Switching node with load balancing of bursts of packets

A method of controlling switching in a packet switching node, the node having a local input port for receiving packets belonging to a specified packet flow, to be sent on to a destination node, a burst assembler for assembling the received packets of that flow into bursts of packets, each burst having a burst control packet, the burst control packet indicating a sequence of the burst in the flow, to enable the sequence to be maintained after transmission, and a switch coupled to the local input port and to output ports, the method having the steps of:

• determining whether to distribute the flow;
• selecting, if the flow is to be distributed, at least two of the links to use for sending on the bursts of the flow towards the destination node;
• and
• distributing the bursts of the flow between the selected links by:
• forwarding a first of the bursts for switching to a first output port, for transmission over a first of the selected links;
• and
• forwarding a second of the bursts for switching to a second output port, for transmission over a second of the selected links according to the indicated sequence for the flow.

A method of operating a packet switching node coupled by links to other nodes, as an egress node, the method having the steps of:

• receiving at line input ports, bursts of packets belonging to a specified packet flow, sent over different links from another node, each burst having a burst control packet, the burst control packet indicating a sequence of the burst in the flow;
• selecting a local output port for packets of the flow;
• switching the bursts to the selected local output port;
• and
• ordering the packets of the bursts of a same flow, according to the indicated sequence.

A method of operating a packet switching node coupled by links to other nodes, as an intermediate node, the method having the steps of:

• receiving at line input ports, bursts of packets belonging to a specified packet flow, sent from another node, each burst having a burst control packet, the burst control packet indicating a sequence of the burst in the flow;
• determining if the flow is distributed;
• if not distributed, determining whether to distribute it over different links to different adjacent nodes;
• if distributed, determining whether to recombine it;
• if distributed and not to be recombined, selecting at least two of the links to use for sending on the bursts of the flow towards a destination node, and distributing the flow between the selected links by:
• forwarding a first of the bursts for switching to a first output port, for transmission over a first of the selected links;
• and
• forwarding a second of the bursts for switching to a second output port, for transmission over a second of the selected links according to the indicated sequence for the flow.

A packet switching node coupled by links to other nodes, the node having a local input port for receiving packets belonging to a specified packet flow, to be sent on to a destination node, a burst assembler for assembling the received packets of that flow into bursts of packets, each burst having a burst control packet, the burst control packet indicating a sequence of the bursts in the flow, to enable the sequence to be maintained after transmission, and a switch coupled to the local input port and to output ports, the node also having:

• a traffic controller being arranged to perform the following:
• selecting at least two of the links to use for sending on the bursts of this flow towards the destination node;
• and
• being coupled to the burst assembler to distribute the flow between the selected links by forwarding a first of the bursts from a first burst assembler queue to the switch for switching to a first output port, for transmission over a first of the selected links, and by forwarding a second of the bursts from a second burst assembler queue to the switch for switching to a second output port, for transmission over a second of the selected links.