Detecting path break conditions while minimizing network overhead

1. A method for determining a break condition in a communication path by a receiving network appliance of a plurality of network appliances, the method comprising:

transmitting a first plurality of data packets for a data flow, by a transmitting network appliance to a receiving network appliance over a communication path;

receiving at the receiving network appliance, the first plurality of data packets for the data flow over the communication path;

determining that:

a first predetermined time interval has elapsed since a last data packet of the first plurality of data packets was received by the receiving network appliance over the communication path;

no data packets of any data flow have been received during the first predetermined time interval; and

no health probe packets have been received during the first predetermined time interval;

after expiration of the first predetermined time interval and during a second predetermined time interval:

determining by the transmitting network appliance that no data packets of any data flow have been transmitted from the transmitting network appliance to the receiving network appliance during the first predetermined time interval, and transmitting a plurality of health probe packets to the receiving network appliance;

expecting receipt at the receiving network appliance of either a data packet of a data flow, or a health probe packet of the plurality of health probe packets, during the second predetermined time interval;

determining, by the receiving network appliance, that:

the second predetermined time interval has elapsed;

no data packets of any data flow have been received during the second predetermined time interval; and

no health probe packets have been received during the second predetermined time interval; and

sending a message to the transmitting network appliance that there is likely a break condition in the communication path.

2. The method of claim 1 , wherein the first predetermined time interval can be dynamically adjusted by an administrator of the receiving network appliance.

3. The method of claim 1 , wherein the first predetermined time interval is less than one second.

4. The method of claim 1 , wherein the second predetermined time interval can be dynamically adjusted by an administrator of the receiving network appliance.

5. The method of claim 1 , wherein the second predetermined time interval is less than one second.

6. The method of claim 1 , wherein the message to the transmitting network appliance that there is likely a break condition in the communication path is sent over a different communication network than the communication network for the likely broken communication path.

7. The method of claim 1 , further comprising:

receiving at the transmitting network appliance, a message from the receiving network appliance that there is likely a break condition in the communication path;

ceasing to utilize the communication path for data transmission by the transmitting network appliance;

selecting another communication path for data transmission to the receiving network appliance based on network performance metrics; and

continuing to transmit data packets of the data flow over the other communication path.

8. The method of claim 1 , further comprising:

receiving at least one of a data packet of a data flow, or a health probe packet over the communication path, after expiration of the first predetermined time interval and expiration of the second predetermined time interval; and

sending a message to the transmitting network appliance that there is no longer a break condition in the communication path.

9. A method for determining a no-break condition in a communication path by a receiving network appliance of a plurality of network appliances, the method comprising:

transmitting a first plurality of data packets of a first data flow, by a transmitting network appliance to a receiving network appliance over a communication path;

receiving at the receiving network appliance, the first plurality of data packets of the first data flow over the communication path;

determining, at the receiving network appliance, that:

a first predetermined time interval has elapsed since a last data packet of the first plurality of data packets was received; and

no data packets of the first data flow, no data packets of a second data flow, or no health probe packets have been received during the first predetermined time interval;

after expiration of the first predetermined time interval, expecting receipt at the receiving network appliance of either a data packet of the first data flow, a data packet of the second data flow, or a health probe packet during a second predetermined time interval;

determining, at the receiving network appliance, that the second predetermined time interval has elapsed and at least one of a data packet of the first data flow, a data packet of the second data flow, or a health probe packet is received within the second predetermined time interval; and

receiving, at the receiving network appliance, a second plurality of data packets transmitted by the transmitting network appliance over the communication path.

10. The method of claim 9 , further comprising:

during the second predetermined time interval, after expiration of the first predetermined time interval, transmitting a plurality of health probe packets by the transmitting network appliance to the receiving network appliance.

11. The method of claim 7 , wherein the communication path and the other communication path are in different communication networks.

12. The method of claim 9 , wherein the first predetermined time interval can be dynamically adjusted by an administrator of the receiving network appliance.

13. The method of claim 9 , wherein at least one minute elapses between the receiving of the first plurality of data packets and the receiving of the second plurality of data packets.

14. The method of claim 9 , wherein the first predetermined time interval is less than one second.

15. The method of claim 9 , wherein the second predetermined time interval can be dynamically adjusted by an administrator of the receiving network appliance.

16. The method of claim 9 , wherein the second predetermined time interval is less than one second.

17. A method for enabling fast detection of a break condition in a communication path by a receiving network appliance of a plurality of network appliances, the method comprising:

transmitting, by a transmitting network appliance, a first plurality of data packets of a data flow to a receiving network appliance over a communication path;

determining, by the transmitting network appliance, that the transmission of the first plurality of data packets of the data flow has completed and the communication path is transitioning to an idle state;

waiting, by the transmitting network appliance, for the expiration of a first predetermined time interval; and

transmitting, by the transmitting network appliance, a plurality of fast health probes to the receiving network appliance during a second predetermined time interval.

18. The method of claim 17 , further comprising:

receiving the first plurality of data packets of the data flow by the receiving network appliance;

determining that the second predetermined time interval has elapsed and no expected fast health probes have been received by the receiving network appliance; and

sending a message from the receiving network appliance to the transmitting network appliance that there is likely a break condition in the communication path.

19. The method of claim 18 , further comprising:

receiving at least one data packet of a data flow, or a health probe packet over the communication path, after expiration of the first predetermined time interval and the second predetermined time interval; and

sending a message from the receiving network appliance to the transmitting network appliance that there is no longer a break condition in the communication path.