Patent ID: 7792092

Claim:
A method, comprising: transmitting data over a data transmission network from a first circuit switched transmission line through a first circuit switched network node towards a second circuit switched network node that is coupled to a second circuit switched transmission line; employing, in the data transmission network, an IP protocol for transmissions from said first circuit switched network node, which receives data from said first circuit switched transmission line, towards said second circuit switched network node, said data being destined for transmission into said second circuit switched transmission line; using an IP protocol datagram to transmit data received from the first circuit switched transmission line towards the second network node; forming a header for said IP protocol datagram based at least partly on circuit switched channel identifying parameters, which identify at least one channel in the second circuit switched transmission line, and an IP protocol address of the second network node; and indicating within said IP protocol datagram separately for each of a plurality of time slots known to at least one of said first and second circuit switched network nodes, whether the IP protocol datagram carries data belonging to a channel corresponding to the time slot, and when it is indicated that the IP protocol datagram does not carry data belonging to the channel, the second circuit switched network node enables the reception of data to that channel from other sources from an IP-network in a non-consecutive manner.