Apparatus for switching data in high-speed networks and method of operation

A communication network comprising a plurality of packet switches capable of transferring data in cells, wherein at least one of said packet switches comprises:

• N input ports capable of receiving and storing cells in a plurality of input queues;
• N output ports capable of receiving and storing cells from said N input ports in a plurality of output queues;
• a switch fabric for transferring said cells from said N input ports to said N output ports, said switch fabric comprising an internally buffered crossbar having N×N internal buffers associated therewith, wherein each internal buffer is associated with a crosspoint of one of said N input ports and one of said N output ports;
• and
• a scheduling controller capable of:
• selecting a first one of a plurality of queued head-of-line (HOL) cells from said input queues to be transmitted to a first one of said N×N internal buffers according to a fair queuing algorithm in which each of said queued HOL cells is allocated a weight of Rij ;
• and
• selecting a first one of a plurality of HOL cells buffered in a second one of said N×N internal buffers to be transmitted to a first one of said output queues according to the fair queuing algorithm in which each of said internally buffered HOL cells is allocated a weight of Rij;
• wherein a group of K queues share a combined capacity of 1, and
• ∑
• i
• =
• 1
• K
• ⁢
• R
• i
• ≤
• 1
• ,
• where Ri is a guaranteed bandwidth associated with queue i, wherein any queue being non-empty over a time interval T can be guaranteed a bandwidth of RiT+E, where E is a constant.

A packet switch, comprising:

• a plurality of input ports for receiving and storing cells in a plurality of input queues;
• a plurality of output ports for receiving and storing cells from the input ports in a plurality of output queues;
• a plurality of internal buffers, each internal buffer associated with one of the input ports and one of the output ports;
• and
• a scheduling controller for:
• selecting one of a plurality of queued head-of-line (HOL) cells from the input queues to be transmitted to a first one of the internal buffers according to a weight allocated to each of the queued HOL cells;
• and
• selecting on of a plurality of HOL cells buffered in a second one of the internal buffers to be transmitted to one of the output queues according to a weight allocated to each of the internally buffered HOL cells.

A method, comprising:

• receiving and storing cells in a plurality of input queues;
• transferring the cells from the input queues to a plurality of output queues using a plurality of internal buffers, each internal buffer associated with one of the input queues and one of the output queues;
• and
• receiving and storing the cells from the input queues in the plurality of output queues;
• receiving and storing the cells from the input queues in the plurality of output queues:
• wherein transferring the cells comprises:
• selecting one of a plurality of queued head-of-line (HOL) cells from the input queues to be transmitted to a first one of the internal buffers according to a weight allocated to each of the queued HOL cells;
• and
• selecting one of a plurality of HOL cells buffered in a second one of the internal buffers to be transmitted to one of the output queues according to a weight allocated to each of the internally buffered HOL cells.

A communication network comprising a plurality of packet switches, at least one of the packet switches comprising:

• a plurality of inputs ports capable of receiving and storing cells in a plurality of input queues;
• a plurality of output ports capable of receiving and storing cells from the input ports in a plurality of output queues;
• a plurality of internal buffers, each internal buffer associated with one of the input ports and one of the output ports;
• and
• a scheduling controller capable of:
• selecting one of a plurality of queued head-of-line (HOL) cells from the input queues to be transmitted to a first one of the internal buffers according to a weight allocated to each of the queued HOL cells;
• and
• selected one of a plurality of HOL cells buffered in a second one of the internal buffers to be transmitted to one of the output queues according to a weight allocated to each of the internally buffered HOL cells.