Browse Prior Art Database

Concentrator Ring Protection Function

IP.com Disclosure Number: IPCOM000112231D
Original Publication Date: 1994-Apr-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 62K

Publishing Venue

IBM

Related People

Love, RD: AUTHOR [+2]

Abstract

This invention discloses a relatively simple procedure for assuring that any invalid lobe attachment does not take the ring down for more than a few milliseconds.

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

Concentrator Ring Protection Function

      This invention discloses a relatively simple procedure for
assuring that any invalid lobe attachment does not take the ring down
for more than a few milliseconds.

      All it takes to gain access to the token ring is a battery
voltage applied to the right pins of a data connector.  Whether this
is done accidentally, or by a station operating at the wrong speed,
or maliciously, the ring can be taken down for various lengths of
time depending on the specific fault, and on the recovery procedure.

      This invention relates to the use of an intelligent
concentrator which controls access of stations to a LAN connected in
a logical ring.  A specific implementation could be a Token Ring LAN.
Each time a station enters the ring, there is a short transient
during which data may not be able to be transmitted.  However,
shortly thereafter, the ring is again ready to propagate data.  If,
however, the newly activated station is defective, or is operating at
the wrong speed, the ring will not progress through the transient
phase to the ready phase.  Instead, it will progress to an error
state during which time no data may be transmitted across the ring.
This error state may persist from several seconds, to indefinitely.
Even as a several second condition, the effect of the error can be
serious degradation of critical LAN services.

      The intelligence within a concentrator detects the fact that
the ring has been disabled following the insertion of a station
attached to a previously inactive lobe.  Specifically, each time a
lobe is inserted into the ring, a timer within the concentrator is
started.  If after a set time the rin...