It is provided a method for enabling an SCTP packet to be encapsulated in a UDP packet the method being performed by a source network node. The method comprises the steps of: obtaining a source number based on an identifier of the source network node; obtaining a destination number based on an identifier of a destination network node; generating an SCTP packet, which comprises setting a source port of the SCTP packet to a predefined port number and setting a destination port of the SCTP packet to the destination number; generating a UDP packet, which comprises setting a source port of the UDP packet to the source number and setting a destination port of the UDP packet to the destination number; encapsulating the SCTP packet in the UDP packet; and sending the UDP packet for transport to the destination network node.