Browse Prior Art Database

Bi-Directional Adapter for Multi-Media Network Applications

IP.com Disclosure Number: IPCOM000116569D
Original Publication Date: 1995-Oct-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 120K

Publishing Venue

IBM

Related People

Feeney, JW: AUTHOR [+3]

Abstract

Disclosed is an asynchronous network and the associated network adapters required to interface to the network for multi-media and video-on-demand applications. The solution applies to systems wherein a plurality of nodes are interconnected by a multi-stage network comprised of cascaded switches. Each node transmits messages comprised of multi-media data or video data through the network to any other node. The Figure shows a typical connection of Node 1 sending data to Node N. A specific example for video-on-demand systems, requires that video data be read from storage discs attached to Node 1 and transferred through the network to Node N, which then sends the video data over telephone or cable lines to the viewer.

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Bi-Directional Adapter for Multi-Media Network Applications

      Disclosed is an asynchronous network and the associated network
adapters required to interface to the network for multi-media and
video-on-demand applications.  The solution applies to systems
wherein a plurality of nodes are interconnected by a multi-stage
network comprised of cascaded switches.  Each node transmits messages
comprised of multi-media data or video data through the network to
any other node.  The Figure shows a typical connection of Node 1
sending data to Node N.  A specific example for video-on-demand
systems, requires that video data be read from storage discs attached
to Node 1 and transferred through the network to Node N, which then
sends the video data over telephone or cable lines to the viewer.
The reverse transfer direction is also required, where new video data
(such as a new movie) arrives over the telephone lines into Node N,
is sent through the network to Node 1, and stored on the disc for
viewing later.  This example demonstrates that multi-media and video
systems require bi-directional transfers through the network.  The
disclosed network features bi-directional network adapters at each
node, which support the multi-media bi-directional functions using
only a single adapter.  Each bi-directional adapter has a FIFO
(First-In-First-Out storage buffer) associated with each direction,
for a total of two FIFOs per adapter.  One FIFO (called the Send
FIFO) sends messages to the network, while the other FIFO (the
Receive FIFO) receives messages from the network.

      The unique characteristic of the bi-directional FIFOs in each
adapter is that they perform more functions than usually provided by
standard FIFOs.  FIFOs are normally used to smooth the flow of data;
i.e., to buffer the data being sent to the network to adapt to the
transfer rate of the network, or to buffer the data being received
from the network until the associated node can receive the data at
the transfer rate it supports.  The disclosed bi-directional FIFOs
perform the additional functions of rerouting messages around network
failures and retransmitting erroneously received messages.  This
efficiently provides multi-media systems with built-in, real-time
fault correction.

      For the video data example, data is fetched from a storage
disc under the control of a node attached to the network via a
bi-directional FIFO adapter.  The video data is first stored as a
message to the Send FIFO in the bi-directional adapter (the FIFO that
sends data to the network).  Then the adapter becomes active and
tries to transmit the message across the network.  A message contains
a header which informs the sending adapter of the destination node
across the network where the message is to be sent (Node N in the
example).  Based on the header the adapter attempts to form a
connection across the network to the destination node.  The disclosed
network contains several altern...