The present solution relates a method in a first communication node (301) for rate adaptation of communication between the first communication node (301) and at least one second communication node (302). The first communication node (301) and the at least one second communication node (302) being comprised in a communication network (300). The first communication node (301) receives a message from the second communication node (302). The message comprises a communication window size of the second communication node (302). The communication window size of the second communication node (302) is stored. Then, the first communication node (301) obtains the communication window size of the first communication node (301), i.e. its own communication window size. The first communication node (301) transmits a message to the second communication node (302). The message comprises the obtained communication window size of the first communication node (301).