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Medium Access Protocol for Packet Switched High Speed Multi-channel Networks

IP.com Disclosure Number: IPCOM000110601D
Original Publication Date: 1992-Dec-01
Included in the Prior Art Database: 2005-Mar-25
Document File: 4 page(s) / 158K

Publishing Venue

IBM

Related People

Ramaswami, R: AUTHOR [+2]

Abstract

A media-access (MAC) protocol for broadcast multichannel packet-switched networks that (1) uses tunable transmitters and fixed-tuned receivers, (2) supports different traffic classes (connection-oriented with/without dedicated bandwidth and connectionless), (3) has low processing requirements, and (4) for a network of N stations, uses only N channnels is proposed. Previously proposed protocols have some but not all of the above properties.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 42% of the total text.

Medium Access Protocol for Packet Switched High Speed Multi-channel Networks

       A media-access (MAC) protocol for broadcast multichannel
packet-switched networks that (1) uses tunable transmitters and
fixed-tuned receivers, (2) supports different traffic classes
(connection-oriented with/without dedicated bandwidth and
connectionless), (3) has low processing requirements, and (4) for a
network of N stations, uses only N channnels is proposed.  Previously
proposed protocols have some but not all of the above properties.

      In any network where the underlying medium is broadcast, the
mechanism by which the users share the medium is called a
medium-access or MAC protocol.  The problem is to devise a MAC
protocol for high-speed multichannel networks that supports
packet-switching while
1.  Minimizing processing requirements.
2.  Making efficient use of the available bandwidth.
3.  Supporting different traffic classes.
4.  Minimizing the implementation cost.

      For a network of N stations there are N channels (wavelengths
for optical WDMA networks).  Each station is equipped with a receiver
that is fixed-tuned to one of these N channels (different from all
other stations) and a tunable transmitter (laser).  We will denote
the channel assigned to station A's receiver by gA (our emphasis is
on optical WDMA networks).  Thus, each  station can receive on one
and only one channel, and all stations wishing to transmit to a
particular station must co-ordinate their use of this channel.

      The data on each channel is divided into frames and each frame
is divided into slots.  Network-wide frame and slot synchronization
is assumed.

      It is assumed that there are three traffic classes:
1.  Connection-oriented with dedicated bandwidth.
2.  Connection-oriented without dedicated bandwidth.
3.  Connectionless.
Of then slots in each frame, n1 are to be used for Class 1 traffic,
n2 for Class 2 traffic, n3 for Class 3 traffic and nc for control.
Slot assignment and data transfer for different classes

      For a Class 1 connection from station A to station B, station B
assigns one (or more) of the n1 slots in each frame, on gB, to
station A for the duration of the connection.  (How this is done is
described later).  Station B may not assign this slot to any other
connection, and, therefore, other stations may not use this slot to
transmit to B.  Thus, the amount of bandwidth represented by this
slot(s) is dedicated to A for the duration of the connection.
Station A can send a packet to station B in this assigned slot on
channel gB .

      For a Class 2 connection from station A to station B, station B
assigns one (or more) of the n2 slots in each frame, on gB, to
station A for the duration of the connection; exactly as for a Class
1 connection.  However, station B may assign these slots to other
connections.  This time when station A sends a packet on its assigned
slot to B on gB, the packet wi...