Fuzzball routers were the first modern routers on the Internet. They were DEC LSI-11 computers loaded with the Fuzzball software written by David L. Mills (of the University of Delaware). The name "Fuzzball" was the colloquialism for Mills' routing software. Six Fuzzball routers provided the routing backbone of the first 56 kbit/s NSFnet, allowing the testing of many of the Internet's first protocols. It allowed the development of the first TCP/IP routing protocols, and the Network Time Protocol. They were the first routers to implement key refinements to TCP/IP like variable-length subnet masks.
- Carl Malamud (1992). Exploring the Internet: a technical travelogue. Prentice Hall. p. 88. ISBN 0-13-296898-3.
- Fuzzball: The Innovative Router Archived 2011-05-20 at the Wayback Machine.
-  Mills, D.L. The Fuzzball. Proc. ACM SIGCOMM 88 Symposium (Palo Alto CA, August 1988), 115-122.
-  Mills, D.L., and H.-W. Braun. The NSFNET Backbone Network. Proc. ACM SIGCOMM 87 Symposium (Stoweflake VT, August 1987), 191-196
- Presentation at the NSFNET Legacy event, 2007.  Particularly page 38-48. 'The NSFnet Phase-I Backbone and The Fuzzball Router'- David L. Mills. 29 November 2007.
- Fuzzball: A page by David L. Mills, including links to some of his papers on the Fuzzball.
- Charles M. Kozierok (2005). The TCP/IP guide: a comprehensive, illustrated Internet protocols reference. No Starch Press. pp. 679–681. ISBN 1-59327-047-X.
- Technical History of NTP
- John T. Moy (1998). OSPF: anatomy of an Internet routing protocol. Addison-Wesley Professional. p. 20. ISBN 978-0-201-63472-3.