公开(公告)号：DE3066854D1

公开(公告)日：1984-04-12

申请号：DE3066854

申请日：1980-10-15

Applicant: IBM

Inventor： LEE ROBERT POON-LUN ,  CLOSS FELIX H

IPC: H04L12/44 ,  H04L12/56 ,  H04Q5/00 ,  H04Q9/00 ,  H04L11/16

Abstract: A communication system for data packets comprises a multiplicity of nodal units inter-connected in an inverted tree hierarchy by a network of duplex data channels. Each unit (1, 20 or 22) comprises an up-port (33 min ) connected to another unit at a higher level or, in the case of the root nodal unit, via a loop line (3) back on itself. Each unit further comprises a plurality of down-ports connected to other nodal units (e.g. node 5) at lower levels or to terminal transceiver devices (e.g. port 40). The system operated for transmission up the hierarchy on a demand assignment basis whereby the demand detect logic (63, 65 or 67) which is first to detect incoming data, produces the first request signal RQ. This first request signal causes its own access control unit (57, 59 or 61) to provide a gating signal to its associated gate (51, 53 or 55) and an inhibit signal to the other access control unit. Data is broadcast downwardly, data arriving from a higher level is routed to all the next lower level nodes (2, 3 and 4).