This read-create object specifies, for a preferred route entry, how many leading network elements are considered integral to that preferred route, out of a maximum of 20. It defines the length of the explicit path segment the network must honor at the start of the route. An admin configuring a preferred route to force traffic through specific initial nodes/ports before falling back to normal PNNI routing would set this count to match the number of network elements they've defined in the route.