Hi!

I checked expedia.com for routing rules and comes out:

MPM - AT 4506 VIA NORTH ATLANTIC
INDUSTRY FARE TYPE - XPN - INSTANT PURCHASE NONREFUNDABLE
PFCS MAY VARY BY RTG
ROUTING MPM MPM TRVL PERMITTED

I see from other searches I guess:
Routing 1 : non-stop
Routing 3: one connection (e.g. DTW-ORD/DFW-STL)
But what is MPM?

Also, concerning transfer, it said:
TRANSFERS - 2 INTERLINE PERMITTED OUTBOUND 1 INBOUND 1 FURTHER RESTR APPLY SEE TEXT RULE UNLIMITED ONLINE PERMITTED

Then means basically I can connect within US as many times as I can.But will there any restriction for that?
(e.g. will I not allowd to go from east/central city to west coast gateway?)

Thanks and happy travel!