Browse Prior Art Database

Bundling Short Packets in an ATM or Packet Network

IP.com Disclosure Number: IPCOM000121743D
Original Publication Date: 1991-Sep-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 3 page(s) / 116K

Publishing Venue

IBM

Related People

Rogers, LS: AUTHOR

Abstract

Disclosed is a system for reducing overhead for short packets in an Asynchronous Transfer Mode (ATM) or packet network. Short packets or cells sharing common network facilities (links and queues) are collected or bundled into a single packet, thus sharing the packet control bytes and reducing overhead.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 53% of the total text.

Bundling Short Packets in an ATM or Packet Network

      Disclosed is a system for reducing overhead for short
packets in an Asynchronous Transfer Mode (ATM) or packet network.
Short packets or cells sharing common network facilities (links and
queues) are collected or bundled into a single packet, thus sharing
the packet control bytes and reducing overhead.

      Each node in the network needing to assemble or disassemble the
bundled packets would require the bundling function.  The
implementation of this function may take the form of one or more
service processors.  For each outbound network link, the bundling
function would prepare a bundle or larger packet containing all small
packets outbound on that link.  At the next node all bundles received
on inbound links would be unbundled and collected into bundles for
the next network hop.  Segments reaching their destination node would
be converted to normal packets or cells to be delivered to the
destination port.

      The bundle packets are scheduled on each network link at a rate
to match the fastest cell rate of the traffic. For 48-byte ATM cells
carrying 64 Kbps voice, this would be each 6 ms.

      In a system where there is no common clock, the bundles would
be scheduled to depart at a rate just equal to or faster than the
fastest segment rate in the system.  This will insure that there will
always be an outgoing bundle available to service each cell.  Cells
produced with a slower clock will occasionally arrive late for the
departure of the bundle.  The activity mask, described below, will
indicate no data for that channel is contained in that bundle.  The
following bundle will contain the late cell.

      When a connection is established for a short cell application,
each bundler/debundler along the path is notified.  Information for
each circuit stored at each bundler/debundler will include the link
and circuit number on which the cells will arrive and the link and
circuit number on which they are to depart.  In addition, the
bundler/debundler may also have a cell length information, thus
allowing circuits operating at different speeds to use different cell
lengths.

      Fig. 1 shows a possible bundle structure.  On a serial
communications link the bundle would be preceded and followed by
delimiting flags.  The data field portion of the bundle carries the
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