Globe of invulnerability questions

[holywhippet]

1) Is the size of the area affected by the size of the caster? It says it comes up as a 10 foot radius around the caster. So what happens if the caster is large or larger? Or is it simply a 10 foot radius sphere which doesn't include the caster's size?

2) I assume spells that are already in effect on anyone in the sphere aren't suppressed even if the caster is outside?

3) I also assume there are no restrictions on dispelling the globe.

[Vorpalchicken]

1. The globe is 20 feet across (double the radius.) There should be enough room for a huge or even a gargantuan creature. (While a 20 by 20 square is used to represent such creatures and technically the corners would be cut off, the creature isn't a cube shape that actually occupies the entire space. Really, a DM call here especially if the creature is described as 100 feet tall or something. )

2. It shouldn't prevent anything that is already cast. Also it appears that non area effect spells can affect the caster of the globe if the spell originates from within the globe.

3. It should be affected by dispel or anti magic as normal.

[Keravath]

1) It is a 10' radius around the caster. Under the area of effect rules in the PHB it states that any spell with an area of effect has a point as an origin. So in this case you would get a 20' diameter area centered on the caster independent of their size.

2) Globe of Invulnerability affects the casting of spells "Any spell of 5th level or lower cast from outside the barrier can't affect creatures or objects within it" ... it doesn't say anything about affecting existing spells and doesn't say anything about affecting concentration so existing spells should continue to function.

3) The spell prevents spells being cast on creatures and objects inside the barrier. It doesn't prevent spells being cast on the barrier itself so I would think dispel magic should function normally against a globe of invulnerability.

One other thing to keep in mind is that the globe is immobile. "An immobile, faintly shimmering barrier springs" So, although it is centered initially on the caster they can both move (or be moved) and the barrier will remain in place. This makes grappling the caster and dragging them out of the globe one of the better ways to deal with a globe of invulnerability. In addition, the globe description says nothing about spells cast from within the globe affecting other creatures either inside or outside.