Method for flow control in a packet switched network
View Patent ↗Efficient congestion control in a packet switched network is facilitated between at least one source and at least one destination. The source organizes known destinations, at above the link layer, into groups, each group containing one or more destinations. The group for each source packet may be identifiable by data natively present in the packet header. In some example, the source assigns an arbitrary identification to each group, and the source labels packets destined to a group with the identification for that group. A network node sends “PAUSE” packets containing at least one pause information indication back to a traffic source. The pause indication is associated with at least one group identification used by the source. The source reacts to the pause request by stopping or resuming packet transmission to the at least one group identification. Transmission to other destination groups is not affected.
1. A method to facilitate congestion control in a packet switched network comprising a plurality of nodes including a packet source node, the method comprising:
at the packet source node, maintaining a plurality of link-layer packet destination groups for each of at least some of a plurality of packets being provided, at above a link-layer, from the packet source node to destination nodes via at least one node of the network;
at the packet source node, receiving at least one pause packet from another node of the network, the pause packet indicating one of the packet destination groups; and
at the packet source node, moderating transmission, from the packet source node, of packets destined for a destination in the packet destination group indicated by the received pause packet,
wherein moderating transmission, from the packet source node, of packets destined for a destination in the packet destination group indicated by the received pause packet includes setting a particular non-zero rate of transmission, from the packet source node, of packets destined for a destination in the packet destination group indicated by the received pause packet.
2. The method of claim 1 , wherein:
at least one of the packets being provided from the packet source node to destinations nodes via nodes of the network include a label that is indicative of the packet destination group to which the destination of that packet belongs.
3. The method of claim 2 , wherein:
the label is a packet tag.
4. The method of claim 1 , wherein:
the other node, from which the pause packet is received, is a neighbor node of the packet source node.
5. The method of claim 1 , wherein:
the source node maintains a host routing table, and
maintaining a plurality of packet destination groups includes maintaining, in the host routing table, a correspondence of routes to packet destination groups.
6. The method of claim 1 , wherein, for at least some of the packet destinations,
the packet source node is aware of multiple paths to that packet destination; and
at least one of the paths to that packet destination is within a packet destination group that is different from a packet destination group for at least one other path to that packet destination.
7. A method to facilitate congestion control in a packet switched network comprising a plurality of nodes including a switch node, the method comprising:
by the switch node, determining that the network is congested with respect to traffic destined to at least one particular destination;
by the switch node, in response to the determination that the network is congested with respect to traffic destined to the at least one particular destination and based at least in part on a destination group indication in at least one first packet being routed by the switch including the at least one particular destination, providing a first pause packet to a source of the at least one first packet, the first pause packet including an indication of the destination group;
by the switch node, determining that the network is no longer congested with respect to traffic destined to the at least one particular destination; and
by the switch node, in response to the determination that the network is no longer congested with respect to traffic destined to the at least one particular destination, providing a second pause packet to the source of the at least one first packet, the second pause packet including an indication of the destination group.
8. A method to facilitate congestion control in a packet switched network comprising a plurality of nodes including a packet source node, the method comprising:
at the packet source node, maintaining a plurality of link-layer packet destination groups for each of at least some of a plurality of packets being provided, at above a link-layer, from the packet source node to destination nodes via at least one node of the network, wherein each link-layer packet destination group is indicative of a unique combination of at least one characteristic of the packets;
at the packet source node, receiving at least one pause packet from another node of the network, the pause packet indicating one of the link-layer packet destination groups; and
at the packet source node, moderating transmission, from the packet source node, of packets destined for a destination in the link-layer packet destination group indicated by the received pause packet,
wherein moderating transmission, from the packet source node, of packets destined for a destination in the packet destination group indicated by the received pause packet includes setting a particular non-zero rate of transmission, from the packet source node, of packets destined for a destination in the packet destination group indicated by the received pause packet.
9. The method of claim 8 , wherein:
the at least one characteristic includes, for packets to be formed by an offloading network interface controller (NIC), at least one of a Source MAC (SMAC) address index, a Destination MAC (DMAC) address index, a virtual NIC number, and a virtual interface number.
10. A method to facilitate congestion control in a packet switched network comprising a plurality of nodes including a packet source node, the method comprising:
by the switch node, determining that the network is congested with respect to packets having a particular destination;
by the switch node, in response to the determination that the network is congested with respect to packets having the particular destination, providing a first pause packet to a source of the at least one first packet, the first pause packet including an indication of a destination group to which the particular destination belongs;
by the switch node, determining that the network is no longer congested with respect to traffic destined to the at least one particular destination; and
by the switch node, in response to the determination that the network is no longer congested with respect to traffic destined to the at least one particular destination, providing a second pause packet to the source of the at least one first packet, the second pause packet including an indication of the destination group.
11. The method of claim 10 , wherein:
providing the first pause packet including the indication of the destination group to which the particular destination belongs includes determining the destination group based on an indication of the particular destination in at least one of the packets having the particular destination.
12. The method of claim 10 , wherein:
providing the first pause packet including the indication of the destination group to which the particular destination belongs includes determining the destination group based on an indication of the destination group in at least one of the packets having the particular destination.
13. A packet source network node device configured to operate in a packet-switched network including to facilitate congestion control in a packet switched network comprising a plurality of nodes including the packet source network node, the device configured to:
maintain a plurality of link-layer packet destination groups for each of at least some of a plurality of packets being provided, at above a link-layer, from the packet source node to destination nodes via at least one node of the network;
receive at least one pause packet from another node of the network, the pause packet indicating one of the packet destination groups; and
moderate transmission, from the packet source node, of packets destined for a destination in the packet destination group indicated by the received pause packet,
wherein moderating transmission, from the packet source node, of packets destined for a destination in the packet destination group indicated by the received pause packet includes setting a particular non-zero rate of transmission, from the packet source node, of packets destined for a destination in the packet destination group indicated by the received pause packet.
14. A switch node network device configured to operate in a packet switched network comprising a plurality of nodes including the switch node, the device configured to:
determine that the network is congested with respect to traffic destined to at least one particular destination;
in response to the determination that the network is congested with respect to traffic destined to at least one particular destination and based at least in part on a destination group indication in at least one first packet being routed by the switch including the at least one particular destination, provide a first pause packet to a source of the at least one first packet, the first pause packet including an indication of the destination group;
by the switch node, determining that the network is no longer congested with respect to traffic destined to the at least one particular destination; and
by the switch node, in response to the determination that the network is no longer congested with respect to traffic destined to the at least one particular destination, providing a second pause packet to the source of the at least one first packet, the second pause packet including an indication of the destination group.