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Unsolicited Return of a Set Initial Program Load in a Closed-Ring Environment

IP.com Disclosure Number: IPCOM000047159D
Original Publication Date: 1983-Oct-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 47K

Publishing Venue

IBM

Related People

Lanier, CS: AUTHOR [+4]

Abstract

When data processing stations intercommunicate with each other in multi-accessible networks (rings, loops, star networks, etc.), certain communications create possibilities for contention and error. For example, a station may transmit a request message frame in a broadcast mode soliciting service from any listening station (e.g., initial program load (IPL) action) and then receive non-responsive frames requiring processing attention which may delay or block the completion of the required service. Furthermore, the requesting station may receive positive responses from more than one station representing a contention which must be resolved (for example, responses indicating initiation of IPL action by two or more contending sources). These conflicts and contentions can be avoided by using the following protocols.

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Unsolicited Return of a Set Initial Program Load in a Closed-Ring Environment

When data processing stations intercommunicate with each other in multi-accessible networks (rings, loops, star networks, etc.), certain communications create possibilities for contention and error.

For example, a station may transmit a request message frame in a broadcast mode soliciting service from any listening station (e.g., initial program load (IPL) action) and then receive non-responsive frames requiring processing attention which may delay or block the completion of the required service. Furthermore, the requesting station may receive positive responses from more than one station representing a contention which must be resolved (for example, responses indicating initiation of IPL action by two or more contending sources). These conflicts and contentions can be avoided by using the following protocols. When issuing a request message which requires urgent attention the source station may set itself to a selective receiving mode in which it becomes receptive only to a message containing information (desirably in the preamble or introductory portion of the message) indicating a response association to the original request message. All other messages are returned to the senders marked either as "unsolicited" or "refused".

Upon receiving a first positive response, the requesting station sets itself to a second selective reception mode in which it will receive data frames thereafter only from the originator of the response (e.g., frames of IPL data), and reject responses and data frames from all other sources. Fig. 1 shows an eight-node ring with duplicate ...