device from the SD IP configuration list and verify connectivity to the Cisco WAN.

The benefits of Cisco Unified CM WAN Virtual Private Networks (WVPs)

In this section, we provide a number of important benefits of WVPs over normal WAN methods such as NAT and WAN Virtual Private Networks (WVPs).