Analysis of pipelined networks

• US 20030212926A1
• Filed: 05/10/2002
• Published: 11/13/2003
• Est. Priority Date: 05/10/2002
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Bhat, Thirumalesh, Wodrich, Mark, Cacka, Evan C.
• Granted Patent: US 6,993,683 B2
• Time in Patent Office: Days
• US Class Current: 714/43
• CPC Class Codes: H04L 1/22 using redundant apparatus to increase reliability
• CPC Class Codes: H04L 41/046 comprising network management agents or mobile agents therefor
• CPC Class Codes: H04L 41/0659 by isolating or reconfiguring faulty entities
• CPC Class Codes: H04L 43/06 Generation of reports
• CPC Class Codes: H04L 43/0823 Errors, e.g. transmission errors

Abstract

This invention relates to a diagnostic tool for networks that process messages in stages such as pipelined networks. In a pipelined network comprising tiers of servers, each tier of servers communicates only with adjacent tiers in a communications flow that processes messages in a sequence of tiers. The tool requires a controller located locally with respect to the pipelined network for generating messages to be processed by the pipelined network. Communication paths connect the controller to each tier of the pipelined network. A program executing at the controller detects a failure of the processing of the message by the pipelined network and receives diagnostic information from the tiers after the failure is detected. The diagnoses based on the retrieved information can proceed either manually or automatically, depending on how the information is collected. In order to automate the diagnosis, the program executing on the controller includes commands for sequentially analyzing each tier in the pipelined network in order to isolate the tier in which the failure occurred. For manual diagnosis, the program includes commands for simultaneously (or almost simultaneously) requesting information from each tier upon network failure. In the manual approach, distributed agents at all of the tiers gather information about the operating of the tier at the time of network failure.

Claims

1. A diagnostic tool in a pipelined network comprising tiers of servers wherein each tier of servers communicates only with adjacent tiers in a communications flow that processes messages in a sequence of the tiers, the tool comprising:

a controller located locally with respect to the pipelined network for generating a message to be processed by the pipelined network;

communication paths connecting the controller to each tier of the pipelined network; and

a program executing at the controller for detecting a failure of the processing of the message by the pipelined network and receiving diagnostic information from the tiers in the pipelined network after the failure is detected.

2. The diagnostic tool of claim 1 wherein the program includes commands responsive to the detection of the network failure for sequentially analyzing each tier in the pipelined network in order to isolate the tier in which the failure occurred.

3. The diagnostic tool of claim 1 wherein the program includes commands for substantially simultaneously requesting information from each tier upon network failure.

4. The diagnostic tool of claim 3 including distributed agents at all of the tiers that gather information about the operating of the tier at the time of network failure.

5. A method for diagnosing network failures in a pipelined server network comprising several tiers of processing a message, wherein each tier successively processes the message and forwards the message to the next tier, the method comprising:

detecting a failure of processing the message within the pipelined server network;

sequentially sending information to each processing tier of the pipelined server network, where the information simulates a proper processing of the message by a previous tier in the pipelined network; and

isolating the failure to the tier preceding the tier that receives the information and successfully replies.

6. The method of claim 5 wherein at least one of the tiers comprises several servers, each capable of processing the message as it is delivered from a previous tier.

7. The method of claim 6 wherein the several servers at said at least one of the tiers all receive the information.

8. The method of claim 5 wherein the pipelined server network is a remote access network.

9. The method of claim 8 wherein the remote access network is an authentication network comprising tiers of (1) remote access servers, (2) RADIUS proxy servers, (3) RADIUS servers and (4) domain controllers.

10. The method of claim 8 wherein the remote access network is an authentication network comprises tiers of (1) Remote Access Servers, (2) Internet Authentication Proxies, (3) Internet Authentication Servers and (4) Domain Controllers.

11. The method of claim 5 including the step of sending the message to a first tier of the pipelined server network via a virtual private network connection originating from within the pipelined server network.

12. The method of claim 9 wherein the information sent to a second tier of the pipelined server network comprises a remote authentication dial-up service authentication.

13. The method of claim 5 including the step of detecting the network failure by (1) sending information to one of the processing tiers of the pipelined server network;

(2) estimating a time interval between the sending of the information and a response; and

(3) isolating the failure to said one of the processing tiers if the time interval is greater than a maximum response time.

14. A method for diagnosing failures in a pipelined network comprising processing tiers wherein each tier communicates only with adjacent tiers in a communications flow that proceeds sequentially from one tier to another, said method comprising:

detecting a failure communicating a message through the tiers of the pipelined network;

automatically capturing data at each tier describing processing at the tier at the time of failure tailored to provide diagnostic information; and

analyzing the data to isolate the failure to one of the tiers.

15. The method of claim 14 including the step of orchestrating distributed agents resident at each of the tiers to capture the data at complementary time periods.

16. The method of claim 14 wherein the pipelined server network is a remote access network.

17. The method of claim 16 wherein the remote access network comprises remote access servers, RADIUS proxy servers, RADIUS servers and domain controllers.

18. The method of claim 17 wherein the data includes network packets, event log entries, and debug trace files.

19. The method of claim 14 including the step of receiving the data from each server in the pipelined server network.

20. The method of claim 14 wherein the captured data is data captured over a time interval and the step of analyzing the data includes (1) requesting the time interval data from a distributed agent on each server, (2) compiling the time interval data onto data files on each server;

and (3) sending the data files.

21. The method of claim 20 wherein automatically capturing data at each tier includes:

filtering network traffic; and

continuously capturing the filtered network traffic simultaneously into a file and into memory.

22. A computer-readable medium, having computer-executable instructions for diagnosing network errors in a pipelined network comprising tiers of servers wherein each tier of servers communicates only with adjacent tiers in a communications flow that processes messages in a sequence of the tiers, the computer-executable instructions performing steps comprising:

detecting a failure of the processing of a message by the pipelined network;

communicating directly with each tier of the pipelined network through a local communication path; and

retrieving diagnostic information from the tiers in the pipelined network after the failure is detected.

23. The computer-readable medium of claim 22, wherein the computer-executable instructions for retrieving diagnostic information further comprise computer-executable instructions for sequentially analyzing each tier in the pipelined network in order to isolate the tier in which the failure occurred.

24. The computer-readable medium of claim 22, wherein the computer-executable instructions for retrieving diagnostic information further comprise computer-executable instructions for substantially simultaneously retrieving diagnostic information from each tier upon failure.

25. A computer-readable medium, having computer-executable instructions for diagnosing network failures in a pipelined server network comprising several tiers of processing a message, wherein each tier successively processes the message and forwards the message to the next tier, the computer-executable instructions performing steps comprising:

detecting a failure of processing the message within the pipelined server network; and

sequentially sending information to each processing tier of the pipelined server network, where the information simulates a proper processing of the message by a previous tier in the pipelined network.

26. A computer-readable medium, having computer-executable instructions for diagnosing failures in a pipelined network comprising processing tiers wherein each tier communicates only with adjacent tiers in a communication flow that proceeds sequentially from one tier to another, the computer-executable instructions performing steps comprising:

detecting a failure communicating a message through the tiers of the pipelined network; and

retrieving data automatically captured at each tier describing processing at the tier at the time of failure, said data tailored to provide diagnostic information.

27. The computer-readable medium of claim 26, wherein the computer-executable instructions for retrieving data automatically captured at each tier further comprise computer-executable instructions for interacting with distributed agents resident at each of the tiers to capture the data at complementary time periods.