For example DELL EqualLogic supports and leverage DCB (PFC, ETS and DCBX).
iSCSI-TLV is a part of DCBX. However the DCB protocol primitives must be supported end to end so if one member of the chain doesn't support it than it is useless.
How DCB makes iSCSI better is deeply explained here.
So think twice if you really want converged network (aka unified fabric) or dedicated iSCSI network is better option for you.