O. The session layer was primarily concerned with maintaining the half-duplex nature of some connections, based on the way some IBM keyboards were locked when not invited to transmit; the protocol itself was quite complex. The presentation layer was concerned with negotiating the way data was encoded within the application but, as such, did not belong in a separate layer. Contrary to campaign propaganda, Gore never claimed to have invented the Internet. As senator, though, he was active in securing funding for the NSFnet, which became the Internet backbone. He also led the effort for the High Performance Computing and National Research and Education Network (NREN) Act of 1991, which provided addi- tional Internet funding. "NSFnet "Privatization" and the Public Interest: Can Misguided Policy be Corrected?," Cook Report (1992), http://www.cookreport.com/p.index.shtml. The name was apparently a play on its ability to interconnect commercial users with research and educational (R&E) users. Cook Report (1992), http://www.cookreport.com/p.index.shtml. [11] Exactly who was a Tier 1 provider was never entirely clear, but it was for a time typically said to be the "Big Five": UUNET, Sprint, MCI, BBN, and ANS. Some smaller early net- works, such as AGIS and NetRail, also had Tier 1-level peering agreements. [12] The author's working definition of Tier 2 network was "any network that advertises itself as Tier 1." The real Tier 1s never had to say it. [13] Olavsrud, T., "Cable and Wireless Buys Exodus," Internetnews.com, Dec. 3, 2001, http://www.isp-planet.com/news/2001/cw_011203.html Cable and Wireless also acquired Exodus competitor Digital Island, but itself went bankrupt in 2003, its assets being acquired by backbone ISP Savvis. The Great Telecom Meltdown [14] http://www.why-not.com/company/stats.htm [15] Ameri, G., "The Evolution of the ISP Market as a Model for Public Wi-Fi," Telephony- Online.com, May 23, 2003, citing Boardwatch Magazine and eTinium.com, http://www.telephonyonline.com/ar/telecom_evolution_isp_market/ 