Agile network protocol for secure communications with assured system availability

• US 6,618,761 B2
• Filed: 02/26/2002
• Issued: 09/09/2003
• Est. Priority Date: 10/30/1998
• Status: Expired due to Term

• Current Assignee: VirnetX Inc. (Virnetx Holding Corporation)
• Original Assignee: Science Applications International Corporation
• Inventors: Munger, Edmund Colby, Schmidt, Douglas Charles, Short, Robert Dunham, Larson, Victor, Williamson, Michael
• Primary Examiner(s): Lim, Krisna
• Application Number:
  US10/082,164
• Publication Number:
  US 20020161925A1
• Time in Patent Office: 560 Days
• Field of Search: 709/241, 709/238, 709/240, 709/242, 370/232, 370/237, 370/234, 370/448
• US Class Current: 709/241
• CPC Class Codes: H04L 2101/604 Address structures or formats
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/24 Multipath
• CPC Class Codes: H04L 45/243 using M+N parallel active paths
• CPC Class Codes: H04L 45/28 using route fault recovery
• CPC Class Codes: H04L 61/35 involving non-standard use of addresses for implementing network functionalities, e.g. coding subscription information within the address or functional addressing, i.e. assigning an address to a function
• CPC Class Codes: H04L 61/4511 using domain name system [DNS]
• CPC Class Codes: H04L 61/5007 Internet protocol [IP] addresses
• CPC Class Codes: H04L 61/5076 Update or notification mechanisms, e.g. DynDNS
• CPC Class Codes: H04L 61/5092 by self-assignment, e.g. picking addresses at random and testing if they are already in use
• CPC Class Codes: H04L 63/0272 Virtual private networks
• CPC Class Codes: H04L 63/0407 wherein the identity of one or more communicating identities is hidden cryptographic mechanisms or cryptographic arrangements for anonymous credentials or for identity based cryptographic systems H04L9/00
• CPC Class Codes: H04L 63/0414 during transmission, i.e. party's identity is protected against eavesdropping, e.g. by using temporary identifiers, but is known to the other party or parties involved in the communication
• CPC Class Codes: H04L 63/0428 wherein the data content is protected, e.g. by encrypting or encapsulating the payload
• CPC Class Codes: H04L 63/08 for authentication of entities cryptographic mechanisms or cryptographic arrangements for entity authentication H04L9/32
• CPC Class Codes: H04L 63/10 for controlling access to devices or network resources
• CPC Class Codes: H04L 63/1458 Denial of Service
• CPC Class Codes: H04L 63/1466 Active attacks involving interception, injection, modification, spoofing of data unit addresses, e.g. hijacking, packet injection or TCP sequence number attacks
• CPC Class Codes: H04L 63/1491 using deception as countermeasure, e.g. honeypots, honeynets, decoys or entrapment
• CPC Class Codes: H04L 65/403 Arrangements for multi-party communication, e.g. for conferences data switching systems for conference H04L12/18; arrangements for connecting several subscribers to a common circuit, i.e. affording conference facilities H04M3/56; television conferencing systems H04N7/15

Abstract

Methods and systems allowing a plurality of computer nodes to communicate using weighted transmission paths are provided. A load balancer distributes packets across weighted transmission paths according to transmission path quality, which is monitored and updated from time to time. As transmission quality on a specific transmission path decreases, the weight assigned to that transmission path is reduced. Similarly, weights may be increased if transmission quality improves. The weights assigned to various transmission paths may correspond to a relative number of packets to be transmitted on each respective transmission path. The transmission path for each packet can be selected based on the weights of the various transmission paths. Using weights based on transmission quality, transmission paths with higher transmission quality are used more often than transmission paths with lower transmission quality, resulting in more efficient communications.

Claims

1. A method of transmitting data packets, the method comprising the steps of:

(1) assigning a weight value to each of a plurality of transmission paths, wherein each respective weight value represents the relative number of packets that a respective transmission path will transmit;

(2) for each data packet that is to be transmitted from a first computer to a second computer, selecting one of the plurality of transmission paths on the basis of each respective transmission path'"'"'s assigned weight value;

(3) measuring a transmission quality for each of the plurality of transmission paths; and

(4) adjusting downwardly to a non-zero value the assigned weight value for a transmission path for which the transmission quality has declined.

2. The method of claim 1, wherein step (4) comprises the step of gradually decreasing over time the assigned weight value in relation to weight values assigned to the remaining transmission paths.

3. The method of claim 2, wherein step (4) comprises the step of gradually decreasing the assigned weight value according to an incrementally decreasing function.

4. The method of claim 2, wherein step (4) comprises the step of gradually decreasing the assigned weight value according to an exponentially decaying function.

5. The method of claim 1, wherein step (3) comprises the step of determining that one or more packets transmitted to the second computer was not acknowledged by the second computer.

6. The method of claim 1, wherein step (3) comprises the step of evaluating the contents of a synchronization packet that maintains synchronization with a moving window of valid values.

7. The method of claim 1, further comprising the step of inserting into each data packet a source and destination IP address pair that is selected according to a pseudo-random sequence.

8. The method of claim 1, wherein step (4) comprises the step of adjusting downwardly the assigned weight value for a transmission path only if the transmission quality has declined below a predetermined threshold.

9. The method of claim 1, further comprising the step of adjusting upwardly the assigned weight value that was adjusted in step (4) if it is later determined that the transmission quality has improved.

10. The method of claim 1, further comprising the step of adjusting upwardly the weight values of the remaining transmission links in an amount that compensates for the downwardly adjusted weight value.

11. The method of claim 10, wherein the step of adjusting upwardly comprises the step of equally distributing the amount that was downwardly adjusted across the remaining transmission links.

12. The method of claim 1, further comprising the step of adjusting downwardly to zero the assigned weight value for any transmission link whose quality has degraded below a preset threshold.

13. The method of claim 1, wherein steps (2) through (4) are repeated periodically.

14. A first computer that transmits data packets to a second computer over a plurality of separate transmission paths, wherein the first computer performs the steps of:

(1) assigning a weight value to each of the plurality of transmission paths, wherein each respective weight value represents the relative number of packets that a respective transmission path will transmit;

(2) for each data packet that is to be transmitted to the second computer, selecting one of the plurality of transmission paths on the basis of each respective transmission path'"'"'s assigned weight value;

(3) measuring the transmission quality for each of the plurality of transmission paths; and

(4) adjusting downwardly to a non-zero value the assigned weight value for a transmission path for which the transmission quality has declined.

15. The first computer of claim 14, wherein the first computer gradually decreases over time the assigned weight value in relation to weight values assigned to the remaining transmission paths.

16. The first computer of claim 15, wherein the first computer gradually decreases the assigned weight value according to an incrementally decreasing function.

17. The first computer of claim 15, wherein the first computer gradually decreases the assigned weight value according to an exponentially decaying function.

18. The first computer of claim 14, wherein the first computer measures the transmission quality by determining that one or more packets transmitted to the second computer was not acknowledged by the second computer.

19. The first computer of claim 14, wherein the first computer measures the transmission quality by evaluating the contents of a synchronization packet that maintains synchronization with a moving window of valid values.

20. The first computer of claim 14, wherein the first computer inserts into each data packet a source and destination IP address pair that is selected according to a pseudo-random sequence.

21. The first computer of claim 14, wherein the first computer adjusts downwardly the assigned weight value for any transmission path only if the transmission quality has declined below a predetermined threshold.

22. The first computer of claim 14, wherein the first computer adjusts upwardly the assigned weight value that was adjusted in step (4) if it is later determined that the transmission quality has improved.

23. The first computer of claim 14, wherein the first computer adjusts upwardly the weight values of the remaining transmission links in an amount that compensates for the downwardly adjusted weight value.

24. The first computer of claim 23, wherein the first computer upwardly adjusts probabilities across the remaining transmission links in an amount equal to the downwardly adjusted weight value.

25. The first computer of claim 14, wherein the first computer adjusts downwardly to zero the assigned weight value for any transmission link whose quality has degraded below a preset threshold.

26. The first computer of claim 14, wherein the first computer repeats steps (2) through (4) periodically.

27. A system comprising the first computer of claim 14 and a second computer constructed in accordance with the first computer of claim 14.