Browse Prior Art Database

Method for Generating Unique Communications Retry Period on Token Ring Network

IP.com Disclosure Number: IPCOM000104166D
Original Publication Date: 1993-Mar-01
Included in the Prior Art Database: 2005-Mar-18
Document File: 2 page(s) / 65K

Publishing Venue

IBM

Related People

Barrett, GV: AUTHOR [+4]

Abstract

A methodology is described which ensures Token Ring attached computers retry communications at a different time by calculating a unique retry time value according to the computer's Token Ring address.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Method for Generating Unique Communications Retry Period on Token Ring Network

      A methodology is described which ensures Token Ring attached
computers retry communications at a different time by calculating a
unique retry time value according to the computer's Token Ring
address.

      Token Ring (TR) Adapters have a unique address.  The TR adapter
address will be used for generating a unique sleep time so that retry
will have a greater chance of being successful in various
communications situations.  The TR adapter address is obtained from a
log file (e.g. OS/2* 1.3 ACSLAN.LOG) which is created when a computer
is rebooted or powered up.  The maximum number represented by 12
hexadecimal digits is never as large as 16**12 which is less than
3*(10**14).  Using the preferred embodiment of nanoseconds yields
(3*(10**14))/1000000000 = 300000 seconds which equals 300000/60 =
5000 minutes.  The preferred retry shall be maximized at 5 minutes.
Therefore 5000/1000 = a 5 minute period.  So, the figure constructed
from the Token Ring address must be divided by 1000 to span a 5
minute interval.

      In sum, a unique nanosecond number is generated from any Token
Ring address with the formula X = ((12 digit hexadecimal number) /
1000), such that X is in nanoseconds falling uniquely in an interval
0 to 5 minutes.

Examinating a number generation is explained with an example:

(It is important to note that TR addresses consist of 12 hexadecimal
digits (e.g., 10005A2BC7EB).

1.  Perform a left to right unsigned rotated shift on the TR address
    specified by the count equal to the sum of digits 1, 5, 9 and 12,
    respectively.

    10005A2BC7EB => 1+5+12+11 = 29 => shift 29 digits; ==>
    BC7EB10005A2

2.  Section the result from STEP 1 into six 2 digit unsigned parts....