and g723 are supported gateways 4 and 5 are hence equipped with dsps which can perform the conversion between different codecs such conversion between different voice codecs is also termed transcoding and it is generally known in the art how to perform real time transconding of encoded voice data streams the gateways 4 and 5 are equipped with less than 100 dsp resources in other words they have less dsp resources than would be necessary to perform transcoding on all voice calls the gateway is able to handle at the same time the present invention hence proposes to introduce a control instance that keeps track of the dsp resources in a gateway and refuses resource consuming connections that require transcoding while preserving resources for less resource consuming connections a block diagram of a media session boarder controller is shown in fig2 the session boarder controller 20 has first interface 21 and a second interface 22 for connecting to a first and second network respectively these interfaces can for example be gigabit ethernet interfaces and can receive and transmit data traffic including hundreds of voice calls at a time as well as other type of media like video and multimedia a number.