Current the src of a path request in a non-core PS must either be Zero or the local AS. For the new lookup strategy (#2454) we have the following requests

• Down Segs:
  • src: nil
  • dst: destination AS
• Core Segs:
  • src: local core AS
  • dst: any core AS
• Up Segs:
  • src: nil or local AS
  • dst: local core AS