Browse Prior Art Database

Method for Establishing Ethernet Mode Compatibility

IP.com Disclosure Number: IPCOM000113944D
Original Publication Date: 1994-Oct-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 90K

Publishing Venue

IBM

Related People

Panella, JL: AUTHOR [+2]

Abstract

Disclosed is a method for determining whether a workstation or hub in an Ethernet network is a 10BASET or Isochronous device, and for changing the mode of Isochronous devices to achieve compatibility within the network. The four possible connection configurations are an Isochronous Ethernet workstation connected to either an Isochronous Ethernet hub or to a 10BASET Ethernet hub, and a 10BASET Ethernet workstation connected to either an Isochronous Ethernet hub or to a 10BASET hub.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Method for Establishing Ethernet Mode Compatibility

      Disclosed is a method for determining whether a workstation or
hub in an Ethernet network is a  10BASET or Isochronous device, and
for changing the mode of Isochronous devices to achieve compatibility
within the network.  The four possible connection configurations are
an Isochronous Ethernet workstation connected to either an
Isochronous Ethernet hub or to a 10BASET Ethernet hub, and a 10BASET
Ethernet workstation connected to either an Isochronous Ethernet hub
or to a 10BASET hub.

      The Isochronous Ethernet is an extension of the 10BASET
Ethernet, providing a logical migration path from 10BASET Ethernet to
enable multimedia applications, such as video servers and
videoconferencing.  The Isochronous Ethernet adds 6 Mbits/s of full
duplex data transmission capability to the existing 10 Mbits/s of the
10BASET Ethernet.   An Isochronous Ethernet device, whether a
workstation or a hub, is capable of operating in either an
Isochronous Ethernet mode or a 10BASET mode.  The physical
connections of the emerging Isochronous Ethernet standard (1) and of
standard 10BASET Ethernet (2) are similar, with both of these systems
using RJ45 connectors to a cable having four wires in the form of
Unshielded Twisted Pairs (UTP).

      A 10BASET workstation, or DTE, emits a "heartbeat" pulse every
100 ms.  This pulse, which can be detected by either a 10BASET or
Isochronous hub, provides a way of handling the connection of a
10BASET workstation to either type of hub.  Specifically, if an
Isochronous Ethernet hub detects this pulse, it switches to a 10BASET
mode for communication with a 10BASET workstation.

      An Isochronous Ethernet Workstation emits a "heartbeat" pulse
periodically, with the time between pulses being a submultiple of 100
ms, such as 50 ms, 33.3 ms, or 25 ms.  However, a pure 10BASET hub,
looking for a "heartbeat" pulse, will find one, coming from either a
10BASET or an Isochronous Ethernet workstation.

      The Figure is a block diagram showing a method by which an
Isochron...