Telemetry collection and analysis for SD-WAN tunnels

An apparatus, comprising:

• one or more network interfaces to communicate with a network;
• a processor coupled to the network interfaces and configured to execute one or more processes;
• and
• a memory configured to store a process executable by the processor, the process when executed configured to:
• send, by a head-end device of a network tunnel in the network, Bidirectional Forwarding Detection (BFD) probes along the network tunnel to a tail-end device of the network tunnel, to collect telemetry regarding the network tunnel;
• monitor an overhead associated with sending the BFD probes along the network tunnel;
• determine whether the overhead associated with sending the BFD probes along the network tunnel is unacceptable;
• and
• when it is determined that the overhead associated with sending the BFD probes along the network tunnel is unacceptable, switch from sending BFD probes along the network tunnel to modifying data traffic sent via the network tunnel by inserting information into data packets sent by the head-end device to the tail-end device, to collect telemetry regarding the network tunnel that is computed by the tail-end device based on the information inserted into the data packets sent by the head-end device.

A tangible, non-transitory, computer-readable medium storing program instructions that cause a head-end device of a network tunnel in a network to execute a process comprising:

• sending, by the head-end device, Bidirectional Forwarding Detection (BFD) probes along the network tunnel to a tail-end device of the network tunnel, to collect telemetry regarding the network tunnel;
• monitoring, by the head-end device, an overhead associated with sending the BFD probes along the network tunnel;
• determining, by the head-end device, whether the overhead associated with sending the BFD probes along the network tunnel is unacceptable;
• and
• when the head-end device determines that the overhead associated with sending the BFD probes along the network tunnel is unacceptable, switching, by the head-end device, from sending BFD probes along the network tunnel to modifying data traffic sent via the network tunnel by inserting information into data packets sent by the head-end device to the tail-end device, to collect telemetry regarding the network tunnel that is computed by the tail-end device based on the information inserted into the data packets sent by the head-end device.