fig1 e illustrates a device r40 150 that is couple to part of autonomous system as123 154 note that a different reference numeral 154 is used to identify the element as123 in fig1 e than the reference numeral 144 used to reference the element as123 in fig1 d this is to clearly illustrate that at this stage of the topology determination neither of the topology inference tools that provided the topologies of fig1 d and 1e are aware that the same element as123 is identified by the other tool the residual information of fig1 e includes the identification of another subnet 192 168 5 1 24 and the identification of the autonomous system as123 in accordance with an aspect of this invention a network stitching tool is structured to determine connections among a plurality of individual networks based on the residual information that is provided with respect to these individual networks the residual information being information that is not solely related to or not known to be solely related to devices and connections that are within each individual network fig6 illustrates an example flow diagram for stitching together a plurality of network topologies based on residual information associated with each network and fig2 a 2d 3 a 3 c 4 a 4 b and 5 illustrate the application of the stitching processes to the individual networks illustrated.