For many years, ethernet has been the mainstay for TCP/IP and local area networking, and issues specific to wide area and long haul networks have not been adequately addressed. The advent of FDDI and HIPPI standards, which are, respectively, one and two orders of magnitude faster then Ethernet, and high speed cross country links, are causing what used to be experimental issues to become everyday problems. This paper will cover some of these issues, as they relate to the TCP/IP protocols, and the work that has happened at Cray Research in the development of the UNICOS† operating system to address these issues.