Methods and devices for negotiating a policy in telecommunication networks

A method implemented in a telecommunication system, the telecommunication system comprising a first network node, a second network node and a third network node, the method comprising:

• determining, by the first network node, that a background data transfer, BDT, policy is to be applied to both a first core network and a second core network;
• in response to the BDT policy being determined to be applied to both the first core network and the second core network, transmitting, from the first network node to a second network node, a request for negotiating a common BDT policy applicable to both the first core network and the second core network;
• receiving, at the second network node, a background data transfer, BDT, policy control create request from a first network node for negotiating a common BDT policy applicable to both a first core network and a second core network;
• and
• determining, by the second network node, common BDT policies applicable to both the first core network and the second core network;
• receiving, at the third network node from the first network node, a network function discovery request for the second network node for negotiating a common background data transfer, BDT, policy applicable to both a first core network and a second core network;
• and
• transmitting, from the third network node to the first network node, a list of second network nodes.