  We consider the supersymmetry algebras of the 10 and 11 dimensional maximal
supergravities. We construct expressions from which the topological charge
structure of the algebras can be determined in supersymmetric curved
backgrounds. These are interpreted as the topological charges of the 1/2-BPS
states that are found in the theories. We consider charges for all the M-, NS-
and D-branes as well as the Kaluza Klein monopoles. We also show that the
dimensional reduction relations between the 11-d and IIA charges, and T-duality
relations of the IIA and IIB charges match those found for the branes
themselves. Finally we consider the massive versions of the IIA and 11-d
theories and find that the expressions for the charges, with a slight
modification, are still valid in those instances.
