Packet load shedding
View Patent ↗Methods, apparatuses and systems directed to enhanced packet load shedding mechanisms implemented in various network devices. In one implementation, the present invention enables a selective load shedding mechanism that intelligently discards packets to allow or facilitate management access during DoS attacks or other high traffic events. In one implementation, the present invention is directed to a selective load shedding mechanism that, while shedding load necessary to allow a network device to operate appropriately, does not attempt to control traffic flows, which allows for other processes to process, classify, diagnose and/or monitor network traffic during high traffic volume periods. In another implementation, the present invention provides a packet load shedding mechanism that reduces the consumption of system resources during periods of high network traffic volume.
1. An apparatus operative to shed packet load, comprising
a system bus,
a processor connected to the system bus;
a system memory, connected to the system bus, wherein the system memory maintains a plurality of data structures, the plurality of data structures comprising
a packet buffer for storing packets;
at least one network interface receive ring for storing pointers to packets in the packet buffer; and
at least one receive queue for storing pointers to packets in the packet buffer;
at least one network interface, connected to the system bus, operative to
receive packets transmitted over a computer network;
store received packets in the packet buffer, and
maintain pointers to the received packets in a corresponding one of the network interface receive rings; and
discard packets transmitted over the computer network when the corresponding network interface receive ring is full; and
a network interface driver operative to
read a limited number of packet pointers from the at least one network interface receive ring to the receive queue based on a read limit corresponding to the at least one network interface;
wherein the apparatus is further operative to
adjust the read limit for at least one of the at least one network interfaces based on observed aggregate packet load across the at least one network interfaces.
2. The apparatus of claim 1 wherein the network interface is operative to directly access the system memory over the system bus to store packets in the packet buffer and maintain packet pointers in the network interface receive ring.
3. The apparatus of claim 1 further comprising
an interrupt timer operative to transmit interrupt signals at periodic intervals; and
an interrupt controller operative to dedicate system resources to the network interface driver upon receipt of the interrupt signals.
4. The apparatus of claim 1 wherein the read limit for the at least one network interface is initially set based on the packet load capacity of the apparatus.
5. The apparatus of claim 4 wherein the packet load capacity is defined as a number of packets per periodic interval.
6. The apparatus of claim 4 wherein the apparatus is operative to decrease the read limit for a selected network interface if the aggregate packet load exceeds the packet load capacity of the apparatus.
7. The apparatus of claim 6 wherein the apparatus is operative to increase the read limit for a selected network interface if the aggregate packet load does not exceed the packet load capacity of the apparatus.
8. The apparatus of claim 7 wherein the packet load at the at least one network interface is based on the number of packet pointers read into the receive ring during a given periodic interval.
9. The apparatus of claim 8 wherein the apparatus is operative to select the most heavily loaded interface when decreasing the corresponding read limit.
10. The apparatus of claim 9 wherein the apparatus is operative to select the interface whose packet load equals the corresponding read limit when increasing the corresponding read limit.
11. The apparatus of claim 1 wherein the network interface driver is operative to read a limited number of packet pointers, at periodic intervals, from the at least one network interface receive ring to the receive queue based on the read limit corresponding to the at least one network interface.