A method and arrangements for enabling authentication of a communication device is suggested, where a network node, capable of operating as an authentication server does not have to store all state related information relevant for a roundtrip of an authentication session. Instead of storing all this information, at least a part of it is provided to the authenticator or the communication unit, for later retrieval in a subsequent response. Based on the state related information provided in the response, the network node is capable of reproducing a state associated with a respective roundtrip. By repeating the mentioned process for a required number of roundtrips, an authentication session can be executed, where less state related information need to be stored at the mentioned network node.