Patent ID: 6046983
Filing Date: 2000-04-04
Classification: H04L,H04Q

Abstract:
A dynamic rate control system which serves a plurality of terminals comprising:means for setting a virtual path for one of said terminals on the basis of a request from said one terminal;means for collecting route information which includes information relating to a residual bandwidth of the virtual path once said virtual path has been set up after a cell rate has been specified for said one terminal;means for holding the cell rate requested by said one terminal;means for controlling which, on the basis of the route information dynamically controls the cell rate of the virtual path once the virtual path has been set up, said control of said cell rate being provided so that said cell rate is as large as possible, up to the cell rate requested by said one terminal, and so that said cell rate is fair to the plurality of terminals from which there are connection requests;wherein the means for controlling comprises:notifying means for notifying information relating to an acceptable cell rate to source-side terminals of connections which said notifying means serves;means for collecting and holding various information relating to the plurality of connections which said collecting and holding means serves and which share a transmission link, said information comprising an allowed cell rate and an actual cell rate of each connection, a total bandwidth and a total input bandwidth of the shared transmission link, and a number of connections which share said transmission link; andmeans for calculating each connection, on the basis of the information held in said collecting and holding means, the allowed cell rate which the notifying means notifies to the source-side terminals;wherein the calculating means includes means for computing which uses a variance of the ratio of said allowed cell rate to the requested cell rate for each connection as an evaluative function, said variance being given by: ##EQU7## and obtains, for connection j (j=1, 2, . . . , n), the acceptable cell rate ERQ.sub.j at that switch by means of:ERQ.sub.j =ccr.sub.j -.alpha..sub.j .multidot.sign{n.multidot.ccr.sub.j /r.sub.j -w.multidot..SIGMA..sub.i ccr.sub.i /r.sub.i }where .SIGMA..sub.i and .SIGMA..sub.j are respectively the sums of from i=1 to i=n and from j=1 to j=n, ccr.sub.j and r.sub.j are respectively the allowed cell rate and the requested cell rate of connection j, n is the number of connections transmitting data, .alpha..sub.j and w are weighting functions, and sign { } is a function that indicates the sign of the value inside the curly brackets.