ANY researchers want to overhaul the Internet, which has become increasingly creaky with its worms and viruses, bottlenecks and crowds. But their chances of trying out bold changes are limited. Few companies would welcome any tinkering that could disrupt a network. Now, the gap between what network researchers can do on paper and what is required for practical demonstrations has narrowed. A consortium of university and industrial scientists has created a network designed to test a new generation of tools that may one day lead to a smarter, more secure Internet that can spot network problems like traffic jams and worms long before they affect individual computers. Full Story