sFlow: Filter-based UDP and GRE tunnel de-encapsulation

Use sFlow to monitor ingress and egress traffic profiles for filter-based GRE and UDP tunnel de-encapsulation. sFlow support for UDP tunnel de-encapsulation enhances network monitoring with statistical sampling of network packets through firewall filters. 

This feature supports IPv4, IPv6, and MPLS payloads, where de-encapsulation and firewall actions are enabled on the ingress side. Key functionalities include de-encapsulation action mapping for reserving payload headers, handling VRF configuration for accurate packet lookup, and determining sample content based on packet structure. The device supports a sampling rate of up to 35,000 samples per second.

The behavior of sFlow for UDP de-encapsulation is consistent with that of GRE de-encapsulation, providing a unified approach to monitoring across different tunneling methods.