WLAN diagnostics using traffic stream metrics

• US 8,005,030 B2
• Filed: 12/30/2005
• Issued: 08/23/2011
• Est. Priority Date: 12/30/2005
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Huang, Wenfeng, Kim, Jason, Bilstad, Arnold Mark, Stephenson, David Sheldon
• Primary Examiner(s): Afshar; Kamran
• Assistant Examiner(s): Zewari; Sayed T
• Application Number:
  US11/322,749
• Publication Number:
  US 20080253314A1
• Time in Patent Office: 2,062 Days
• Field of Search: 370310-350
• US Class Current: 370/310
• CPC Class Codes: H04B 17/26 using historical data, averaging values or statistics
• CPC Class Codes: H04W 24/08 Testing, supervising or monitoring using real traffic
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

Methods, apparatuses and systems directed to facilitating WLAN diagnostics and management using traffic stream metrics. In a data collection stage, according to one implementation of the present invention, localized uplink measurements are taken at a wireless client associated with a wireless access point. During periodic intervals (e.g., every 5 seconds), the wireless client, in one implementation, transmits uplink measurement information to the wireless access point. The wireless access point may also take downlink measurements, which may also include one or more of the following metrics: observed latency, queuing delay, packet loss rate, and packet count information. The wireless access point, in one implementation, may aggregate and report the uplink and downlink metric information to a network management system. In a diagnostic stage, according to one implementation, a wireless network management module performs diagnostics of the WLAN based on the uplink and/or downlink metrics received from the wireless access-point.

Claims

1. A wireless client operative to communicate with a wireless access point in a wireless network, the wireless client comprising:

one or more processors;

a memory;

a network interface; and

a wireless network driver application, physically stored in the memory, comprising instructions that, when executed by the one or more processors, cause the wireless client to;

monitor transmission of one or more frames between the wireless client and a wireless access point at a Medium Access Control (MAC) layer;

collect uplink metric data based on the transmission of the one or more frames the uplink metric data comprising one or more uplink latencies of the one or more frames;

construct an uplink latency histogram that comprises a count for each of a plurality of defined latency intervals using the one or more uplink latencies, comprising;

maintaining counts of respective numbers of the one or more uplink latencies that fall within each of the plurality of defined latency intervals;

generate a report message including the uplink latency histogram and at least some of the uplink metric data; and

transmit the report message to the wireless access point.

2. The wireless client of claim 1, wherein the uplink metric data further comprises one or more of latency, queuing delay, packet loss rate, packet count, roam count, and roam time.

3. The wireless client of claim 2, wherein, to collect latency data, the wireless network driver application further comprises instructions that, when executed by the one or more processors, cause the wireless client to:

receive a frame in a transmit queue;

transmit the frame to the wireless access point;

generate a time stamp for the frame;

receive, from the wireless access point, an acknowledgment;

compute the latency data based on the difference between the arrival time of the acknowledgment and the generated time stamp; and

increment the count in the latency histogram for the latency interval in which the computed latency data belongs.

4. The wireless client of claim 3 wherein, to collect packet loss rate data, the wireless network driver application further comprises instructions that, when executed by the one or more processors, cause the wireless client to:

detect transmission failures between the wireless client and the wireless access point;

if a transmission failure occurs, log the transmission failure; and

store packet loss rate data.

5. The wireless client of claim 2 wherein, to collect roam time data, the wireless network driver application further comprises instructions that, when executed by the one or more processors, cause the wireless client to:

upon initiation of a roam event from a first wireless access point to a second wireless access point, detect the time difference between receipt of the last frame from the first wireless access point and receipt of the first frame from the second access point to compute a roam time.

6. In a wireless client operative to communicate with a wireless access point in a wireless network, a method comprising:

monitoring transmission of one or more frames between the wireless client and a wireless access point at a Medium Access Control (MAC) layer;

collecting uplink metric data based on the transmission of the one or more frames the uplink metric data comprising one or more uplink latencies of the one or more frames;

constructing an uplink latency histogram that comprises a count for each of a plurality of defined latency intervals using the one or more uplink latencies, comprising;

maintaining counts of respective numbers of the one or more uplink latencies that fall within each of the plurality of defined latency intervals;

generating a report message including the uplink latency histogram and at least some of the uplink metric data; and

transmitting the report message to the wireless access point.

7. The method of claim 6, wherein the uplink metric data further comprises one or more of latency, queuing delay, packet loss rate, packet count, roam count, and roam time.

8. The method of claim 7, wherein collecting latency data further comprises:

receiving a frame in a transmit queue;

transmitting the frame to the wireless access point;

generating a time stamp for the frame;

receiving, from the wireless access point, an acknowledgment;

computing the latency data based on the difference between the arrival time of the acknowledgment and the generated time stamp; and

incrementing the count in the latency histogram for the latency interval in which the computed latency data belongs.

9. The method of claim 8 wherein collecting packet loss rate data further comprises:

detecting transmission failures between the wireless client and the wireless access point; and

if a transmission failure occurs, logging the transmission failure; and

storing packet loss rate data.

10. The method of claim 7 wherein collecting roam time data further comprises:

upon initiation of a roam event from a first wireless access point to a second wireless access point, detecting the time difference between receipt of the last frame from the first wireless access point and receipt of the first frame from the second access point to compute a roam time.

11. A wireless client operative to communicate with a wireless access point in a wireless network, the wireless client comprising:

means for monitoring transmission of one or more frames between the wireless client and a wireless access point at a Medium Access Control (MAC) layer;

means for collecting uplink metric data based on the transmission of the one or more frames the uplink metric data comprising one or more uplink latencies of the one or more frames;

means for constructing an uplink latency histogram that comprises a count for each of a plurality of defined latency intervals using the one or more uplink latencies, comprising;

means for maintaining counts of respective numbers of the one or more uplink latencies that fall within each of the plurality of defined latency intervals;

means for generating a report message including the uplink latency histogram and at least some of the uplink metric data; and

means for transmitting the report message to the wireless access point.

12. A wireless access point operative to wirelessly communicate with a wireless client and to communicate with a wireless network management server in a wireless network, the wireless access point comprising:

one or more wireless network interfaces for communication with one or more wireless clients;

one or more processors;

a memory;

a network interface; and

a wireless access point application, physically stored in the memory, comprising instructions that, when executed by the one or more processors, cause the wireless access point to;

receive from the wireless client a plurality of reports, each of the plurality of reports comprising an uplink latency histogram and uplink metric data, wherein the uplink latency histogram comprises a plurality of counts corresponding to a plurality of latency intervals, wherein each of the plurality of counts indicates a number of uplink latencies that fall within one of the plurality of latency intervals;

aggregate the uplink latency histograms and the uplink metric data in the plurality of reports; and

transmit, from the wireless access point to the wireless network management server, a report comprising the aggregated uplink latency histogram and uplink metric data.

13. The wireless access point of claim 12 wherein the wireless access point application further comprises instructions that, when executed by the one or more processors, cause the wireless access point to:

update a packet loss counter; and

update a maximum packet loss counter.

14. The wireless access point of claim 12 wherein the wireless access point application further comprises instructions that, when executed by the one or more processors, cause the wireless access point to:

monitor transmission of one or more frames between the wireless access point and the wireless client;

collect downlink metric data based on the transmission of the one or more frames, the downlink metric data comprising one or more downlink latencies of the one or more frames;

construct a downlink latency histogram that comprises a count for each of a plurality of latency intervals using the one or more downlink latencies; and

transmit, to the wireless network management server, a report comprising the downlink latency histogram and at least some of the downlink metric data.

15. The wireless access point of claim 14 wherein the downlink metric data comprises one or more of observed latency, observed queuing delay, observed packet loss rate, and packet drop count.

16. In a wireless access point operative to wirelessly communicate with a wireless client and to communicate with a wireless network management server in a wireless network, a method comprising:

receiving from the wireless client a plurality of report, each of the plurality of reports comprising an uplink latency histogram and uplink metric data, wherein the uplink latency histogram comprises a plurality of counts corresponding to a plurality of latency intervals, wherein each of the plurality of counts indicates a number of uplink latencies that fall within one of the plurality of latency intervals;

aggregating the uplink latency histograms and the uplink metric data in the plurality of reports; and

transmitting, from the wireless access point to the wireless network management server, a report comprising the aggregated uplink latency histogram and uplink metric data.

17. The method of claim 16 further comprising:

updating a packet loss counter; and

updating a maximum packet loss counter.

18. The method of claim 16 further comprising:

monitoring transmission of one or more frames between the wireless access point and the wireless client;

collecting downlink metric data based on the transmission of the one or more frames, the downlink metric data comprising one or more downlink latencies of the one or more frames;

constructing a downlink latency histogram that comprises a count for each of a plurality of latency intervals using the one or more downlink latencies; and

transmitting, to the wireless network management server, a report comprising the downlink latency histogram and at least some of the downlink metric data.

19. The method of claim 18 wherein the downlink metric data comprises one or more of observed latency, observed queuing delay, observed packet loss rate, and packet drop count.

20. A wireless access point operative to wirelessly communicate with a wireless client and to communication with a wireless network management server in a wireless network, the wireless access point comprising:

means for receiving from the wireless client a plurality of reports, each of the plurality of reports comprising an uplink latency histogram and uplink metric data, wherein the uplink latency histogram comprises a plurality of counts corresponding to a plurality of latency intervals, wherein each of the plurality of counts indicates a number of uplink latencies that fall within one of the plurality of latency intervals;

means for aggregating the uplink latency histograms and the uplink metric data in the plurality of reports; and

means for transmitting, from the wireless access point to the wireless network management server, a report comprising the aggregated uplink latency histogram and uplink metric data.

21. A wireless network management server operative to communicate with a wireless access point in a wireless network, the wireless network management server comprising:

one or more processors;

a memory;

a network interface; and

a management application, physically stored in the memory, comprising instructions that, when executed by the one or more processors, cause the wireless network management server to;

receive a report message comprising an uplink latency histogram or a downlink histogram and at least one of uplink and downlink metric data generated by one or more nodes of a wireless network;

analyze the report messages to determine at least one metric or fault associated with the wireless network, comprising compute jitter using the uplink latency histogram or the downlink histogram; and

construct a fault flowchart for the wireless network based on the analysis, wherein for each of the at least one fault determined during the analysis to be associated with the wireless network, the fault flowchart indicates a type and a cause of the fault.

22. The wireless network management server of claim 21, wherein the management application further comprises instructions that, when executed by the one or more processors, cause the wireless network management server to:

isolate a problem to a wireless access point based on the downlink metric data.

23. The wireless network management server of claim 21, wherein the management application further comprises instructions that, when executed by the one or more processors, cause the wireless network management server to:

determine whether the wireless network is operating with correct operational parameters relative to quality of service (QoS).

24. The wireless network management server of claim 21, wherein the management application further comprises instructions that, when executed by the one or more processors, cause the wireless network management server to perform at least one of:

output a recommendation for one or more remedial measures; and

automatically perform at least one of the remedial measures.

25. The wireless network management server of claim 24, wherein the recommendation comprises information for a network administrator, and wherein the information enables the network administrator to further diagnose problems in the wireless network.

26. The wireless management network server of claim 24, wherein the remedial measures comprise increasing the minimum contention window size setting (CWmin) or the arbitration interframe space (AIFS) for the best-effort and background data queues at the wireless access point.

27. The wireless management network server of claim 24, wherein the remedial measures comprise reducing the CCA and SOP sensitivity of both the wireless access point and wireless clients wireless PHYs.

28. In a wireless network management server operative to communicate with a wireless access point in a wireless network, a method comprising:

receiving a report message comprising an uplink latency histogram or a downlink histogram and at least one of uplink and downlink metric data generated by one or more nodes of a wireless network;

analyzing the report messages to determine at least one metric or fault associated with the wireless network, comprising computing jitter using the uplink latency histogram or the downlink histogram; and

constructing a fault flowchart for the wireless network based on the analysis, wherein for each of the at least one fault determined during the analysis to be associated with the wireless network, the fault flowchart indicates a type and a cause of the fault.

29. The method of claim 28 further comprising

isolating a problem to a wireless access point based on the downlink metric data.

30. The method of claim 28 further comprising

determining whether the wireless network is operating with correct operational parameters relative to quality of service (QoS).

31. The method of claim 28 further comprising at least one of:

outputting a recommendation for one or more remedial measures;

automatically performing at least one of the remedial measures.

32. The method of claim 31 wherein the recommendation comprises information for a network administrator, and wherein the information enables the network administrator to further diagnose problems in the wireless network.

33. The method of claim 32 wherein the remedial measures comprise increasing the minimum contention window size setting (CWmin) or the arbitration interframe space (AIFS) for the best-effort and background data queues at the wireless access point.

34. The method of claim 31, wherein the remedial measures comprise reducing the CCA and SOP sensitivity of both the wireless access point and wireless clients wireless PHYs.

35. A wireless network management server operative to communicate with a wireless access point in a wireless network, the wireless network management server comprising:

means for receiving a report message comprising an uplink latency histogram or a downlink histogram and at least one of uplink and downlink metric data generated by one or more nodes of a wireless network;

means for analyzing the report messages to determine at least one metric or fault, comprising means for computing jitter using the uplink latency histogram or the downlink histogram; and

means for construct a fault flowchart for the wireless network based on the analysis, wherein for each of the at least one fault determined during the analysis to be associated with the wireless network, the fault flowchart indicates a type and a cause of the fault.