100 Base - T / IEEE 802 . 12 / Packet Switching

100Base-T, IEEE 802.12, 100VGAnyLAN, packet switching, IEEE 802.3, CSMAlCD, demand priority Three recent LAN technologies look set to satisfy the ever-increasing demand for LAN bandwidth. Two of these technologies are 100Mb/s shared medium LANs: 100Base-T (aka IEEE 802.3 Fast Ethernet) and IEEE 802.12 (aka 100VG-AnyLAN or 100VG). The third technology is packet switching, which is really an extension of existing LAN bridge technology, but which offers excellent performance gains at very low cost. In this paper we describe the three technologies and provide a comparison between the two 100Mb/s LANs. We also present results that compare the measured performance of 100 Mb/s shared medium LANs with switched LANs. Given the ''holy wars" between 100Base-T and 100VG-AnyLAN we have worked hard to present the technologies on an equal footing. One of the authors is from HP, and served on the 802.12 committee. The second author is the chairperson of an IEEE 802.3 subcommittee. We hope we have achieved our goal of presenting a balanced view of these technologies.