In the Oxygen release, there were 3 main changes developed for Service Function Chaining.

• Statistics were added for Rendered Service Paths (RSPs)
  • An RSP is basically a Service Chain
  • Statistics can be queried for individual or all RSPs, which allows for better usability and debugging
• Better Data Model management
  • Previously, if ODL was restarted, information about Rendered Service Paths (RSP) would be lost (since it was only in the Operational data store).
  • Now all of the RSP information is maintained after restarting ODL, making SFC more robust and production ready.
• Improved support for legacy VNFs
  • Support was added for bump-in-the-wire VNFs.
  • bump-in-the-wire VNFs use separate interfaces for upstream ingress traffic and downstream ingress traffic to be able to determine the directionality of the packets.