Browse Prior Art Database

CSMA/CD LAN Continuous Carrier Handler

IP.com Disclosure Number: IPCOM000107415D
Original Publication Date: 1992-Feb-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Graves, SB: AUTHOR [+4]

Abstract

In a CSMA/CD broadband network, whenever a LAN adapter becomes "locked" in a "continuous transmission" state, a problem known as a continuous carrier occurs. This freezes the entire network.

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This is the abbreviated version, containing approximately 100% of the total text.

CSMA/CD LAN Continuous Carrier Handler

       In a CSMA/CD broadband network, whenever a LAN adapter
becomes "locked" in a "continuous transmission" state, a problem
known as a continuous carrier occurs.  This freezes the entire
network.

      This article describes a technique that provides an effective
way to isolate and remove the faulty LAN adapter which causes the
continuous carrier problem.

      Fig. 1 is a logic block diagram of a CSMA/CD LAN adapter with
the continuous carrier handler.

      Two bits in the continuous carrier handler (CCH) register are
the continuous carrier test (CCT) and the jabber/modem power-off
(JMPO).  The CCT bit is used for continuous carrier "me" or "not me"
fault testing.  The JMPO bit is used to cut off power to the modem
once a faulty "me" is identified.

      Fig. 2 is the continuous carrier identification process flow
diagram.