Initiating Communication Sessions from a First Computer Network to a Second Computer Network

Interface device (10) for connection between a first network (12) having a first addressing realm and a second network (16) having a second addressing realm enabling starting of sessions from a first computational device (14) communicating with the interface device via the first network to a second computational device (18) in the second network, comprising:

• a first input (24) to be connected to the first network for receiving at least one query (20) concerning the second device, which query includes at least a device name (server) and a service name (http) associated with the second device and has a first destination address (AG1) of the first addressing realm associated with the second network,
• a first output (22) for connection to the first network,
• a name and service resolving unit (40) arranged to look up a second address (AY) as well as a service port number (PHTTP) associated with a service of the second device in the second addressing realm based on the device name and the service name,
• an address and port translation table (38), and
• a control unit (32) arranged to:
• bind the received first address (AG1) and a session port number of the first addressing realm (PGHTTP) to the second address (AY) and service port number (PYHTTP) belonging the second device in the second addressing realm in the address and port translation table, and
• provide a message (22) leaving the second network as at least one answer to the query comprising the first address and the session port number of the first addressing realm to the first device, such that a session can be started from the first device to the second device where the first address and session port number of the first addressing realm and the second address and service port number of the second addressing realm are exchanged with each other in the headers of packets of the session when passing between the two networks.

System of computational devices for connection to a first network (12) having a first addressing realm, via which first network a first computational device (14) can communicate with the system and comprising a second network (16) having a second addressing realm, said second network comprising:

• a second computational device (18), and
• an interface device (10) provided between the first and second networks comprising:
• a first input (24) to be connected to the first network for receiving a query (20) concerning the second device, which query includes at least a device name (server) and a service name (http) associated with the second device and has a first destination address (AG1) of the first addressing realm associated with the second network,
• a first output (26) for connection to the first network,
• an address and port translation table (38), and
• a control unit (32) arranged to:
• bind the first address (AG1) and a session port number (PGHTTP) of the first addressing realm to a second address (PY) and a service port number (PYHTTP) belonging to the second device in the second addressing realm in the address and port translation table, and
• provide a message (22) leaving the second network as an answer to the query of the first device comprising the first address and the session port number of the first addressing realm,
• wherein the second network further comprises a name and service resolving unit (40;
• 80) arranged to look up the second address (AY) as well as the service port number (PYHTTP) associated with a service of the second device in the second addressing realm based on the device name and the service name, such that a session can be started from the first device to the second device where the first address and session port number of the first addressing realm and the second address and the service port number of the second addressing realm are exchanged for each other in the headers of packets of the session when passing between the two networks.

Computer program product (86) to be used on an interface device (10) between a first network (12) having a first addressing realm and a second network (16) having a second addressing realm, wherein a first computational device (14) can communicate with the interface device via the first network and the second network comprises a second computational device (18), said computer program product having:

• computer program code, to make the interface device execute, when said program code is loaded in the interface device:
• upon reception of at least one query (20) from the first computational device concerning the second computational device, which query includes a device name (server) and a service name (http) associated with the second device and has a first destination address (AG1) of the first addressing realm associated with the second network,
• looking up a second address (AY) as well as a service port number (PYHTTP) associated with a service of the second device in the second addressing realm based on at least the device name and service name,
• binding the first address (AG1) and a session port number (PGHTTP) of the first addressing realm to the second address (AY) and service port number (PYHTTP) of the second device in the second addressing realm, and
• answering the query with at least one message (22) leaving the second network comprising the first address and the session port number of the first addressing realm to the first device, such that a session can be started from the first device to the second device, where the first address and session port number of the first addressing realm and the second address and the service port number of the second addressing realm are exchanged with each other in the headers of packets of the session when passing between the two networks.