Browse Prior Art Database

Ring Utilization Measurement Device

IP.com Disclosure Number: IPCOM000039292D
Original Publication Date: 1987-May-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 3 page(s) / 52K

Publishing Venue

IBM

Related People

Barker, KJ: AUTHOR [+2]

Abstract

The article provides an apparatus and technique for measuring the utilization of a token ring LAN. Ring utilization is the fraction of time the ring is being used. It is calculated from the following expression: Ring utilization (RU) = 1-ring latency/available average token rate The technique expresses latency as the time between two consecutive free tokens and average available token rate as the time between free tokens. Thus, the apparatus simply measures the respective time and uses the result to calculate ring utilization. The figure shows a block diagram of the ring utilization measurement apparatus. It is connected to the token ring via a modified front end chip (MFEC) 1. The modified front end chip is a passive inductive connection to the token ring via a toroid through which the ring wire media passes.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 52% of the total text.

Page 1 of 3

Ring Utilization Measurement Device

The article provides an apparatus and technique for measuring the utilization of a token ring LAN. Ring utilization is the fraction of time the ring is being used. It is calculated from the following expression: Ring utilization (RU) = 1-ring latency/available average token rate The technique expresses latency as the time between two consecutive free tokens and average available token rate as the time between free tokens. Thus, the apparatus simply measures the respective time and uses the result to calculate ring utilization. The figure shows a block diagram of the ring utilization measurement apparatus. It is connected to the token ring via a modified front end chip (MFEC) 1. The modified front end chip is a passive inductive connection to the token ring via a toroid through which the ring wire media passes. The modified front end chip converts the analog ring signals obtained through the inductive connection to usable digital signals (Manchester encoded), and provides an 8 MHz clock (derived from the analog signals). The modified front end chip is constructed from a standard token ring adapter front end chip and a toroid. The timer circuit (TC) 2 contains a timer that can be reset, started, stopped, and the time value loaded into memory 4 under control of the main state machine (MSM) 3. The timer is derived from the 8 MHz clock obtained from the modified front end chip. The digitized ring signals and the 8 MHz clock outputted from the modified front end chip are fed to the main state machine. The main state machine determines if the digital patterns it receives from the modified front end chip are free or busy tokens. The stored time values are transmitted from memory 4 to host 5 for calculation of that ring utilization. The main state machine can operate in one of four modes. MODE ONE: When the main state machine detects a free token, it outputs a pulse to the timer circuit which causes the timer circuit to start the timer. If the next pattern that the main state machine detects is a busy token, the main state machine resets the timer, and waits to detect another free token. If the next pattern that the main state machine detects is a free token, the main state machine causes the timer counter to stop timing and places the time value T1 in the memory, resets and restarts the timer. The time value of T1 is equal to the ring latency. When the main state machine detects the next free token, it causes the timer circuit to stop timing and places the value T2 in the memory, resets and restarts the timer. This continues each time a free token is detected until the user stops this process or the memory is full. MODE TWO: When the main state machine detects a free token, it outputs a pulse to the timer circuit which ca...