Thank you for your response.

I knew that the rules of DOT (carrier that operates first segment) and IATA (major carrier for the trip) but was not sure whether journey is one entire trip or outnound/inbound are considered two separate trips.

After I posted question here last night, was able to find out about SV and was able to get all the details including fare basis, bags allowance, tax/fees breakdown.

LH agent was also able bring up that info on her terminal too. But Air Canada customer service can not look up their own information (ticket is 014 stock)?

To answer the original question. Journey seem to define the entire trip.