Difference between UVM_DEFAULT and UVM_ALL_ON

// A=ABSTRACT,

// Y=PHYSICAL,
// F=REFERENCE,

// S=SHALLOW,

// D=DEEP
// K=PACK,

// R=RECORD,

// P=PRINT,

// M=COMPARE,

// C=COPY
//--------------------------- AYFSD K R P M C
parameter UVM_DEFAULT     = 'b000010101010101;
parameter UVM_ALL_ON      = 'b000000101010101;

So, UVM_DEFAULT turns on the "D"EEP bit, whereas UVM_ALL_ON has it turned off.

(You can see it in src/base/uvm_object_globals.svh file (uvm 1.1c or later))