Browse Prior Art Database

Implicit Token Passing Protocol

IP.com Disclosure Number: IPCOM000100395D
Original Publication Date: 1990-Apr-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 2 page(s) / 61K

Publishing Venue

IBM

Related People

Balakrishnan, M: AUTHOR [+2]

Abstract

Disclosed is a protocol that eliminates some of the delays associated with the passing of the token in token-passing broadcast networks.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 63% of the total text.

Implicit Token Passing Protocol

       Disclosed is a protocol that eliminates some of the
delays associated with the passing of the token in token-passing
broadcast networks.

      Establishing an order of transmission via token passing in
broadcast networks is an effective way of realizing a collision-free,
deterministic protocol.  But, in broadcast networks, unlike token
ring net works, every time the token is transmitted, the Phase-Locked
Loop (PLL) of each station must synchronize to the token
transmission.  This process may require many hundreds of bits, which,
when added to the transmission of the token itself, may result in
significant protocol overhead.  By contrast, the synchronization
overhead is not required in token ring networks because a station's
PLL is always locked-on to the transmission of exactly one station:
the one upstream to it.

      In an implicit token-passing protocol, both the token and the
token synchronization overhead are eliminated.  The implicit token-
passing protocol is shown in flowchart form in the figure and
involves the following steps:

      During an initialization period, each station is assigned an
address from 1 to M, where M is the total number of stations in the
network.  This address is used to initialize a counter at each
station, from hereon referred to as the "slot-counter".

      If the slot-counter at a station has the value of 1, the
station can proceed to transmit its message.  All other s...