Measures for configuring a network aggregation device in a network. First routing data for a plurality of internet protocol (IP) flows configured on at least one edge device of a service provider network is identified. The edge device is located towards the service provider network from the network aggregation device. At least one utility metric for at least one IP flow in the identified plurality of IP flows is calculated. The at least one utility metric is calculated at least in part on the basis of one or more destination IP addresses associated with the at least one IP flow. A subset of IP flows from the identified plurality of IP flows is selected at least in part on the basis of the calculated at least one utility metric. Second routing data for the selected subset of IP flows is configured on the network aggregation device.