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Bandwidth Allocation on Multiplex Loop

IP.com Disclosure Number: IPCOM000083534D
Original Publication Date: 1975-Jun-01
Included in the Prior Art Database: 2005-Mar-01
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Callahan, RW: AUTHOR [+2]

Abstract

A procedure is given below for dynamically allocating bandwidth on a time-divided loop, extending from a primary (host) station to a number of secondary stations (devices) and returning finally to the primary station.

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Bandwidth Allocation on Multiplex Loop

A procedure is given below for dynamically allocating bandwidth on a time- divided loop, extending from a primary (host) station to a number of secondary stations (devices) and returning finally to the primary station.

Typically, the primary sends a "cyclic" initiating signal delimiting an indeterminate series of time frames available for utilization by the secondaries. The secondaries "seize" these frames in accordance with a predetermined protocol and send message blocks to the primary. The problem presently addressed is to permit participation in each series by a maximum number of secondaries, without having device "overruns".

The procedure involves monitoring (e.g., at the primary station) current-loop load ("cycle" length) and minimum OF (overrun time factor) of all devices active (participating) currently. This information is used to control authorization of inactive devices to participate (become active).

Before starting an inactive "candidate" device, its known OF is compared to a loop load factor (B) capacity factor (C), and the minimum of all currently active devices, where: C = maximum loop capacity B = (Sigma BT+ Sigma OH) current + (delta BT+ delta OH) anticipated where BT = block transfer time (in frames), and (delta---) anticipated means the change anticipated if the candidate device participates; and OH = overhead of the particular loop protocol utilized.

If B exceeds C or the 0F of the candidate device to be...