1. A method for providing a graphical user interface in a user equipment associated to a network management system for monitoring and configuring a data network, the method comprising: storing information comprising: a data model representative of the data network, wherein said data model has a plurality of elements corresponding to devices in the data network, each of the plurality of elements comprises one or more sub elements, and each of the one or more sub elements is associated to a data type of a set of data types, a configuration database comprising configuration information, the configuration database comprising a first database configured to only store a current configuration of nodes in the data network, and a second database configured to only store a future configuration of the nodes in the data network, the first database configured to be synchronized with the data network by a controller using text-based configuration status reports in the form of CLI command sequences, a default widget library comprising a plurality of widgets, default registry data having entries, wherein the entries identify a default graphical representation for each data type of the set of data types, and the default graphical representation is defined by at least one predetermined widget from the default widget library, and customization registry data having at least one entry, wherein the at least one entry defines, based on customization input received in the graphical user interface, at least one key being associated with a customization registration, said at least one key identifying at least one element and/or sub element of the data model for which an alternative graphical representation is to be provided, and the alternative graphical representation is defined by the customization registration; receiving an input that identifies a portion of the data network of interest for display in the graphical user interface; generating a request for data from the data model based on the input; receiving the data from the data model, the data from the data model being representative for the portion of the data network of interest; generating graphical representations of current configurations of a subset of the devices in the portion of the data network of interest by determining, using the customization registry data, whether each element of the data from the data model is identified by the at least one key in the at least one entry, wherein: when it is determined that the element is identified by the at least one key in the at least one entry, generating the alternative graphical representation based on a combination of a current configuration of a device corresponding to the element from the configuration database and the customization registration that is associated with the at least one key, and when it is determined that the element is not identified by the at least one key in the at least one entry, generating the default graphical representation based on a combination of the current configuration of the device corresponding to the element from the configuration database and the at least one predetermined widget; and rendering, in the graphical user interface, the portion of the data network of interest using the graphical representations.