Browse Prior Art Database

Simplex, Unreliable Connection Using Lan Group Addressing

IP.com Disclosure Number: IPCOM000105024D
Original Publication Date: 1993-Jun-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 4 page(s) / 149K

Publishing Venue

IBM

Related People

Baugher, MJ: AUTHOR

Abstract

This invention describes the properties of a new type of communications connection which is simplex (or asymmetric as opposed to duplex), uses error detection but not error correction (no retransmission), which ensures that all packets sent are ordered (unlike connectionless or datagram service) and which uses local area network group addressing (e.g., IEEE 802.5 group addressing) for connection-oriented service from a single source to one or more sink endpoints.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 35% of the total text.

Simplex, Unreliable Connection Using Lan Group Addressing

      This invention describes the properties of a new type of
communications connection which is simplex (or asymmetric as opposed
to duplex), uses error detection but not error correction (no
retransmission), which ensures that all packets sent are ordered
(unlike connectionless or datagram service) and which uses local area
network group addressing (e.g., IEEE 802.5 group addressing) for
connection-oriented service from a single source to one or more sink
endpoints.

      Efficient group addressing is needed by many multimedia
applications, such as desktop teleconferencing, where flows have
multiple destinations.  Conventional connections (e.g., OSI, IEEE
802.2, Netbios, SNA) are binary, duplex connections which provide
reliable and ordered service.  The invention is an n-ary, simplex
connection which provides a range of quality of service for
throughput, delay, error, reliability, and order.  Unidirectional
(simplex), unreliable (error detection without correction) and
multicast service is available today only for connectionless or
datagram communications.  The invention contained in this paper
provides a simple extension to these services for ordered multicast
which are needed by multimedia applications.

      Background - Many, if not most, multimedia applications involve
interpersonal group communications.  Binary connections, however,
require multiple sends to transmit messages to multiple endpoints.
If the connection is defined around group addressing for LAN
environments, then a message can be sent to multiple destinations
with a single send operation.  Most LANs have a special form of
address structure for groups where more than one station can use the
same address.  As the number of group addresses supported on

      LAN adapters increases, group addressing can be more widely
used, not only in workstations, but in the intermediate stations
along a route (e.g., bridges and gateways); group addressing can be
used to efficiently form a route for a multicast (or broadcast)
connection.

      There is a need to combine the unidirectional (and possibly
unreliable) flow of datagram service with the order, throughput,
delay and other guarantees associated with connection-oriented
service.  Multimedia flows such as sound and video are often simplex
- media flows from one device (e.g., a camera) to another device
(e.g., a video window).  Such flows are often delay sensitive, but
can tolerate a certain amount of transient loss.  Messages usually
cannot be delivered out of order, however, or exceed a delay
constraint.  Present-day connections are usually defined to be
reliable and ordered.  The simplex connection will support
unreliable, ordered service.

      Invention - The simplex connection is initiated by the source,
though sink endpoints may join after the connection is established.
A simplex connection is identified by a unique connection...