Allocated and dynamic bandwidth management

A communications switch providing integrated services to data cells transmitted therethrough, each data cell identified as belonging to one of multiple service classes, said switch having at least one input port in communication with an input communications link, at least one output port in communication with an output communications link, and a switch fabric therebetween, said switch comprising:

• an input processor, associated with each of said at least one input ports, for buffering, enqueuing and transmitting said data cells received from said input communications link according to a determination, made by said input processor, of whether allocated or dynamic intra-switch bandwidth may be utilized in transmitting said enqueued data cells across said switch fabric;
• a bandwidth arbiter, in communication with said at least one input processor, for arbitrating said dynamic intra-switch bandwidth among said input processors, and for tagging said data cells with a tag indicative of whether a respective data cell has been transmitted across said switch fabric utilizing said allocated or said dynamic intra-switch bandwidth;
• and
• an output processor, associated with each of said at least one output ports, for buffering and enqueuing said data cells transmitted by at least one of said input processors, tagged by said bandwidth arbiter, and received across said switch fabric, said output processor utilizing said bandwidth arbiter tag and data cell service class information in enqueuing said data cells for transmission to said output communications link in a prioritized manner.

A method of forwarding a data cell through a communications switch having an input port, an input processor associated with said input port, an output port, an output processor associated with said output port, a switch fabric disposed between said input port and said output port, and a bandwidth arbiter associated with said switch fabric, said method comprising the steps of:

• input buffering and enqueuing a data cell received at said input port by said input processor according to whether said data cell is to be forwarded, via said switch fabric, to said output port via allocated or dynamic intra-switch bandwidth;
• tagging said buffered and enqueued data cell by said bandwidth arbiter as a data cell to be forwarded over said switch fabric via said allocated or dynamic intra-switch bandwidth;
• forwarding said tagged data cell over said switch fabric by said input processor to said output processor;
• and
• output buffering and enqueuing said forwarded data cell, by said output processor at said output port, according to said tag, in a prioritized manner.