Abstract: The invention relates to a method and a communication system comprising at least one first network element connectable to a second network element. At least one of the first and second network elements use one of two or more selectable modes for communicating with another network element. One or both of the network elements, or a third network element, which is connectable with the first and second network elements, performs a mode selection procedure for selecting the same mode for bidirectional communication between the network elements. The modes preferably are different codec types, channel-coding schemes, or radio interface protocol types. The first and/or second network elements may be portable terminal equipments and the third network element preferably is a support node or a means providing a support function such as a CSCF. The mode selection ensures use of one and the same mode, such as a codec, in uplink and downlink directions enabling IP telephony in UMTS using SIP protocol.

Abstract: A method and a communication system which includes a first network element, e.g. portable terminal, connectable to a second network element. One of selectable modes is used for communication. A network element is adapted to perform a mode selection procedure for selecting the same mode for bidirectional communication between the network elements. The mode selection ensures the use of one and the same mode in uplink and downlink direction and thus enables e.g. IP telephony in UMTS using SIP protocol. The invention provides for facilitating a VoIP communication session by way of a radio link with a mobile station. The mobile station forms a QoS (Quality of Service) information element for communication to a radio access network portion. The QoS information element is indicating whether to remove packet header information of the data packets to be communicated upon the radio link pursuant to the communication session.

Abstract: The invention relates to communications systems, and particularly to enhancing tolerance to failures in network elements and transmission systems. The fault tolerance is achieved by providing two or more active ATM permanent virtual channel (PVC) connections between a core network element and an access network element, and providing a separate ATM interface unit for each such ATM PVC connection in the core network element. The user and signalling traffic is distributed among these active connections and interface units. In case of a failure in one of the ATM PVC connections or interface units, the communication is maintained over the other connection(s) and interface unit(s). Thus, only part of the transport capacity is lost, and a total block of communication is avoided. Any new communication will be setup over the other connections.