The invention relates to a method 30 in a packet forwarding device 2 in an Internet Protocol, IP, network 10 for congestion control. The method 30 comprises: receiving 31 an IP packet 20 originating from a first network node 11 and addressed to a second network node 3; determining 32 a congestion status on a network path from the second network node 13 to the first network node 11; and entering 33, for a congestion status indicating congestion, congestion information into a header 21, 22 of the IP packet 20, the congestion status congestion information notifying the second network node 13 about congestion present on the network path. The invention also relates to a packet forwarding device 12, a computer program 43 and computer program product 44.