  In this paper we present a classification of the possible upper ramification
jumps for an elementary abelian p-extension of a p-adic field. The fundamental
step for the proof of the main result is the computation of the ramification
filtration for the maximal elementary abelian p-extension of the base field K.
This is a generalization of a previous work of the second author and Dvornicich
where the same result is proved under the assumption that K contains a
primitive p-th root of unity. Using the class field theory and the explicit
relations between the normic group of an extension and its ramification jumps,
it is fairly simple to recover necessary and sufficient conditions for the
upper ramification jumps of an elementary abelian p-extension of K.
