In one embodiment, whether packet loss of link layer packets at a receiver (200) has exceeded a lost threshold is detected. Feedback is sent to a transmitter (100) indicating that a header compressor (104), for compressing higher layer packets at the transmitter, should send a less compressed header if the packet loss of the link layer packets has exceeded the lost threshold. The higher layer packets are at a higher layer than the link layer and are formed by the link layer packets. The present invention also relates to a method of establishing a communication session in a hierarchical communication system between a source party and at least one destination party. Information for the session is stored if establishing the session is blocked at a node as a result of a blocking condition at the blocking node. Establishment of the session is initiated based on the information if the blocking condition no longer exists.