Method for allocating a sub-network to a communication terminal in a communication network with a plurality of sub-networks , and a base station and a management entity or only a base station , wherein one sub-network identifier is allocated to each sub-network , with: reception , by the base station , of a connection request for establishing communication across a specified sub-network together with an identification from the communication terminal , wherein the identification comprises a sub-network-identifier of the specified sub-network of the communication network ; extraction , by the base station , of the sub-network identifier from the received identification ; selection , by the base station or the management entity , of the specified sub-network from the plurality of sub-networks of the communication networks based on the extracted sub-network identifier ; and allocation , by the base station or the management entity , of the specified sub-network to the communication terminal for communication in the communication network , characterized in that the identification comprises at least one of the following identifications: an International Mobile Subscriber Identity (IMSI), wherein the sub-network identifier is located in the Mobile Subscriber Identification Number Field or in the Mobile Network Code Field of the IMSI; an eID with the sub-network-identifier on an eSIM in the communication terminal ; a network identifier of the communication network with the sub-network-identifier ; an International Mobile Station Equipment Identity with the sub-network identifier . reception , by the base station , of a connection request for establishing communication across a specified sub-network together with an identification from the communication terminal , wherein the identification comprises a sub-network-identifier of the specified sub-network of the communication network ; extraction , by the base station , of the sub-network identifier from the received identification ; selection , by the base station or the management entity , of the specified sub-network from the plurality of sub-networks of the communication networks based on the extracted sub-network identifier ; and allocation , by the base station or the management entity , of the specified sub-network to the communication terminal for communication in the communication network , characterized in that the identification comprises at least one of the following identifications: an International Mobile Subscriber Identity (IMSI), wherein the sub-network identifier is located in the Mobile Subscriber Identification Number Field or in the Mobile Network Code Field of the IMSI; an eID with the sub-network-identifier on an eSIM in the communication terminal ; a network identifier of the communication network with the sub-network-identifier ; an International Mobile Station Equipment Identity with the sub-network identifier . an International Mobile Subscriber Identity (IMSI), wherein the sub-network identifier is located in the Mobile Subscriber Identification Number Field or in the Mobile Network Code Field of the IMSI; an eID with the sub-network-identifier on an eSIM in the communication terminal ; a network identifier of the communication network with the sub-network-identifier ; an International Mobile Station Equipment Identity with the sub-network identifier . <EOS>