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Physical Network Layer Re-synchronization Mechanism

IP.com Disclosure Number: IPCOM000122368D
Original Publication Date: 1991-Dec-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 2 page(s) / 76K

Publishing Venue

IBM

Related People

Davis, GT: AUTHOR [+4]

Abstract

Described is a re-synchronization mechanism designed to eliminate loss of synchronization in communication receivers. The technique automatically re-synchronizes communication receivers without outside intervention and through program control establishes a timing threshold associated with the re-synchronization process.

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This is the abbreviated version, containing approximately 60% of the total text.

Physical Network Layer Re-synchronization Mechanism

      Described is a re-synchronization mechanism designed to
eliminate loss of synchronization in communication receivers.  The
technique automatically re-synchronizes communication receivers
without outside intervention and through program control establishes
a timing threshold associated with the re-synchronization process.

      The re-synchronization mechanism operates in conjunction with
computer-controlled networking systems with connections made through
standard trunk line adapters.  The re-synchronization mechanism is
always active in that if a receiver becomes out of synchronization,
such as when a line is temporarily unplugged, the re-synchronization
mechanism will automatically re-synchronize the trunk line.

      When a physical layer of a communication adapter has lost
synchronization, a RED alarm is said to have occurred. A YELLOW alarm
is sent to the remote station to indicate that the station has lost
synchronization.  When a RED alarm re-synchronization occurs, the re-
synchronization code is initiated and a delay occurs before checking
for another RED alarm condition.  As a result, no RED alarm checking
is done during this period of time.  After re-synchronization is
initiated, the RED alarm still exists for a period of time. The delay
is required before looking for RED alarms again.

      In addition to the layer 1 frame synchronization, layer 1
multi- frame synchronization is mo...