Boxing & unboxing is the process of converting a primitive value into an object oriented wrapper class (boxing), or converting a value from an object oriented wrapper class back to the primitive value (unboxing).
The Old Dalaran will stay in Northrend, so yes, mages are going to have 2 portals to dalaran (one to Northrend and one to the Broken Isles)
1 There is a portal to Dalaran in both the Shrine of Seven Stars (Alliance) and the Shrine of Two Moons (Horde). 2  Anyone at any level with 2 can get to Dalaran as of Patch 4.2, as all players now have the Dalaran flight path by default at player creation time. Anyone who is at least level 74 can get [74] The Magical Kingdom of Dalaran from any of several members of the Kirin Tor, which will portal them to Dalaran until you complete the quest. 2  A set of crystals, (Teleport to Violet Stand Crystal and Teleport to Dalaran Crystal), can be used.