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Method to Initialize Multiple Network Ports in Parallel

IP.com Disclosure Number: IPCOM000123541D
Original Publication Date: 1999-Jan-01
Included in the Prior Art Database: 2005-Apr-05
Document File: 1 page(s) / 33K

Publishing Venue

IBM

Related People

LaBerge, PA: AUTHOR [+3]

Abstract

In a network switch, many ports are attached to a single bus connecting to the switch fabric. Each port is initialized by writing configuration registers and RAMs (Random Access Memories). Performing this configuration sequentially across all ports multiplies the initialization time by the total number of ports on the bus.

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Method to Initialize Multiple Network Ports in Parallel

   In a network switch, many ports are attached to a single
bus connecting to the switch fabric.  Each port is initialized by
writing configuration registers and RAMs (Random Access Memories).
Performing this configuration sequentially across all ports
multiplies the initialization time by the total number of ports on
the bus.

   Disclosed is a method to initialize all ports in parallel
by providing a method to perform a broadcast write to registers and
RAMs to all ports on a single bus.

   The register or RAM to be written in a port is selected by
a port address along with mapped bus address.  The mapped bus
address field is extended by one bit which becomes the Broadcast
Write bit.  During a register/RAM write cycle, if the Broadcast
Write bit is set active, the port select address is ignored, and the
write operation is performed on all ports.  If the Broadcast Write
bit is not set or inactive, the write operation is only performed on
the selected port.  The Broadcast Write bit is ignored for a
register/RAM read operation.

   The current implementation of the Broadcast Write bit is
used on an IBM 8-port Token-ring chip.  Up to four Token-ring chips
can be attached to the switch fabric interface bus for a total of 32
ports on this bus.  The register addressing is as follows:
    Bit 15 - 13:  Read/Write command
    Bit 12 - 8 :  Port Address (1 of 32)
    Bit 7      :  Broadcast Write
 ...