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A Protocol for a Serial or Parallel Herribone Bus Link

IP.com Disclosure Number: IPCOM000044707D
Original Publication Date: 1984-Apr-01
Included in the Prior Art Database: 2005-Feb-06
Document File: 2 page(s) / 14K

Publishing Venue

IBM

Related People

Schick, T: AUTHOR

Abstract

This article describes a protocol for two-way transmission on a bus-herringbone network topology typical of CATV networks. A controller prepares and transmits a poll message indicating an order of solicitations to terminals or endpoints in a network. This poll message must pass all endpoints relating to the solicitation. The poll message is transmitted to any number of endpoints on a spur of the herringbone network. The poll message contains solicitations in the reverse order of the expected responses.

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A Protocol for a Serial or Parallel Herribone Bus Link

This article describes a protocol for two-way transmission on a bus- herringbone network topology typical of CATV networks. A controller prepares and transmits a poll message indicating an order of solicitations to terminals or endpoints in a network. This poll message must pass all endpoints relating to the solicitation. The poll message is transmitted to any number of endpoints on a spur of the herringbone network. The poll message contains solicitations in the reverse order of the expected responses.

Each endpoint solicited recognizes its identifier, and also records the identifier of the endpoint indicated in the poll message immediately following its identifier. Each solicited endpoint or terminal reads the inbound channel until it recognizes a packet from the endpoint identified in the poll message immediately following its own. When recognized, then the endpoint waits for the completion of that packet and then transmits its packet to the controller. In this manner all the solicited endpoints achieve access to the inbound channel without the concern for collision on the line.

In order to use this protocol, the following rules must be observed. The installation or network must appear as if it consists of simplex multipoint inbound and outbound links.

Each of the links is serial by bit, but could be serial by byte and permit bus, not ring attachment. The controller broadcasts outbound to the network with each parcel addressed to one or more destinations.

The terminal endpoints do not write on the outbound channel; only on the inbound channel after invited to do so.

One of the outbound broadcast message types sent by the controller could be a poll.

The controller determines a poll, which consists of several solicitations in a particular order.

The order of solicitations in the poll is the closest terminal endpoint, the first and the furthest last.

The controller may send periodic solicitations to terminal end points which are not currently in session to determine which may wish to become active.

The terminal endpoints wait to be solicited before accessing the inbound channel. The controller broadcasts the poll which includes a set of solicitations to a selected group of terminal endpoints, thereby inviting each to write their information on the inbound channel.

The set of solicitations determines the order the terminal endpoints are invite...