Method for allocating a bandwidth between network terminals in a communication network and network including a medium access controller for performing such a method

A communication network including a main network station (LT) coupled to a plurality of network terminals (NTx), through a common link (L), and a medium access controller (MC) for bandwidth allocation between network terminals on the common link, said medium access controller including counters and stacks for allocating and forwarding permits to network terminals, each permit containing a terminal identifier and corresponding to a predetermined share of bandwidth, said medium access controller (MC) comprising:

• a guarantee counter (Gx) for each network terminals, with a determined guarantee increment (IncGx) and a determined guarantee maximum (MaxGx) for each guarantee counter, a guarantee stack (GS) for storing permits to be forwarded to the network terminals
• programmed means for defining permits according to the following first step:
• said first step including:
• updating the current value of each guarantee counter (Gx) by adding the corresponding guarantee increment (IncGx);
• stacking a permit in the guarantee stack (GS) and diminishing the current value of a guarantee counter (Gx) with the guarantee maximum (MaxGx), if this current value exceeds the guarantee maximum (MaxGx);
• said network being characterised in that the medium access controller also comprises:
• a fair counter (Fx) for each network terminal with a fair increment (IncFx) and a fair maximum (MaxFx) for each fair counter, and a fair stack (FS) for storing permits to be forwarded to the network terminals,
• programmed means for defining and forwarding permits by including also the following two steps:
• a second step by:
• updating the current value of each fair counter (Fx) by adding the corresponding increment (IncFx)
• stacking a permit in the fair stack (FS) and diminishing the current value of a fair counter (Fx) with the fair maximum (MaxFx), if this current value exceeds the fair maximum (MaxFx);
• a third step to forward a permit by:
• forwarding an idle permit, if the guarantee stack (GS) and the fair stack (FS) are both empty;
• extracting a permit from the fair stack (FS) and forwarding it, if the guarantee stack (GS) is empty and the fair stack (FS) is not empty;
• extracting a permit from the guarantee stack (GS) and forwarding it, if the guarantee stack (GS) is not empty.

A medium access controller for a communication network including a main network station (LT) coupled to a plurality of network terminals (NTx), through a common link (L), and a medium access controller (MC) for bandwidth allocation between network terminals on the common link, said medium access controller including counters and stacks for allocating and forwarding permits to network terminals, each permit containing a terminal identifier and corresponding to a predetermined share of bandwidth, said medium access controller (MC) comprising

• a guarantee counter (Gx) for each network terminal, with a determined guarantee increment (IncGx) and a determined guarantee maximum (MaxGx) for each guarantee counter, a guarantee stack (GS) for storing permits to be forwarded to the network terminals
• programmed means for defining permits according to the following first step:
• said first step including:
• updating the current value of each guarantee counter (Gx) by adding the corresponding guarantee increment (IncGx);
• stacking a permit in the guarantee stack (GS) and diminishing the current value of a guarantee counter (Gx) with the guarantee maximum (MaxGx), if this current value exceeds the guarantee maximum (MaxGx);
• said medium access controller being characterised in that it also comprises:
• a fair counter (Fx) for each network terminal with a fair increment (IncFx) and a fair maximum (MaxFx) for each fair counter, and a fair stack (FS) for storing permits to be forwarded to the network terminals,
• programmed means for defining and forwarding permits by including also the following steps:
• a second step by:
• updating the current value of each fair counter (Fx) by adding the corresponding increment (IncFx);
• stacking a permit in the fair stack (FS) and diminishing the current value of a fair counter (Fx) with the fair maximum (MaxFx), if this current value exceeds the fair maximum (MaxFx);
• a third step to forward a permit by:
• forwarding an idle permit, if the guarantee stack (GS) and the fair stack (FS) are both empty;
• extracting a permit from the fair stack (FS) and forwarding it, if the guarantee stack (GS) is empty and the fair stack (FS) is not empty;
• extracting a permit from the guarantee stack (GS) and forwarding it, if the guarantee stack (GS) is not empty.