Method for a wireless station to determine network metrics prior to associating with an access point of a wireless network

• US 20040066759A1
• Filed: 10/21/2002
• Published: 04/08/2004
• Est. Priority Date: 10/03/2002
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Lucchina, Massimo G., Molteni, Marco
• Granted Patent: US 7,613,142 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04L 41/048 mobile agents
• CPC Class Codes: H04L 41/5009 Determining service level performance parameters or violations of service level contracts, e.g. violations of agreed response time or mean time between failures [MTBF]
• CPC Class Codes: H04L 63/029 Firewall traversal, e.g. tunnelling or, creating pinholes
• CPC Class Codes: H04L 63/0428 wherein the data content is protected, e.g. by encrypting or encapsulating the payload
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 8/02 Processing of mobility data, e.g. registration information at HLR [Home Location Register] or VLR [Visitor Location Register]; Transfer of mobility data, e.g. between HLR, VLR or external networks
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

In a wireless station, a method includes, prior to the station being associated with a wireless network, wirelessly receiving L2 frames transmitted from one or more wireless access points (APs) of one or more wireless networks that the station can hear, and gathering information about the received L2 data units, including L2 information and L3 information. The method further includes maintaining the gathered information as a wireless network database that includes for each wireless network, a unique identifier of the wireless network; an indication of the quality of communication between the station and the AP of the wireless network; and one or more L3 advertisements from one or more IP-enabled service providers that the AP of the wireless network transmits. The indication of the quality of communication between the AP of the wireless network includes one or more network performance metrics obtained by temporarily associating with the AP, sending one or more probe packets to the AP, and collecting the one or more network performance metrics.

Claims

1. In a wireless station having a wireless network device, the device capable of providing a link-layer (L2) interface to a wireless network, a method comprising:

prior to the station being associated with a wireless network via the wireless network device, wirelessly receiving link layer (L2) data units transmitted from one or more wireless access points (APs) of one or more wireless networks that the station can hear;

prior to the station being associated with a wireless network via the wireless network device, gathering information about the received L2 data units, including L2 information and network layer (L3) information; and

for one or more access points of interest from which one or more L2 data units are received, sending probe packets from the station via the access point of interest to determine one or more network performance metrics, such that the station may associate with a wireless network according to one or more selection criteria, the selection criteria including the network performance metrics and the L3 information gathered at L2.

2. A method as recited in claim 1,

wherein the L3 information gathered at L2 for an AP includes whether the AP is sending one or more L3 packets from one or more mobility agents,

such that the station may associate with a wireless network that is in communication with a mobility agent.

3. A method as recited in claim 1, further comprising:

storing information in a database about one or more wireless networks that the station can hear, including L2 information, L3 information, and one or more of the network performance metrics.

4. A method as recited in claim 3, wherein the sending of probe packets via the access point of interest includes:

associating with the access point of interest;

sending the probe packets to a target node;

receiving one or more responses from the target node;

determining the one or more one or more network performance metrics; and

unassociating with the access point of interest.

5. A method as recited in claim 3, wherein the L2 data units from the APs of the one or more wireless networks that the station can hear conform to one of the IEEE 802.11 standards.

6. A method as recited in claim 3, wherein the information stored about each wireless network includes:

a unique identifier of the wireless network;

an indication of the quality of communication from the AP of the wireless network, including one or more of the network performance metrics; and

one or more L3 advertisements from one or more IP-enabled service providers that the AP of the WLAN transmits.

7. A method as recited in claim 6, wherein one or more of the IP-enabled service providers are mobility agents, such that an L3 process can select an AP to associate with from the wireless network database based on one or more of whether or not the AP is in communication with a mobility agent and the indication of the quality of communication.

8. A method as recited in claim 7,

wherein the mobility agent is a Mobile IP foreign agent sending IP packets conforming to IPv4 or an access router sending IP packets conforming to IPv6, and

wherein said station is a router that provides Mobile IP services,

such that after association with an AP in communication with the mobility agent, the station is mobile router.

9. A method as recited in claim 6, wherein the information stored about each wireless network further includes a timestamp of when the gathered information was last updated.

10. A method as recited in claim 6, wherein the performance metrics are between the station and a target node and include one or more metrics between the station and a target node of the set consisting of response time, one-way delay, jitter, packet loss statistics, data link switching peer tunnel performance, and one or more Website performance metrics such as DNS lookup, TCP connect and HTTP transaction time.

11. A method as recited in claim 6, wherein the one or more network performance metrics are obtained using Service Assurance Agent (SAA) under IOS.

12. A method as recited in claim 10, wherein the target node is the AP of the wireless network.

13. A method as recited in claim 10, wherein the target node is a mobility agent in communication with the AP of the wireless network.

14. A method as recited in claim 13, wherein the performance metrics include one or more of the number of endpoints registered with the mobility agent and the number of tunnels the mobility agent is supporting.

15. A method as recited in claim 10, wherein the station includes a plurality of wireless network devices each capable of providing an interface to a wireless network, and wherein the information stored about each wireless network further includes an indication of which wireless network device received the L2 data unit.

16. A method as recited in claim 10, wherein the database further stores an indication of which wireless network information is of the most recent association to a wireless network.

17. A method as recited in claim 16, further comprising:

periodically updating the database,

wherein the database includes a record for each wireless network, and wherein the record of the most recently associated wireless network is not evicted from the database.

18. A method as recited in claim 10, further comprising:

periodically updating the database.

19. A method as recited in claim 18, wherein the updating of an entry is attempted only if the entry is stale and not expensive.

20. A method as recited in claim 6, wherein the database entries are in an order according to one or more ordering criteria.

21. A method as recited in claim 20, wherein the ordering criteria are related to the selection criteria.

22. A method as recited in claim 6, further comprising:

prior to the station being associated with a wireless network, L3 accepting one or more L3 packets found in the gathering step.

23. A method as recited in claim 22, wherein the accepting by L3 is in an order according to one or more ordering criteria.

24. A method as recited in claim 22, further comprising:

associating with a particular wireless network from where an L2 data unit was received that contains a particular L3 packet containing a mobility agent advertisement, such that after the associating, the wireless network interface of the station provides an interface to the particular wireless network that is in communication with the mobility agent that sent the particular L3 packet.

25. A method as recited in claim 24, further comprising:

after the associating, determining that a re-association is necessary;

selecting for re-associating a wireless network according to one or more re-association criteria; and

re-associating with the selected wireless network.

26. A method as recited in claim 25, wherein the re-association criteria include that the selected wireless network is in communication with the mobility agent that the station was registered with at the time of the determining that a re-association is necessary.

27. A method as recited in claim 24,

wherein the mobility agent that sent the particular mobility agent advertisement is a Mobile IP foreign agent sending IP packets conforming to IPv4 or an access router sending IP packets conforming to IPv6, and

wherein said station is a router that provides Mobile IP services,

such that after association with an AP in communication with the mobility agent that sent the particular mobility agent advertisement, the station is mobile router.

28. A method as recited in claim 27, further comprising:

after the association with an AP in communication with the mobility agent, locking the association.

29. A method as recited in claim 6, wherein the gathering information prior to associating includes:

emulating one or more interfaces to one or more wireless networks that the station can hear, each said emulated interface thus forming a floating interface that after association can become an actual interface to a wireless network that is in communication with one or the IP-enabled service providers.

30. A method as recited in claim 6, further comprising:

selecting a wireless network for association whose AP the station can hear, the selecting according to the one or more selection criteria,

wherein at least one of the selection criteria uses at least some of the gathered information.

31. A method as recited in claim 30, wherein the selection criteria include that the L2 data unit received from the AP of the selected wireless network includes a mobility agent advertisement, such that after association, the station is in communication with a mobility agent.

associating with a particular wireless network from where an L2 data unit containing a particular L3 mobility agent advertisement was received,

such that after the associating, the wireless network interface of the station provides an interface to the particular wireless network that is in communication with the mobility agent that sent the particular L3 mobility agent advertisement.

32. A method as recited in claim 31, further comprising:

associating with a particular selected wireless network from where an L2 data unit containing a particular mobility agent advertisement was received,

such that after the associating, the wireless network interface of the station provides an interface to the particular wireless network that is in communication with the mobility agent that sent the particular mobility agent advertisement.

33. A method as recited in claim 32, further comprising:

at L3 of the station, registering with the mobility agent by exchanging L3 packets with the mobility agent.

34. A method as recited in claim 33, further comprising:

after the associating, determining that a re-association is necessary;

selecting for re-associating a wireless network according to one or more re-association criteria; and

re-associating with the selected wireless network.

35. A method as recited in claim 32,

wherein the mobility agent that sent the particular mobility agent advertisement is a Mobile IP foreign agent sending IP packets conforming to IPv4 or an access router sending IP packets conforming to IPv6, and

wherein said station is a router that provides Mobile IP services,

such that after association with an AP in communication with the mobility agent that sent the particular mobility agent advertisement, the station is mobile router.

36. A method as recited in claim 6,

wherein the station includes one or more wireless network devices each capable of providing a link-layer interface to a wireless network, and

wherein the receiving is of L2 data units from APs that each of the wireless network devices can hear,

the method further comprising:

based on the gathered information, emulating at L2 one or more interfaces to one or more wireless networks whose APs the one or more wireless network devices can hear as if the station was associated to the wireless network via the device, without there necessarily being any association with any wireless network, each emulated interface thus forming a floating interface to a wireless network via a wireless network device that after association can become an actual interface to the wireless network via the wireless network device,

L3 accepting one or more L3 packets that were in L2 data units from one or more APs via one or more of the floating interfaces as if the station was associated with the one or more APs whose L2 data units included the L3 packets.

37. A method as recited in claim 36, wherein the accepting by L3 is in an order according to one or more ordering criteria.

38. A method as recited in claim 1,

wherein the station includes one or more wireless network devices each capable of providing a link-layer interface to a wireless network, and

wherein the receiving is of L2 data units from APs that each of the wireless network devices can hear,

the method further comprising:

based on the gathered information, emulating at L2 one or more interfaces to one or more wireless networks whose APs the one or more wireless network devices can hear as if the station was associated to the wireless network via the device without there necessarily being any association with the wireless network, each emulated interface thus forming a floating interface to a wireless network via a wireless network device that after association can become an actual interface to the wireless network via the wireless network device; and

storing information about the floating interfaces in a database.

39. A method as recited in claim 38, wherein the information stored about each floating interface includes:

a unique identifier of the wireless network of the floating interface;

and the state of the floating interface to the wireless network;

an indication of the quality of communication via the floating interface, including one or more of the network performance metrics; and

one or more L3 advertisements from one or more IP-enabled service providers that the AP of the WLAN transmits.

40. A method as recited in claim 39,

wherein the station includes a plurality of wireless network devices each capable of providing an interface to a wireless network, and

wherein the database further includes an indication of which wireless network device the floating interface is for.

41. A method as recited in claim 39, wherein the information stored about each floating interface includes an indication of any mobility information contained in any L3 information in the received L2 information.

42. A method as recited in claim 39, wherein the database further stores an indication of which floating interface was the most recently used association to a wireless network.

43. A method as recited in claim 42, further comprising:

periodically updating the database of floating interfaces,

wherein the database includes a record for each floating interface, and wherein the record of the floating interface most recently used in an association is not evicted from the wireless network database.

44. A method as recited in claim 42, further comprising:

periodically updating the database of floating interfaces.

45. A method as recited in claim 7, wherein the mobility agent is a Mobile IP foreign agent sending IP packets conforming to IPv4 or an access router sending IP packets conforming to IPv6.

46. In a wireless station that includes a processor, a memory, and a wireless network device, a method comprising:

prior to the station being associated with a wireless network via the wireless network device, wirelessly receiving link layer (L2) data units transmitted from one or more wireless access points (APs) of one or more wireless networks that the station can hear;

prior to the station being associated with a wireless network via the wireless network device, gathering information about the received L2 data units, including L2 information and network layer (L3) information; and

maintaining the information in the memory in the form of a wireless network database, the wireless network database including for each wireless network whose access point the station can hear, the gathered L2 information and the gathered L3 information.

47. A method as recited in claim 46, wherein, for each wireless network whose access point the station can hear, the wireless network database includes:

a unique identifier of the wireless network;

an indication of the quality of communication between the station and the AP of the wireless network; and

one or more L3 advertisements from one or more IP-enabled service providers that the AP of the wireless network transmits.

48. A method as recited in claim 47, wherein the indication of the quality of communication between the AP of the wireless network includes one or more network performance metrics obtained by temporarily associating with the AP, sending one or more probe packets to the AP, and collecting the one or more network performance metrics.

49. A method as recited in claim 48, wherein one or more network performance metrics between the station and a particular AP is further stored at the particular AP.

50. A method as recited in claim 48, wherein the wireless network operates under one of the IEEE 802.11 standards.

51. A method as recited in claim 48, wherein the one or more network performance metrics include one or more of the set of metrics consisting of response time, one-way delay, jitter, packet loss statistics, data link switching peer tunnel performance, and one or more Website performance metrics such as DNS lookup, TCP connect and HTTP transaction time.

52. A method as recited in claim 48, wherein the one or more network performance metrics are obtained using Service Assurance Agent (SAA) under IOS.

53. A method as recited in claim 48, wherein one or more of the IP-enabled service providers are mobility agents, such that an L3 process can select an AP to associate with from the wireless network database based on one or more of whether or not the AP is in communication with a mobility agent and the indication of the quality of communication.

54. A wireless station comprising:

a processor;

a memory coupled to the processor; and

a wireless network device coupled to the processor and capable of providing a link-layer (L2) interface to a wireless network;

the memory loadable with a protocol stack and instructions for the processor to carry out a method including;

prior to the station being associated with a wireless network via the wireless network device, wirelessly receiving link layer (L2) data units transmitted from one or more wireless access points (APs) of one or more wireless networks that the station can hear;

prior to the station being associated with a wireless network via the wireless network device, gathering information about the received L2 data units, including L2 information and network layer (L3) information; and

maintaining the information in the memory in the form of a wireless network database, the wireless network database including for each wireless network whose access point the station can hear, the gathered L2 information and the gathered L3 information.

55. A wireless station as recited in claim 54, wherein, for each wireless network whose access point the station can hear, the wireless network database includes:

a unique identifier of the wireless network;

an indication of the quality of communication between the AP of the wireless network; and

one or more advertisements from one or more IP-enabled service providers that the AP of the wireless network transmits.

56. A wireless station as recited in claim 55, wherein the indication of the quality of communication between the AP of the wireless network includes one or more network performance metrics obtained by the station temporarily associating with the AP, sending one or more probe packets to the AP, and collecting the one or more network performance metrics.

57. A wireless station as recited in claim 56, wherein one or more network performance metrics between the station and a particular AP is further stored at the particular AP.

58. A wireless station as recited in claim 56, wherein the wireless network operates under one of the IEEE 802.11 standards.

59. A wireless station as recited in claim 56, wherein the one or more network performance metrics include one or more of the set of metrics consisting of response time, one-way delay, jitter, packet loss statistics, data link switching peer tunnel performance, and one or more Website performance metrics such as DNS lookup, TCP connect and HTTP transaction time.

60. A wireless station as recited in claim 56, wherein the one or more network performance metrics are obtained using Service Assurance Agent (SAA) under IOS.

61. A wireless station as recited in claim 56, wherein one or more of the IP-enabled service providers are mobility agents, such that an L3 process can select an AP to associate with from the wireless network database based on one or more of whether or not the AP is in communication with a mobility agent and the indication of the quality of communication.

62. A carrier medium carrying computer readable code segments to instruct one or more processors to implement a method, the one or more processors in a wireless station, the station having a memory coupled to the processors and a wireless network device, the device capable of providing a link-layer (L2) interface to a wireless network, the method comprising:

prior to the station being associated with a wireless network via the wireless network device, wirelessly receiving link layer (L2) data units transmitted from one or more wireless access points (APs) of one or more wireless networks that the station can hear;

prior to the station being associated with a wireless network via the wireless network device, gathering information about the received L2 data units, including L2 information and network layer (L3) information; and

maintaining the information in the memory in the form of a wireless network database, the wireless network database including for each wireless network whose access point the station can hear, the gathered L2 information and the gathered L3 information.

63. A carrier medium as recited in claim 62, wherein, for each wireless network whose access point the station can hear, the wireless network database includes:

a unique identifier of the wireless network;

an indication of the quality of communication between the station and the AP of the wireless network; and

one or more L3 advertisements from one or more IP-enabled service providers that the AP of the wireless network transmits.

64. A carrier medium as recited in claim 63, wherein the indication of the quality of communication between the AP of the wireless network includes one or more network performance metrics obtained by temporarily associating with the AP, sending one or more probe packets to the AP, and collecting the one or more network performance metrics.

65. A carrier medium as recited in claim 64, wherein one or more of the IP-enabled service providers are mobility agents, such that an L3 process can select an AP to associate with from the wireless network database based on one or more of whether or not the AP is in communication with a mobility agent and the indication of the quality of communication.

66. A wireless station comprising:

a wireless network device;

means for wirelessly receiving link layer (L2) data units transmitted from one or more wireless access points (APs) of one or more wireless networks that the station can hear, the wirelessly receiving prior to the station being associated with a wireless network via the wireless network device;

means for gathering information about the received L2 data units, including L2 information and network layer (L3) information, the gathering prior to the station being associated with a wireless network; and

memory means for maintaining the gathered information in the form of a wireless network database, the wireless network database including for each wireless network whose access point the station can hear, the gathered L2 information and the gathered L3 information.

67. A wireless station as recited in claim 66, wherein, for each wireless network whose access point the station can hear, the wireless network database includes:

a unique identifier of the wireless network;

an indication of the quality of communication between the station and the AP of the wireless network; and

one or more L3 advertisements from one or more IP-enabled service providers that the AP of the wireless network transmits.

68. A wireless station as recited in claim 67, wherein the station includes means for collecting the one or more network performance metrics between the station and a target node via the AP, and wherein the indication of the quality of communication between the AP of the wireless network includes one or more network performance metrics obtained using the means for collecting.

69. A wireless station as recited in claim 67, wherein a particular AP includes means for storing one or more one or more network performance metrics, and wherein the one or more network performance metrics between the station and the particular AP is further stored by the means for storing.

70. A wireless station as recited in claim 68, wherein the wireless network operates under one of the IEEE 802.11 standards.

71. A wireless station as recited in claim 68, wherein the one or more network performance metrics include one or more of the set of metrics consisting of response time, one-way delay, jitter, packet loss statistics, data link switching peer tunnel performance, and one or more Website performance metrics such as DNS lookup, TCP connect and HTTP transaction time.

72. A wireless station as recited in claim 68, wherein the means for collecting the one or more network performance metrics includes Service Assurance Agent (SAA) operating under IOS.

73. A wireless station as recited in claim 68, wherein one or more of the IP-enabled service providers are mobility agents, such that an L3 process can select an AP to associate with from the wireless network database based on one or more of whether or not the AP is in communication with a mobility agent and the indication of the quality of communication.