Retaining capability of handling original type messages in an upgraded computer system

摘要

The present invention relates to a method, a gateway (10), an internal network, a computer program product and a computer program element, where the gateway includes a first port (30) connected to an external network for transmission of messages according to a first protocol and having a first address according to the first protocol, where transmitted messages comprise messages including embedded messages according to a second protocol and original messages according to the first protocol, a second port (32) connected to a first part of the internal network and a control unit (36), which assigns the second port as a port to be used for all messages not including embedded messages, assigns a second address to the second port, which is closely related to the address of the first port, and informs the first part of the internal network about the second port and its address.