Method and apparatus for preventing misrouting of data in a radio communication system

• US 6,246,670 B1
• Filed: 10/16/1997
• Issued: 06/12/2001
• Est. Priority Date: 10/16/1997
• Status: Expired due to Term

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Karlsson, Torgny, Andersson, Dick
• Primary Examiner(s): Pham, Chi H.
• Assistant Examiner(s): YAO, KWANG BIN
• Application Number:
  US08/951,966
• Time in Patent Office: 1,335 Days
• Field of Search: 370/216, 370/241, 370/242, 370/244, 370/245, 370/246, 370/248, 370/250, 370/252, 370/312, 370/313, 370/328, 370/338, 370/349, 370/389, 370/392, 370/401, 370/351, 370/352, 370/353, 370/355, 370/356, 455/432, 455/435, 455/445, 709/227, 709/228, 709/245
• US Class Current: 370/244
• CPC Class Codes: H04L 61/5007 Internet protocol [IP] addresses
• CPC Class Codes: H04L 61/5053 Lease time; Renewal aspects
• CPC Class Codes: H04L 61/5076 Update or notification mechanisms, e.g. DynDNS
• CPC Class Codes: H04L 61/5084 Providing for device mobility network addressing or numbering for mobility support in wireless networks H04W8/26; mobile IP H04W80/04
• 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 69/40 for recovering from a failure of a protocol instance or entity, e.g. service redundancy protocols, protocol state redundancy or protocol service redirection management of faults, events, alarms or notifications in data switching networks H04L41/06
• CPC Class Codes: H04W 76/20 Manipulation of established connections
• CPC Class Codes: H04W 76/30 Connection release
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]

Abstract

A method, and associated apparatus, prevents misrouting of packet-data in a radio communication system subsequent to an abnormal communication session termination by a wireless host. When a determination is made that a communication session between a wireless host and another host has terminated abnormally, a temporary address used to identify the wireless host is not permitted to be immediately reassigned to identify another wireless host. Misrouting of data to another wireless host subsequent to the abnormal communication session, termination is thereby avoided.

Claims

1. In a method for communicating packet data during a communication session between a selected communication station and a wireless communication station by way of a communication network, the wireless communication station identified during the communication session by a dynamically-assigned address, the dynamically-assigned address selected from an address list, an improvement of a method for preventing misrouting of the data subsequent to abnormal session end by the wireless communication station and formation of a half-open connection, said method comprising the steps of:

determining whether the communication session has ended abnormally; and

in response to a determination that the communication session has ended abnormally, updating the address list with an indication that the dynamically-assigned address used temporarily to identify the wireless communication station during the communication session is unavailable for reassignation to identify another wireless communication station for a selected address-unavailable time period.

2. The method of claim 1 comprising the further step of discarding packet data communicated by the selected communication station by way of the communication network and intended for the wireless communication station if the communication session is determined during said step of determining to have ended abnormally.

3. The method of claim 1 wherein the communication session is determined during said step of determining to have ended abnormally in the absence of detection at the communication network of data generated by the wireless communication station for at least a selected time-out period.

4. The method of claim 3 wherein the communication network comprises a PMSC (packet-data mobile switching center) and wherein the communication session is determined during said step of determining to have ended abnormally in the absence of detection of the PMSC of the data generated by the wireless communication station for at least the selected time-out period.

5. The method of claim 4 wherein the address list updated during said step of updating is maintained by the PMSC and wherein said step of updating the address list is performed by the PMSC.

6. The method of claim 1 wherein the selected address-unavailable time period during which the dynamically-assigned address used temporarily to identify the wireless communication station is unavailable is of a length at least as great as a maximum time period before which the selected communication station terminates the communication session.

7. The method of claim 1 comprising the further step of releasing the dynamically-assigned address used temporarily to identify the wireless communication station to be available to identify the another wireless communication station subsequent to expiration of the selected address-unavailable time period.

8. The method of claim 7 wherein said step of releasing comprises updating the address list with an indication that the dynamically-assigned address used temporarily to identify the wireless communication station is available for reassignation to identify the another wireless communication station.

9. The method of claim 1 wherein the wireless communication station comprises a mobile host coupled to a mobile terminal, wherein the communication network comprises a PLMN (public land mobile network) coupled to an IP network, wherein the dynamically-assigned address comprises an IP address which uniquely identifies the mobile host, and wherein the address list updated during said step of updating identifies the mobile host by the IP address together with an availability indicator to indicate whether the IP address is available for reassignation.

10. The method of claim 9 wherein the selected communication station comprises an IP host, the IP host having a keepalive timer associated therewith, and wherein the selected address-unavailable time period during which the IP address used temporarily to identify the wireless IP host is unavailable for reassignation is at least as great as a time-out period of the keepalive timer.

11. In a packet data communication system in which packet data is communicated during a communication session between a selected communication station and a wireless communication station by way of a communication network, the wireless communication station identified during the communication session by a dynamically-assigned address selected from an address list, a combination with the communication network of apparatus for preventing misrouting of the data subsequent to an abnormal communication session end by the wireless communication station, said apparatus comprising:

a determiner coupled to receive indications of communications generated by the wireless communication station, said determiner for determining whether the communication session has ended abnormally; and

an address list updater operable responsive to determinations by said determiner of an abnormal communication session end for updating the address list with an indication that the dynamically-assigned address used temporarily to identify the wireless communication station during the communication session is unavailable for reassignation to identify another wireless communication station for a selected address-unavailable time period.

12. The apparatus of claim 11 wherein said determiner is operable to determine the communication session to have ended abnormally in the absence of detection both of a normal communication session end and of communication generated by the wireless communication station for at least a selected time-out period.

13. The apparatus of claim 11 wherein the communication network comprises a PMSC (packet-data mobile switching center) and wherein said determiner forms a portion of the PMSC.

14. The apparatus of claim 13 wherein said address list updater forms a portion of the PMSC.

15. The apparatus of claim 13 wherein said address list updater is further for updating the address list with an indication that the dynamically-assigned address used temporarily to identify the wireless communication station is available for reassignation to identify the another wireless communication station subsequent to the selected address-unavailable time period.

16. A method for communicating packet data during a communication session between a wireless communication station and a selected communication station by way of a communication network, said method comprising the steps of:

assigning the wireless communication station with a temporary address selected from an address list;

during the communication session, addressing packet data to be communicated to the wireless communication station by the selected communication station with the temporary address assigned during said step of assigning;

during the communication session, sending the packet data, once addressed with the temporary address, from the selected communication station to the wireless communication station;

determining whether the communication session has ended abnormally;

in response to a determination that the communication session has ended abnormally, updating the address list with an indication that the temporary address used temporarily to identify the wireless communication station during the communication session is unavailable for reassignation to identify another wireless communication station for a selected time period; and

discarding additional packet data sent by the selected communication station and intended for the wireless communication station if the communication session is determined during said step of determining to have ended abnormally.

17. Apparatus for a packet data communication network which communicates packet data during a communication session between a selected communication station and a wireless communication station, said apparatus comprising:

an address assignor coupled to receive indications of registration of the wireless communication station with the communication network, said address assignor having an address list and for assigning a temporary address, selected from the address list, to the wireless communication station for identifying the wireless communication station during the communication session;

a determiner coupled to receive communications generated by the wireless communication station, said determiner for determining whether the communication session has ended abnormally; and

an address list updater coupled to said address assignor and operable responsive to determinations of said determiner that the communication session has ended abnormally for updating the address list with an indication that the temporary address used temporarily to identify the wireless communication station during the communication session is unavailable for reassignation to identify another wireless communication station.