A method and packet switched cellular telecommunication system wherein data flows from a terminal are aggregated into one or more Multi Protocol Label Switching (MPLS) Label Switched Path (LSP) based on at least one criterion. In a first embodiment, the data flows are aggregated into LSP(s) based on a Quality of Service (QoS) class of each such data flows, by a Network Node, such as a Radio network Controller (RNC) or a Serving GPRS Support Node (SGSN). In a second embodiment, the data flows or LSPs are aggregated into another LSP(s) based on the destination routing area. The LSP aggregation is performed by an Edge Node of the routing area, such as a Gateway GPRS Support Node (GGSN). In a first variant of the 2.sup.nd embodiment, the aggregation is used for macro-mobility, while in yet another variant the same aggregation is used for defining a virtual private network.