Network connectivity determination based on passive analysis of connection-oriented path information

• US 8,160,062 B2
• Filed: 02/05/2007
• Issued: 04/17/2012
• Est. Priority Date: 01/31/2006
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Qian, Tin, Talbut, James
• Primary Examiner(s): PHAN, MAN U
• Application Number:
  US11/702,478
• Publication Number:
  US 20070177524A1
• Time in Patent Office: 1,898 Days
• Field of Search: 370252-395, 370216-241, 370412-474, 370/250, 709200-250
• US Class Current: 370/389
• CPC Class Codes: H04J 1/16 Monitoring arrangements for transmission in general H04B17/00; for amplifiers H03F1/52, H03F1/523
• CPC Class Codes: H04J 3/16 in which the time allocation to individual channels within a transmission cycle is variable, e.g. to accommodate varying complexity of signals, to vary number of channels transmitted H04J3/17, H04J3/24 take precedence
• CPC Class Codes: H04L 43/0811 by checking connectivity
• CPC Class Codes: H04L 43/12 Network monitoring probes
• CPC Class Codes: H04L 69/16 Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]

Abstract

Passive analysis connection detection architecture that leverages connection-oriented end-to-end stack protocol information. In a TCP/IP implementation, by passively leveraging TCP information, a given system can determine in a more realtime fashion the connectivity state of a TCP pathway. Additionally, other passive information from the TCP/IP stack such as send/receive packet counts can be considered. Based on analysis of TCP path information and/or send/receive packet counts, loss of certain network connectivity can be inferred, which greatly improves the accuracy and responsiveness of detecting network connectivity losses. The disclosed architecture also facilitates improved performance when using proxy systems for network connectivity so as to reduce unnecessary network traffic and to route network systems to other online systems in a more efficient and effective manner.

Claims

1. A computer-implemented system for determining network connectivity, comprising:

a stack component configured to obtain connection-oriented path information from a protocol stack associated with a client;

an analysis component configured to compute a state of a connection based at least in part on the path information;

a state component configured to transition the state of the connection, the transitioning comprising at least one of;

transitioning from a first reachable state to a second suspect state; and

transitioning from a first suspect state to a second reachable state; and

a learning and reasoning component configured to employ at least one of a probabilistic and statistical-based analysis to at least one of prognose or infer an action desired to be performed.

2. The system of claim 1, the connection-oriented path information based at least in part on transmission control protocol (TCP).

3. The system of claim 1, the path information representing a connectivity state related to at least one of a reachable, unreachable, or cannot reach state of the connection.

4. The system of claim 1, the analysis component configured to analyze count information related to at least one of a send packet or a receive packet.

9. The system of claim 1, comprising a routing component configured to switch connectivity to another system based at least in part on the computed state.

10. The system of claim 1, the path information of the client related to connectivity to a proxy server.

11. The system of claim 1, comprising transitioning from at least one of the suspect states based at least in part on a highest level of observed packets during at least one of the suspect states.

5. A computer-implemented system for determining network connectivity, comprising:

a stack component configured to obtain connection-oriented path information from a protocol stack associated with a client;

an analysis component configured to compute a state of a connection based at least in part on the path information; and

a state component configured to transform the state of the connection between a suspect state and a connectivity state and expire the suspect state after a predetermined period of time elapses and the suspect state has not been cancelled.

6. The system of claim 5, the state component configured to automatically transition back to the connectivity state after a predetermined amount of time expires when in the suspect state.

7. The system of claim 5, the analysis component configured to initiate probing to determine the state of the connection when no packets have been observed during the suspect state.

8. The system of claim 5, the state component configured to transition from the suspect state based at least in part on a highest level of observed packets during the suspect state.

12. A computer-implemented method of determining network connectivity, comprising:

accessing connection-oriented end-to-end path information of a protocol stack of a connection;

analyzing the path information to determine a condition of the connection;

transitioning between a connectivity state and a suspect state based at least in part on the condition, comprising transitioning from the suspect state based at least in part on received packets that indicate an equivalent or higher connectivity level than a level associated with the suspect state; and

transitioning from the suspect state based at least in part on a highest level of observed packets during the suspect state, the connectivity state associated with the highest level of at least some of the observed packets.

13. The method of claim 12, comprising transitioning to the suspect state based at least in part on new unreachable path information or new cannot reach path information.

14. The method of claim 12, comprising transitioning to the suspect state based at least in part on an increase in a packet send count with no corresponding increase in a packet receive count.

15. The method of claim 12, comprising expiring the suspect state after a predetermined period of time elapses and the suspect state has not been cancelled.

16. The method of claim 12, the transitioning between a connectivity state and a suspect state comprising transitioning from a reachable state to a suspect state until a state of the connection allows transitioning back to the reachable state.

17. The method of claim 12, comprising transitioning from the suspect state based at least in part on new reachable path information, if a transition to the suspect state was based at least in part on unreachable or cannot-reach path information.

18. The method of claim 12, comprising transitioning from an Internet connectivity state to the suspect state based on paths to non-local remote hosts.

19. The method of claim 12, comprising confirming the connectivity state to a proxy server of a network environment based at least in part on new reachable path information to the proxy server.

20. A computer-implemented system, comprising:

computer-implemented means for accessing connection-oriented end-to-end path information of a protocol stack of a connection;

computer-implemented means for analyzing the path information to determine a condition of the connection and compute a state of the connection; and

computer-implemented means for transitioning the state of the connection between a connectivity state and a suspect state based at least in part on at least one of the condition or a highest level of observed packets during the suspect state, the connectivity state associated with the highest level of at least some of the observed packets.