Method and apparatus for seamless mobility with layer two assistance

• US 7,009,952 B1
• Filed: 05/24/2001
• Issued: 03/07/2006
• Est. Priority Date: 05/24/2001
• Status: Active Grant

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: 3Com Corporation (HP Inc.)
• Inventors: Subbiah, Barani, Razavilar, Javad
• Primary Examiner(s): VINCENT, DAVID ROBERT
• Application Number:
  US09/865,120
• Time in Patent Office: 1,748 Days
• Field of Search: 370/310, 370/252, 370328-347, 370/320, 370351- 3, 370464-467, 370/469, 370/473, 370/479, 370/445, 370/441, 455436-444
• US Class Current: 370/331
• CPC Class Codes: H04L 69/16 Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
• CPC Class Codes: H04L 69/161 Implementation details of TCP/IP or UDP/IP stack architecture; Specification of modified or new header fields
• CPC Class Codes: H04W 36/0011 for data sessions of end-to-end connection
• CPC Class Codes: H04W 36/14 Reselecting a network or an air interface
• CPC Class Codes: H04W 80/06 Transport layer protocols, e.g. TCP [Transport Control Protocol] over wireless transmission control protocol/Internet protocol [TCP/IP] or user datagram protocol [UDP] H04L69/16
• CPC Class Codes: H04W 80/10 adapted for application session management, e.g. SIP [Session Initiation Protocol] connection management H04W76/00; arrangements for session management H04L67/14

Abstract

One aspect of the present invention includes a method of handing off a network session between two different access technologies, in response to a quality of service metric, while maintaining the session. Additional aspects of the present invention are described in the claims, specification and drawings.

Claims

1. A method of handing off a session from a first access technology to a second access technology based on a quality of service metric, including:

monitoring at a mobile terminal, during a session, a quality of service metric describing a connection via a first access technology, the first access technology including a first entity having an IP stack;

initiating a connection via a second access technology upon the monitored quality of service metric crossing a threshold, while continuing the connection via the first access technology, wherein the second access technology utilizes a different physical layer than the first access technology and includes a second entity having an IP stack;

signaling the first entity to conduct a hand off of the session with the second entity; and

modifying routing tables at the mobile terminal to use the connection via the second access technology to continue the session.

2. The method of claim 1, including further monitoring the quality of service metric while initiating the connection via the second access technology and determining based upon the further monitoring whether to proceed with signaling the first entity.

3. The method of claim 1, including further monitoring the quality of service metric after initiating the connection via the second access technology and determining based upon the further monitoring whether to proceed with signaling the first entity.

4. The method of claim 1, wherein the threshold is a connect threshold, based on when it is preferred to connect to the second access technology.

5. The method of claim 1, wherein the threshold is a disconnect threshold, based on when it is preferred to disconnect from the first access technology.

6. The method of claim 1, wherein the quality of service metric includes a signal to noise ratio.

7. The method of claim 1, wherein the quality of service metric includes a bit error rate.

8. The method of claim 1, wherein the quality of service metric includes a packet loss rate.

9. The method of claim 1, wherein the quality of service metric includes a frame loss rate.

10. The method of claim 1, wherein the quality of service metric includes a measure of network congestion.

11. The method of claim 1, wherein the quality of service metric includes a measure of network transmission delay.

12. The method of claim 1, wherein the quality of service metric includes cost of access via the first access technology and the second access technology.

13. The method of claim 1, wherein the quality of service metric includes service available when using the first access technology and the second access technology.

14. The method of claim 1, wherein the quality of service metric includes security available when using the first access technology and the second access technology.

15. The method of claim 1, wherein the first access technology is compliant with a 802.11x standard.

16. The method of claim 1, wherein the first access technology includes using an unlicensed 2.4 GHz network.

17. The method of claim 1, wherein the first access technology is compliant with a Bluetooth standard.

18. The method of claim 1, wherein the first access technology includes using an RF connection compliant with a Bluetooth standard.

19. The method of claim 1, wherein the session is a TCP session.

20. The method of claim 1, wherein the session is a UDP session.

21. The method of claim 1, wherein the session is a WAP session.

22. The method of claim 1, wherein the session includes a Bluetooth standard compliant transport session.

23. The method of claim 1, wherein the connection via the second access technology is a PPP connection.

24. The method of claim 1, wherein the second access technology is compliant with an IS 95b standard.

25. The method of claim 1, wherein the second access technology is compliant with an enhanced GSM standard.

26. The method of claim 1, wherein the second access technology is compliant with a GPRS standard.

27. The method of claim 1, wherein the second access technology is compatible with access via Metricom.

28. The method of claim 1, wherein the second access technology is made using a cellular telephone network.

29. The method of claim 1, wherein the second access technology is made using an unlicensed 2.4 GHz network.

30. The method of claim 1, wherein the second access technology is made using communication between a satellite and the mobile terminal for at least one direction of the second access technology connection.

31. The method of claim 1, wherein the second access technology is compliant with a Bluetooth standard.

32. The method of claim 1, wherein the second access technology includes using an RF connection compliant with a Bluetooth standard.

33. The method of claim 1, wherein crossing the threshold involves the signal quality metric rising above the threshold.

34. The method of claim 1, wherein crossing the threshold involves the signal quality metric dropping below the threshold.

35. The method of claim 1, wherein crossing the threshold involves the signal quality metric reaching the threshold.

36. The method of claim 1, wherein the routing table at the mobile terminal is kept in a system directory file.

37. The method of claim 1, wherein the routing table at the mobile terminal is kept in a memory.

38. The method of claim 1, wherein modifying the routing table at the mobile terminal includes updating the default interface.

39. The method of claim 1, wherein modifying the routing table at the mobile terminal includes updating the default IP address.

40. The method of claim 1, wherein signaling takes place before modifying.

41. The method of claim 1, wherein modifying takes place before signaling.

42. A method of handing off a session from a WLAN connection to a WWAN connection based on a signal quality metric, including:

monitoring at a mobile terminal during a session a signal quality metric describing a connection to a WLAN;

initiating a connection to a WWAN upon the signal quality metric crossing a disconnect threshold, while continuing the connection to the WLAN;

signaling a first access router to conduct a hand off of the session with a second access router; and

modifying routing tables at the mobile terminal to use the WWAN connection to continue the session.

43. The method of claim 42, including further monitoring the signal quality metric while initiating the connection to the WWAN and determining based upon the further monitoring whether to proceed with signaling the first access router.

44. The method of claim 42, including further monitoring the signal quality metric after initiating the connection to the WWAN and determining based upon the further monitoring whether to proceed with signaling the first access router.

45. The method of claim 42, wherein the signal quality metric is a signal to noise ratio.

46. The method of claim 42, wherein the signal quality metric is a bit error rate.

47. The method of claim 42, wherein the signal quality metric is a packet loss rate.

48. The method of claim 42, wherein the signal quality metric is a frame loss rate.

49. The method of claim 42, wherein the signal quality metric is a measure of network congestion.

50. The method of claim 42, wherein the signal quality metric is a measure of network transmission delay.

51. The method of claim 42, wherein the WLAN connection is compliant with a 802.11x standard.

52. The method of claim 42, wherein the WLAN connection is made using an unlicensed 2.4 GHz network.

53. The method of claim 42, wherein the session is a TCP session.

54. The method of claim 42, wherein the session is a UDP session.

55. The method of claim 42, wherein the connection to the WWAN is a PPP connection.

56. The method of claim 42, wherein the WWAN connection is compliant with an IS 95b standard.

57. The method of claim 42, wherein the WWAN connection is compliant with an enhanced GSM standard.

58. The method of claim 42, wherein the WWAN connection is compliant with a GPRS standard.

59. The method of claim 42, wherein the WWAN connection is compatible with access via Metricom.

60. The method of claim 42, wherein the WWAN connection is made using a cellular telephone network.

61. The method of claim 42, wherein the WWAN connection is made using an unlicensed 2.4 GHz network.

62. The method of claim 42, wherein the WWAN connection is made using communication between a satellite and the mobile terminal for at least one direction of the WWAN connection.

63. The method of claim 42, wherein crossing the disconnect threshold involves the signal quality metric rising above the disconnect threshold.

64. The method of claim 42, wherein crossing the disconnect threshold involves the signal quality metric dropping below the disconnect threshold.

65. The method of claim 42, wherein crossing the disconnect threshold involves the signal quality metric reaching the disconnect threshold.

66. The method of claim 42, wherein the first router controls the WWAN connection and the second router controls the WLAN connection.

67. The method of claim 42, wherein the first router controls the WLAN connection and the second router controls the WWAN connection.

68. The method of claim 42, wherein the routing table at the mobile terminal is kept in a system directory file.

69. The method of claim 42, wherein the routing table at the mobile terminal is kept in a memory.

70. The method of claim 42, wherein modifying the routing table at the mobile terminal includes update updating the default interface.

71. The method of claim 42, wherein modifying the routing table at the mobile terminal includes update updating the default IP address.

72. The method of claim 42, wherein signaling takes place before modifying.

73. The method of claim 42, wherein modifying takes place before signaling.

74. A method of handing off a session from a WWAN to a WLAN based on signal quality metric, including:

monitoring at a mobile terminal, during a session connected to a WWAN, a signal quality metric describing availability of a connection to a WLAN;

initiating a connection to a WLAN upon the signal quality metric crossing a connect threshold, while continuing the connection to the WWAN;

signaling a first access router to conduct a hand off of the session with a second access router; and

modifying routing tables at the mobile terminal to use the WLAN connection to continue the session.

75. The method of claim 74, including further monitoring the signal quality metric while initiating the connection to the WLAN and determining based upon the further monitoring whether to proceed with signaling the first access router.

76. The method of claim 74, including further monitoring the signal quality metric after initiating the connection to the WLAN and determining based upon the further monitoring whether to proceed with signaling the first access router.

77. The method of claim 74, wherein the signal quality metric is a signal to noise ratio.

78. The method of claim 74, wherein the signal quality metric is a bit error rate.

79. The method of claim 74, wherein the signal quality metric is a packet loss rate.

80. The method of claim 74, wherein the signal quality metric is a frame loss rate.

81. The method of claim 74, wherein the signal quality metric is a measure of network congestion.

82. The method of claim 74, wherein the signal quality metric is a measure of network transmission delay.

83. The method of claim 74, wherein the WLAN connection is compliant with a 802.11x standard.

84. The method of claim 74, wherein the WLAN connection is made using an unlicensed 2.4 GHz network.

85. The method of claim 74, wherein the session is a TCP session.

86. The method of claim 74, wherein the session is a UDP session.

87. The method of claim 74, wherein the connection to the WWAN is a PPP connection.

88. The method of claim 74, wherein the WWAN connection is compliant with an IS 95b standard.

89. The method of claim 74, wherein the WWAN connection is compliant with an enhanced GSM standard.

90. The method of claim 74, wherein the WWAN connection is compliant with a GPRS standard.

91. The method of claim 74, wherein the WWAN connection is compatible with access via Metricom.

92. The method of claim 74, wherein the WWAN connection is made using a cellular telephone network.

93. The method of claim 74, wherein the WWAN connection is made using an unlicensed 2.4 GHz network.

94. The method of claim 74, wherein the WWAN connection is made using communication between a satellite and the mobile terminal for at least one direction of the WWAN connection.

95. The method of claim 74, wherein crossing the connect threshold involves the signal quality metric rising above the connect threshold.

96. The method of claim 74, wherein crossing the connect threshold involves the signal quality metric dropping below the connect threshold.

97. The method of claim 74, wherein crossing the connect threshold involves the signal quality metric reaching the connect threshold.

98. The method of claim 74, wherein the first router controls the WWAN connection and the second router controls the WLAN connection.

99. The method of claim 74, wherein the first router controls the WLAN connection and the second router controls the WWAN connection.

100. The method of claim 74, wherein the routing table at the mobile terminal is kept in a system directory file.

101. The method of claim 74, wherein the routing table at the mobile terminal is kept in a memory.

102. The method of claim 74, wherein modifying the routing table at the mobile terminal includes update updating the default interface.

103. The method of claim 74, wherein modifying the routing table at the mobile terminal includes update updating the default IP address.

104. The method of claim 74, wherein signaling takes place before modifying.

105. The method of claim 74, wherein modifying takes place before signaling.

106. A method of handing off a wireless session from a relatively high bandwidth wireless connection to a relatively low bandwidth connection based on a signal quality metric, including:

monitoring at a mobile terminal during a wireless session a signal quality metric describing a relatively high bandwidth connection;

initiating a connection to a relatively low bandwidth connection upon the signal quality metric crossing a disconnect threshold, while continuing the relatively high bandwidth connection;

signaling a first access router to conduct a hand off of the session with a second access router; and

modifying routing tables at the mobile terminal to use the relatively low bandwidth connection to continue the session.

107. The method of claim 106, including further monitoring the signal quality metric while initiating the connection to the relatively low bandwidth connection and determining based upon the further monitoring whether to proceed with signaling the first access router.

108. The method of claim 106, including further monitoring the signal quality metric after initiating the connection to the relatively low bandwidth connection and determining based upon the further monitoring whether to proceed with signaling the first access router.

109. The method of claim 106, wherein the signal quality metric is a signal to noise ratio.

110. The method of claim 106, wherein the signal quality metric is a bit error rate.

111. The method of claim 106, wherein the signal quality metric is a packet loss rate.

112. The method of claim 106, wherein the signal quality metric is a frame loss rate.

113. The method of claim 106, wherein the signal quality metric is a measure of network congestion.

114. The method of claim 106, wherein the signal quality metric is a measure of network transmission delay.

115. The method of claim 106, wherein the relatively high bandwidth connection is compliant with a 802.11x standard.

116. The method of claim 106, wherein the relatively high bandwidth connection is made using an unlicensed 2.4 GHz network.

117. The method of claim 106, wherein the relatively high bandwidth connection is a PPP connection.

118. The method of claim 106, wherein the session is a TCP session.

119. The method of claim 106, wherein the session is a UDP session.

120. The method of claim 106, wherein the relatively low bandwidth connection is a PPP connection.

121. The method of claim 106, wherein the relatively low bandwidth connection is compliant with an IS 95b standard.

122. The method of claim 106, wherein the relatively low bandwidth connection is compliant with an enhanced GSM standard.

123. The method of claim 106, wherein the relatively low bandwidth connection is compliant with a GPRS standard.

124. The method of claim 106, wherein the relatively low bandwidth connection is compatible with access via Metricom.

125. The method of claim 106, wherein the relatively low bandwidth connection is made using a cellular telephone network.

126. The method of claim 106, wherein the relatively low bandwidth connection is made using an unlicensed 2.4 GHz network.

127. The method of claim 106, wherein the relatively low bandwidth connection is made using communication between a satellite and the mobile terminal for at least one direction of the relatively low bandwidth connection.

128. The method of claim 106, wherein crossing the disconnect threshold involves the signal quality metric rising above the disconnect threshold.

129. The method of claim 106, wherein crossing the disconnect threshold involves the signal quality metric dropping below the disconnect threshold.

130. The method of claim 106, wherein crossing the disconnect threshold involves the signal quality metric reaching the disconnect threshold.

131. The method of claim 106, wherein the first router controls the relatively low bandwidth connection and the second router controls the relatively high bandwidth connection.

132. The method of claim 106, wherein the first router controls the relatively high bandwidth connection and the second router controls the relatively low bandwidth connection.

133. The method of claim 106, wherein the routing table at the mobile terminal is kept in a system directory file.

134. The method of claim 106, wherein the routing table at the mobile terminal is kept in a memory.

135. The method of claim 106, wherein modifying the routing table at the mobile terminal includes update updating the default interface.

136. The method of claim 106, wherein modifying the routing table at the mobile terminal includes update updating the default IP address.

137. The method of claim 106, wherein signaling takes place before modifying.

138. The method of claim 106, wherein modifying takes place before signaling.

139. A method of handing off a wireless session from a relatively low bandwidth wireless connection to a relatively high bandwidth connection based on a signal quality metric, including:

monitoring at a mobile terminal during a wireless session a signal quality metric describing availability of a relatively high bandwidth connection;

initiating a connection to a relatively high bandwidth connection upon the signal quality metric crossing a connect threshold, while continuing the relatively low bandwidth connection;

signaling a first access router to conduct a hand off of the session with a second access router; and

modifying routing tables at the mobile terminal to use the relatively high bandwidth connection to continue the session.

140. The method of claim 139, including further monitoring the signal quality metric while initiating the connection to the relatively high bandwidth connection and determining based upon the further monitoring whether to proceed with signaling the first access router.

141. The method of claim 139, including further monitoring the signal quality metric after initiating the connection to the relatively high bandwidth connection and determining based upon the further monitoring whether to proceed with signaling the first access router.

142. The method of claim 139, wherein the signal quality metric is a signal to noise ratio.

143. The method of claim 139, wherein the signal quality metric is a bit error rate.

144. The method of claim 139, wherein the signal quality metric is a packet loss rate.

145. The method of claim 139, wherein the signal quality metric is a frame loss rate.

146. The method of claim 139, wherein the signal quality metric is a measure of network congestion.

147. The method of claim 139, wherein the signal quality metric is a measure of network transmission delay.

148. The method of claim 139, wherein the relatively high bandwidth connection is compliant with a 802.11x standard.

149. The method of claim 139, wherein the relatively high bandwidth connection is made using an unlicensed 2.4 GHz network.

150. The method of claim 139, wherein the relatively high bandwidth connection is a PPP connection.

151. The method of claim 139, wherein the session is a TCP session.

152. The method of claim 139, wherein the session is a UDP session.

153. The method of claim 139, wherein the relatively low bandwidth connection is a PPP connection.

154. The method of claim 139, wherein the relatively low bandwidth connection is compliant with an IS 95b standard.

155. The method of claim 139, wherein the relatively low bandwidth connection is compliant with an enhanced GSM standard.

156. The method of claim 139, wherein the relatively low bandwidth connection is compliant with a GPRS standard.

157. The method of claim 139, wherein the relatively low bandwidth connection is compatible with access via Metricom.

158. The method of claim 139, wherein the relatively low bandwidth connection is made using a cellular telephone network.

159. The method of claim 139, wherein the relatively low bandwidth connection is made using an unlicensed 2.4 GHz network.

160. The method of claim 139, wherein the relatively low bandwidth connection is made using communication between a satellite and the mobile terminal for at least one direction of the relatively low bandwidth connection.

161. The method of claim 139, wherein crossing the connect threshold involves the signal quality metric rising above the connect threshold.

162. The method of claim 139, wherein crossing the connect threshold involves the signal quality metric dropping below the connect threshold.

163. The method of claim 139, wherein crossing the connect threshold involves the signal quality metric reaching the connect threshold.

164. The method of claim 139, wherein the first router controls the relatively low bandwidth connection and the second router controls the relatively high bandwidth connection.

165. The method of claim 139, wherein the first router controls the relatively high bandwidth connection and the second router controls the relatively low bandwidth connection.

166. The method of claim 139, wherein the routing table at the mobile terminal is kept in a system directory file.

167. The method of claim 139, wherein the routing table at the mobile terminal is kept in a memory.

168. The method of claim 139, wherein modifying the routing table at the mobile terminal includes update updating the default interface.

169. The method of claim 139, wherein modifying the routing table at the mobile terminal includes update updating the default IP address.

170. The method of claim 139, wherein signaling takes place before modifying.

171. The method of claim 139, wherein modifying takes place before signaling.