Browse Prior Art Database

Minimization of the IEEE 802.5 Token-Ring Architecture

IP.com Disclosure Number: IPCOM000118449D
Original Publication Date: 1997-Feb-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 4 page(s) / 118K

Publishing Venue

IBM

Related People

Noel, FE: AUTHOR [+3]

Abstract

Disclosed is a protocol reduction or minimization of the IEEE 802.5 Token-Ring MAC protocol. A station implementing the minimized protocol, so called minimized station, would be a fully operational station participating in the main-line shared media Token-Ring functions such as token passing, data transmission, and MAC frame processing, etc. The minimized station would have reduced complexity in the areas of error detection, fault isolation, and ring recovery. This complexity reduction facilitates the development of Token-Ring adapters for these minimized stations at a price point that approaches the lowest cost communication adapters. The minimized stations would be compatible with full 802.5 stations and network management but would not be standards compliant without further standards enhancement.

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Minimization of the IEEE 802.5 Token-Ring Architecture

      Disclosed is a protocol reduction or minimization of the IEEE
802.5 Token-Ring MAC protocol.  A station implementing the minimized
protocol, so called minimized station, would be a fully operational
station participating in the main-line shared media Token-Ring
functions such as token passing, data transmission, and MAC frame
processing, etc.  The minimized station would have reduced complexity
in the areas  of error detection, fault isolation, and ring recovery.
This complexity  reduction facilitates the development of Token-Ring
adapters for these  minimized stations at a price point that
approaches the lowest cost communication adapters.  The minimized
stations would be compatible with full 802.5 stations and network
management but would not be standards compliant without further
standards enhancement.

      The 802.5 standard defines all stations on a shared media
Token-Ring Local Area Network (LAN) segment as homogeneous.  In this
disclosure, we relax the assumption of homogeneity, such that the LAN
segment contains one or more full 802.5 station(s) along with
minimized or reduced stations.  The full 802.5 station(s) would
perform the error  detection, fault isolation, and ring recovery
using the existing 802.5  protocol.  The minimized stations would
monitor the ring recovery process  and would disconnect from the ring
if either (1) there was no operational  full 802.5 station on the LAN
segment or (2) the ring recovery was not  successfully completed
prior to the maximum time permitted.

      The minimized stations are less complex due to simplification
of the Finite State Machines (FSM) implemented in these stations.
The significant reduction in the monitor FSM for the minimized
station is shown in the Figure; states that are not needed in the
minimized monitor  FSM are crossed out, and states that remain or are
combined into a single  state are boxed.  The monitor FSM can be
minimized from the seven states  in the 802.5 standard to only two
states: the normal operation state and  the ring recovery state.

      The normal operation state corresponds to the REPEAT:M0 state
in the 802.5 standard.  The ring recovery state represents the
combined BEACON REPEAT:M5 and CLAIM TOKEN:M6 states.  The minimized
station will  not need any other monitoring states, since it will not
become the acti...