Interlining within STAR Alliance.
 

I saw this wickedly interesting routing for my trip.

But on each segment I will be on 2 different carriers. The carriers involved on the outbound flight are UA & LH. Inbound flights will be OS-AC inbound. This gives me oppurtunity to transit via VIE & YYZ, airports i have never been through before.

My doubts about this itinerary are:

1. Which airlines luggage rules would i have to follow ?
2. Will my check in luggage be transferred between the various carriers or do i
have to check it in at each transit point ?

I would say that as long as you can show then ticketing, you should be able to check your bags all the way through. I'll be doing a similar check in later this year (flying to Germany on US, and then a seperate flight on LH to MUC).

Should be able to through check bags upon showing the other ticket. BD is about the only *A airline that won't interline with other *A.

Each ticket will have its own checked baggage allowance. If you want to be absolutely sure not to get charged excess then take no more than the lesser one.