Method and apparatus for interconnection of packet switches with guaranteed bandwidth

A network, comprising:

• a first set of QoS nodes communicatively coupled in a ring;
• and
• a second set of QoS nodes communicatively coupled with said first set to form a ring-star topology;
• wherein each QoS node includes a packet classifier to classify data packets based, at least in part, on a service level agreement (SLA) associated with each packet, a scheduler to order said packets for transmitting at or above a minimum data rate specified by an SLA associated with each packet, and a plurality of SLA queues, each corresponding to an SLA, wherein said scheduler orders said packets according to a deficit golden ratio algorithm.

A packet forwarding network device, comprising:

• an input to receive a plurality of data packets from one or more upstream nodes, each data packet including classification information;
• a classifier coupled with said input to associate each of said data packets with one of a plurality of service level agreements (SLAs) corresponding to said classification information;
• a scheduler responsive to said classifier to order said data packets for transmission such that said data packets are transmitted at or above a minimum data rate specified by their corresponding SLAs;
• a transmitter to transmit said data packets as ordered by said scheduler;
• and
• a congestion monitoring circuit coupled with said transmitter to monitor data packet transmission for data packets corresponding to each SLA, direct said transmitter to reduce a data rate of transmission of data packets for an SLA if downstream congestion is detected for data packets associated with said SLA, and direct said transmitter to maintain a data rate of transmission of data packets corresponding a different SLA for which downstream congestion is not detected.

An article of manufacture comprising a machine-accessible medium that includes content that when accessed provides instructions to cause a packet forwarding network device to:

• receive a plurality of data packets from one or more upstream nodes, each including classification information;
• classify each of said data packets with one of a plurality of service level agreements (SLAs) corresponding to said classification information for each packet;
• schedule said data packets for transmitting at or above a minimum data rate that corresponds to a respective SLA;
• and
• reduce a data rate for transmitting packets corresponding to an SLA if downstream congestion is detected for packets associated with said SLA and maintain a data rate for transmitting packets corresponding to a different SLA for which downstream congestion is not detected.

In a network switching node, a method comprising:

• receiving data packets, each data packet having a corresponding service level agreement (SLA);
• scheduling the data packets for transmitting at a data rate that is equal to or greater than a minimum data rate associated with the respective SLAs;
• and
• reducing the data rate for transmitting data packets corresponding to a particular SLA for which downstream congestion is detected wherein scheduling the data packets includes maintaining queues associated with one or more SLAs, placing the data packets into corresponding SLA queues, and multiplexing data packets from each SLA queue in accordance with a golden ration algorithm.

A network switching device, comprising:

• an input to receive a plurality of data packets from an upstream node, each data packet to correspond to a service level agreement (SLA);
• a scheduler to order the received data packets for transmission at a data rate equal to or greater than a minimum data rate associated with the corresponding SLAs;
• a transmitter to transmit the data packets downstream as ordered by the scheduler;
• and
• a congestion control circuit communicatively coupled with the transmitter and the downstream, to direct the transmitter to reduce the data rate of transmission of data packets corresponding to a particular SLA for which downstream congestion is detected.