A method for mapping packet flows (F1, F2) onto packet data protocol contexts (PDP1, PDP2) in a communication system comprising at least a terminal, a first network node and a second network node, the method comprising: initiating an establishment of an application protocol communication session between a terminal and a remote terminal; receiving information about said application protocol communication session and at least two packet flows (F1, F2) in the second network node; agreeing to the establishment of at least two packet data protocol contexts (PDP1, PDP2); obtaining by said first network node from said second network node a packet classifier (CF1U, CF1D, CF2U, CF2D, CF3U, CF3D) for each of said at least two packet flows (F1, F2); establishing at least a first packet data protocol context (PDP1, PDP2) of said at least two packet data protocol contexts (PDP1, PDP2), in response to at least a first packet data protocol context (PDP1, PDP2) activation signaling message to said first network node; receiving a packet (415, 418) associated with said first packet data protocol context (PDP1, PDP2) in said first network node; matching said packet (415, 418) with at least one of said packet classifiers (CF1U, CF1D, CF2U, CF2D, CF3U, CF3D) to determine a first packet flow (F1, F2) among said at least two packet flows (F1, F2) in said first network node; establishing a mapping between a packet flow (F1, F2) pair, said packet flow pair comprising said first packet flow (F1, F2) and a corresponding opposite direction packet flow (F1, F2), and said first packet data protocol context (PDP1, PDP2) in said first network node; and removing in said first network node the packet classifiers (CF1U, CF1D, CF2U, CF2D, CF3U, CF3D) associated with the packet flows (F1, F2) in said packet flow pair from at least one second packet data protocol context (PDP1, PDP2) among said at least two packet data protocol contexts (PDP1, PDP2), said at least one second packet data protocol context (PDP1, PDP2) being different from said first packet data protocol context (PDP1, PDP2). initiating an establishment of an application protocol communication session between a terminal and a remote terminal; receiving information about said application protocol communication session and at least two packet flows (F1, F2) in the second network node; agreeing to the establishment of at least two packet data protocol contexts (PDP1, PDP2); obtaining by said first network node from said second network node a packet classifier (CF1U, CF1D, CF2U, CF2D, CF3U, CF3D) for each of said at least two packet flows (F1, F2); establishing at least a first packet data protocol context (PDP1, PDP2) of said at least two packet data protocol contexts (PDP1, PDP2), in response to at least a first packet data protocol context (PDP1, PDP2) activation signaling message to said first network node; receiving a packet (415, 418) associated with said first packet data protocol context (PDP1, PDP2) in said first network node; matching said packet (415, 418) with at least one of said packet classifiers (CF1U, CF1D, CF2U, CF2D, CF3U, CF3D) to determine a first packet flow (F1, F2) among said at least two packet flows (F1, F2) in said first network node; establishing a mapping between a packet flow (F1, F2) pair, said packet flow pair comprising said first packet flow (F1, F2) and a corresponding opposite direction packet flow (F1, F2), and said first packet data protocol context (PDP1, PDP2) in said first network node; and removing in said first network node the packet classifiers (CF1U, CF1D, CF2U, CF2D, CF3U, CF3D) associated with the packet flows (F1, F2) in said packet flow pair from at least one second packet data protocol context (PDP1, PDP2) among said at least two packet data protocol contexts (PDP1, PDP2), said at least one second packet data protocol context (PDP1, PDP2) being different from said first packet data protocol context (PDP1, PDP2).