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Browse Prior Art Database

Media Sharing Among Local Area Networks

IP.com Disclosure Number: IPCOM000040255D
Original Publication Date: 1987-Oct-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 3 page(s) / 78K

Publishing Venue

IBM

Related People

Dorak, JJ: AUTHOR [+4]

Abstract

A technique is described whereby a programmable communications control adapter provides a means of sharing the media of local area networks (LANs). The concept eliminates the need to duplicate LAN wiring in a building, particularly when baseband or varying RF-MODEM carrier frequencies for broadband LANs are required. The adapter also has the ability to switch the shared LANs by means of LAN controller software initializations. In order to achieve media sharing there are two requirements for sharing the media among LANs; Conditioning and Monitoring. Conditioning - All nodes must be conditioned before transmission of data can occur.

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Media Sharing Among Local Area Networks

A technique is described whereby a programmable communications control adapter provides a means of sharing the media of local area networks (LANs). The concept eliminates the need to duplicate LAN wiring in a building, particularly when baseband or varying RF-MODEM carrier frequencies for broadband LANs are required. The adapter also has the ability to switch the shared LANs by means of LAN controller software initializations. In order to achieve media sharing there are two requirements for sharing the media among LANs; Conditioning and Monitoring. Conditioning - All nodes must be conditioned before transmission of

data can occur. Implementing carrier sense multiple

access/collision detect (CSMA/CD) LANs for the media

sharing provides that the transmit data path of any

station or node is connected to the receive circuits of

all stations or nodes, including the transmit node

itself. All the nodes continuously monitor the data

transition activities on the media. The node to

transmit data must wait until the media is unoccupied

before beginning transmission.

(Image Omitted)

The receive circuitry verifies its own transmitted data

to ensure that the data is valid. Should two nodes

transmit data at the same time, a data collision

occurs; therefore, the transmitting stations will

detect the mismatch between transmitted data and the

receive data and flag the processor that a

re-transmission must occur. Monitoring -

The receive circuit of all the nodes that connect to

the media will constantly monitor the data traffic on

the media. The valid data packet, from the media, must

be recognized by the receive circuit, and the

destination address of the packet received must

indicate that the packet is destined to the node,

before the packet can be f...