A method for performing, for the benefit of a reference provider, ISP, having a set of users, connectivity evaluations over a data communication network, said connectivity evaluations being made in relation to at least one provider, ISP, of interest (12, 14), including the steps of: - selecting a plurality of autonomous systems capable of forming at least one between a traffic source and a traffic destination for the users of said reference provider through the same reference provider. - supplying tables of Border Gateway Protocol BGP type (BGP1,..., BGPm) containing information on paths available on said data communication network for the routing of said traffic with regard to the autonomous systems of said plurality, - extracting from said tables the paths of BGP type inherent to said at least one provider of interest (12, 14), by finding out the paths that contain the respective number of autonomous system,, for said at least one provider of interest (12, 14), - extracting for each autonomous system of said plurality, oriented sub-paths between each said autonomous system and said at least one provider of interest (12, 14), by identifying for each sub-path the relating number of hops, - identifying, for each autonomous system of said plurality, at least one between the forward traffic volume and the backward traffic volume with regard to the users of said reference provider, - determining, for each of said sub-paths respective connectivity contributions as a function of said relative number of hops and of said at least one traffic volume (FI,DI), - determining, for each autonomous system of said plurality, the total connectivity values accumulating the connectivity contributions determined for the oriented sub-paths extracted for said each autonomous system, and - accumulating the total values of connectivity determined for the autonomous systems of said plurality, so as to obtain total connectivity values relating to said at least one provider, ISP, of interest (12, 14). - selecting a plurality of autonomous systems capable of forming at least one between a traffic source and a traffic destination for the users of said reference provider through the same reference provider. - supplying tables of Border Gateway Protocol BGP type (BGP1,..., BGPm) containing information on paths available on said data communication network for the routing of said traffic with regard to the autonomous systems of said plurality, - extracting from said tables the paths of BGP type inherent to said at least one provider of interest (12, 14), by finding out the paths that contain the respective number of autonomous system,, for said at least one provider of interest (12, 14), - extracting for each autonomous system of said plurality, oriented sub-paths between each said autonomous system and said at least one provider of interest (12, 14), by identifying for each sub-path the relating number of hops, - identifying, for each autonomous system of said plurality, at least one between the forward traffic volume and the backward traffic volume with regard to the users of said reference provider, - determining, for each of said sub-paths respective connectivity contributions as a function of said relative number of hops and of said at least one traffic volume (FI,DI), - determining, for each autonomous system of said plurality, the total connectivity values accumulating the connectivity contributions determined for the oriented sub-paths extracted for said each autonomous system, and - accumulating the total values of connectivity determined for the autonomous systems of said plurality, so as to obtain total connectivity values relating to said at least one provider, ISP, of interest (12, 14).