Ensuring connectivity of CPE devices with SD-WAN Controllers

CPE devices establish a connection with SD-WAN Controllers via the OpenFlow protocol in the control plane through all WAN interfaces: a TCP session is established with all SD-WAN Controllers through each WAN interface of the CPE device.

The diagram below shows the principle of establishing connections between a CPE device and SD-WAN Controllers.

Establishing connections between SD-WAN Controllers and a CPE device

In the example above, in a cluster of three controllers and a CPE device six TCP sessions are established with two WAN interfaces:

• 10.0.1.1 → ctl1:6653
• 10.0.2.1 → ctl1:6654
• 10.0.1.1 → ctl2:6653
• 10.0.2.1 → ctl2:6654
• 10.0.1.1 → ctl3:6653
• 10.0.2.1 → ctl3:6654

Only one session is a primary session at any given time. The parameters for switching and restoring the main session are specified when configuring the connection of the CPE device to the SD-WAN network.