Which two of the following statements is true regarding BNG$?($Choose two$)$ XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

$1.$BNG does not support the use of a configurable AAA User$-$Name attribute.

$2.$The BNG supports the use of a configurable AAA User$-$Name attribute.!!!!!!!!!!!!!!!!!!!!!

$3.$AAA configuration in BNG is based on the server groups. $!!!!!!!!!!!!!!!!!!!!!!!$

$4.$AAA configuration in BNG is not based on the server groups.