System for providing an enhanced and/or supplementary network connectivity to at least one client device (51, 52) being connected to a telecommunications network using a customer premises equipment device, wherein the system comprises the customer premises equipment device, a supplementary access gateway device, and the at least one client device (51, 52), wherein the supplementary access gateway device is provided to be connected to the customer premises equipment device, the customer premises equipment device being able to provide - by using a first interface of the customer premises equipment device towards a first access network of the telecommunications network - a network connectivity, using the first access network, between the telecommunications network and the at least one client device (51, 52), wherein the supplementary access gateway device is provided to be connected to a second access network (111, 211) via a supplementary access device and a second interface of the supplementary access gateway device, wherein the second access network (111, 211) is an access network of either the telecommunications network or of a further telecommunications network, wherein the supplementary access device is a mobile phone or a tablet device, wherein the system is configured such that -- enhanced and/or supplementary network connectivity is provided to the at least one client device (51, 52) using the second access network (111, 211) and the second interface of the supplementary access gateway device, this enhanced and/or supplementary network connectivity being provided to the at least one client device (51, 52) instead or besides or in addition to the network connectivity provided using the first access network and the customer premises equipment device, and -- the supplementary access gateway device is enabled to be at least logically connected to the at least one client device (51, 52) in order to provide network connectivity using both -- the first access network in addition to the customer premises equipment device, and -- the second access network (111, 211) in addition to the supplementary access gateway device, wherein the system is configured such that any software required for using the supplementary access device to establish the connection to the second access network (111, 211) is installed directly from the supplementary access gateway device, wherein the system is configured such that the supplementary access gateway device is used to establish - between the at least one client device (51, 52) on the one hand, and a server entity on the other hand - both a first communication path using the first access network and a second communication path using the second access network (111, 211). -- enhanced and/or supplementary network connectivity is provided to the at least one client device (51, 52) using the second access network (111, 211) and the second interface of the supplementary access gateway device, this enhanced and/or supplementary network connectivity being provided to the at least one client device (51, 52) instead or besides or in addition to the network connectivity provided using the first access network and the customer premises equipment device, and -- the supplementary access gateway device is enabled to be at least logically connected to the at least one client device (51, 52) in order to provide network connectivity using both -- the first access network in addition to the customer premises equipment device, and -- the second access network (111, 211) in addition to the supplementary access gateway device, -- the first access network in addition to the customer premises equipment device, and -- the second access network (111, 211) in addition to the supplementary access gateway device,