Browse Prior Art Database

Multiple Uses of Link Flag Signal for Interconnect Functions

IP.com Disclosure Number: IPCOM000117701D
Original Publication Date: 1996-May-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Ocheltree, KB: AUTHOR [+4]

Abstract

In a remote link interconnect environment, it is necessary to implement a link protocol so that data transfer can be performed reliably between the connected nodes. In order to specify various link data fields used in the protocols, such as Idle, Begin of Packet, End of Packet, and CRC, methods of implementing an additional FLAG signal are employed to transmit the data field information in parallel with the link data. This "parallel" FLAG method has the advantage of maintaining high data throughput since no extra link data insertion for the field information is needed.

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Multiple Uses of Link Flag Signal for Interconnect Functions

      In a remote link interconnect environment, it is necessary
to implement a link protocol so that data transfer can be performed
reliably between the connected nodes.  In order to specify various
link data fields used in the protocols, such as Idle, Begin of
Packet, End of Packet, and CRC, methods of implementing an additional
FLAG signal are employed to transmit the data field information in
parallel with the link data.  This "parallel" FLAG method has the
advantage of maintaining high data throughput since no extra link
data insertion for the field information is needed.  Furthermore, it
is also desirable to directly detect the conditions of remote link
Reset (reset the entire node) and Synchronization (synchronize the
link while maintain data transfer) so that a connected node can be
initialized without the involvement of data packet transfer.  The
traditional implementation of the FLAG, Reset, and Sync. signals
requires multiple cable lines as shown in Fig. 1.
        *---------*                       *---------*
        |         |--- clock + data ----->|         |
        | node A  |------- FLAG  -------->| node B  |
        |         |------- Reset -------->|         |
        |         |------- Sync. -------->|         |
        *---------*                       *---------*

       Fig. 1.  Multiple Lines for...