A method is provided for estimating a number of digital subscriber line
nodes (220, 230) required to supply, from a line supply source (200), a
geographically distributed network of substantially sequentially numbered
twisted pair lines with digital subscriber line service. The method
comprises the steps of: storing, in number order, data entries for every
twisted pair line of the network, each data entry comprising a pair number
and a line length of the respective twisted pair line in relation to the
line supply source (200); sorting the entries stored in the database by
line length; isolating those sorted entries whose twisted pair lines have
a line length greater than a predetermined maximum line length in relation
to the line supply source (200); sorting the isolated entries by number;
and discriminating, from the sorted isolated entries, the presence of
discrete groupings of substantially contiguous entries.
