HK1121901B - Method and wireless transmit/receive unit for media independent handover using operation, administration and maintenance protocol - Google Patents

Description

Method and wireless transmit/receive unit for media independent handover with operation, administration and maintenance agreement

Technical Field

The present invention relates to communication systems. More particularly, the present invention relates to a method and system for Media Independent Handover (MIH) using an ethernet operation, administration and maintenance (OAM) protocol.

Background

IEEE 802.21 provides an architecture that enables seamless handover processing based on measurements and triggers provided by the link layer. IEEE 802.21 defines media independent Event Service (ES), Command Service (CS), and Information Service (IS). IEEE 802.21 also defines a Media Access Control (MAC) layer Service Access Point (SAP) and related primitives for each particular access technology.

Event and Information Service (EIS) of IEEE 802.21MIH requires MAC-or physical layer-based event notification for update of link status between a User Equipment (UE) and an MIH point of service (PoS). MIH EIS events include link connection, link disconnection, link parameter change, link being disconnected, Service Data Unit (SDU) transmission status, link event fallback, pre-triggering (L2 handover imminent), and the like. Now, link layer extensions for supporting MIH EIS are considered for diverse technologies.

For ethernet, link monitoring using continuous information becomes necessary in cases where physical layer signaling is insufficient to detect connectivity status between two communicating peers. IEEE802.3ah Ethernet First Mile (EFM) provides an extension to 802.3 physical layer signaling to facilitate connectivity status determination. IEEE802.3ah provides link monitoring, fault signaling, and far-end loopback. Link monitoring is used to detect and indicate link failures under different conditions, so an entity can detect failed and degraded connections. Failure signaling provides a mechanism by which one entity can signal another entity that it has detected an error. Remote loopback is often used for fault diagnosis, which allows one entity to place another entity in a state where all inbound traffic is reflected back onto the link at once.

IEEE802.1ag (also known as Connection Fault Management (CFM)) specifies protocols, procedures and management objects for supporting transport fault management of end-to-end ethernet networks at the customer, operator and service provider levels. These protocols, procedures and management objects allow discovery and verification of paths through bridges and Local Area Networks (LANs), and detection and isolation of connectivity faults for a particular bridge or LAN.

CFM mechanisms for fault detection include connectivity checks, traceroutes, loopback (ping), alarm indications, etc. in different OAM domains, such as operator, provider, and customer domains. Each maintenance domain uses the destination address and EtherType field (EtherType) to convey CFM messages. CFM messages are originated or accepted at Maintenance End Points (MEPs) after traversing zero or more Maintenance Intermediate Points (MIPs). CFM messages pass transparently through 802.1Q or 802.1ad bridges. Multiple CFM instances can operate simultaneously at multiple levels on the same bridge side.

While conventional techniques provide mechanisms for detecting link problems and providing this information to link endpoints, there is currently no means of utilizing this information as a goal of triggering a handoff operation to an alternative link.

Disclosure of Invention

The present invention relates to a method and system for MIH using ethernet OAM protocol. Link connectivity between the UE and the MIH PoS is monitored by employing an OAM protocol. OAM triggers indicating link status are mapped to MIH events and the MIH events are reported for potential handover. The OAM protocol may be IEEE802.3ah or 802.1 ag. The access network may be an 802.1D bridged network or an 802.1Q bridged network.

The invention discloses a method for media independent switching, which comprises the following steps: monitoring, at the wtru, a link status of a link to a media independent handover service point using an operation, administration and maintenance agreement; mapping operational, administrative and maintenance triggers indicative of a link state to a media independent handover event upon detecting a change in said link state; and reporting the media independent switching event to higher layers.

The invention also discloses a wireless transmitting/receiving unit, comprising: a lower layer entity configured to monitor a link state of a link to a media independent handover service point using an operations, administration and maintenance protocol and to send an operations, administration and maintenance trigger indicating detection of a change in the link state; and a media independent switching entity configured to map the operation, management and maintenance triggers to media independent switching events and to report the media independent switching events to higher layers.

Drawings

Fig. 1 shows functional entities of a UE according to the present invention;

figure 2 shows a UE and an MIH PoS monitoring link status using 802.3ah OAM messages according to the present invention;

figure 3 illustrates an example system for supporting MIH using 802.3ah OAM messages in accordance with a first embodiment of the present invention;

figure 4 shows a UE and an MIH PoS connected through an 802.1D bridged network and monitoring link status using 802.1ag OAM messages according to the present invention;

figure 5 shows a UE and an MIH PoS connected through an 802.1Q bridged network and monitoring link status using 802.1ag OAM messages according to the present invention;

figure 6 illustrates an example system for supporting MIH using 802.3ag OAM messages in accordance with a second embodiment of the present invention.

Detailed Description

Hereinafter, the term "UE" includes, but is not limited to, a wireless and/or wireline transmit/receive unit (TRU), a mobile Station (STA), a fixed or mobile subscriber unit, a pager, or any other type of device capable of operating in a wireless and/or wireline environment.

The features of the present invention may be incorporated into an Integrated Circuit (IC) or be configured in a circuit comprising a multitude of interconnecting components.

According to the present invention, MIH endpoints (i.e., UE and MIH PoS) are considered OAM peers, and link status between the UE and MIH PoS is monitored by employing an OAM protocol (e.g., 802.3ag or 802.1 ag). An OAM trigger indicating the detected link status is mapped to an MIH event. The MIH event is reported to higher layers for potential handover. MIH PoS is a network entity that provides MIH services. The MIH PoS may be located anywhere in the network. For example, the MIH PoS may be located at a point of attachment (PoA) or in a core network. According to the present invention, current link state information is available for MIH capable 802.21 PoS and the PoS may use this information to trigger a handover to an alternative link when reporting that there is a problem with the current link. The present invention provides a mechanism for generally employing the 802.1 link detection mechanism as a handover decision on 802.3 and 802.11 networks.

Fig. 1 shows functional entities of a UE 100 according to the present invention. The UE 100 includes an upper layer 110, an MIH entity 120, and a lower layer 130. Higher layers 110 include Session Initiation Protocol (SIP) entity 112, mobile internet protocol version 4(MIP v.4) entity 114, mobile internet protocol version 6(MIP v.6) entity 116, and so on. Lower layers 130 (i.e., layer 2 and layer 1) include an IEEE802.3 entity 132, an IEEE 802.11 entity 134, an IEEE 802.16 entity 136, a third generation partnership project (3GPP) entity 138, a 3GPP2 entity 140, and so on. The MIH entity 120 receives link events and link information from the lower layer 130. Based on the reported link event and information from the lower layer 130, the MIH entity 120 generates MIH event and information and transmits the MIH event and information to the upper layer 110. The MIH entity 120 receives MIH commands and information from the higher layer 110. Based on the MIH command and information received by the higher layer 110, the MIH entity 120 generates a link command and link information and transmits the link command and link information to the lower layer 130.

Figure 2 shows a UE 202 and MIH PoS208 that employ 802.3ah OAM messages to monitor link status in accordance with the present invention. The connection between the UE 202 and the MIH PoS208 is established via a network 210, which network 210 includes one or more hubs (or relays) 204, 206. The first hub (or repeater) 204 is a PoA. When the UE 202 and the MIH PoS208 are connected via the hubs (or relays) 204, 206, 802.3 physical layer signaling at the layer 1 interface of the UE 202 cannot detect a link event change between the hubs (or relays) 204, 206 and the MIH PoS 208. Thus, since the loss of connectivity between the hubs (or relays) 204, 206 is not visible to either the UE 202 or the MIH PoS208, the end-to-end meaning required for handover decisions is lost. It should be noted that the loss of connectivity beyond MIH PoS208 is beyond what IEEE 802.21 can achieve.

According to the first embodiment of the present invention, MIH endpoints (i.e., UE 202 and MIH PoS 208) are treated as OAM peers, and link status between UE 202 and MIH PoS208 is monitored by employing the 802.3ah protocol. Both the UE 202 and the MIH PoS208 include MIH entities. The PoA204 may include an MIH entity. In this case, the PoA204 operates as an MIH capable PoA. The MIH entity of the UE 202 and MIH PoS208 (optionally, the MIH entity of the MIH PoA204) uses the link status information to generate 802.21MIH event notifications regarding link status.

When link status is detected using the 802.3ah protocol, an OAM trigger is forwarded to the MIH entity of the UE 202 (or MIH PoS208 and MIH PoA 204). The OAM trigger is then mapped to an MIH event by the MIH entity of the UE 202 (or MIH PoS208 and MIH PoA204) and reported to higher layers for triggering handover.

Table 1 shows a mapping of 802.3ah triggers to 802.21 events. Some currently defined MIH events may be related to 802.3ah triggers. The 802.3ah framework allows vendors to extend this subset using custom Type Length Value (TLV) specifications. The 802.3ah link up event indicates that the physical layer has determined the link up and the OAM remote entity is connected, which is mapped to the 802.21 link up event. An 802.3ah link failure event indicates that the physical layer has determined that the local Data Terminal Equipment (DTE) receive direction failed, which is mapped to an 802.21 link down event. An 802.3ah dying gasp event indicates the occurrence of an unrecoverable local failure, which is mapped to an 802.21 link down event.

TABLE 1

Figure 3 illustrates an example system 300 for supporting MIH services using 802.3ah OAM in accordance with this invention. The system 300 includes a UE 302, a Wireless Local Area Network (WLAN)310, an 802.3 network 320, and an MIH PoS 330. The 802.3 network 320 includes a plurality of interconnected hubs (or repeaters) 322, 324. The UE 302 has MIH capability and supports WLAN access technology and 802.3 access technology. The UE 302 and MIH PoS 330 are two OAM peer entities, and the link status between the UE 302 and MIH PoS 330 is monitored by employing the IEEE802.3ah protocol. Upon detecting a certain 802.3ah trigger, the MIH entity of the UE 302 (or MIH PoS 330) maps the 802.3ah trigger to an 802.21 event. Thus, as shown in figure 3, MIH communication between the UE 302 and the MIH PoS 308 is established over one of the WLAN310 and the 802.3 network 320. Based on the reported MIH events, a handover between the WLAN310 and the 802.3 network 320 will be triggered.

According to a second embodiment of the present invention, a link state between a UE and an MIH PoS is monitored by employing an IEEE802.1ag protocol. As shown in fig. 4 and 5, if the UE is connected with the MIHPoS through the 802.1D or 802.1Q bridged network, 802.3 layer 1 event notification or 802.3ah OAM message is not sufficient to detect a loss of connectivity between the UE and the MIH PoS.

Figure 4 shows a UE 402 and an MIH PoS 408 connected through an 802.1D bridged network 410 and monitoring link status using 802.1ag OAM messages according to the present invention. The 802.1D bridged network 410 includes a hub 404 and bridges/switches 405, 406. The connection between the UE 402 to the MIH PoS 408 is established via one or more 802.1D bridges or switches. When the UE 402 and MIH PoS 408 are connected over an 802.1 bridged network 410, 802.3 level physical layer link state notification is insufficient to detect link connectivity to MIH PoS 408 and ieee802.3ah OAM messages do not traverse 802.1D bridges/switches 405, 406.

Figure 5 shows a UE 502 and an MIH PoS 508 connected through an 802.1Q bridged network and monitoring link status using 802.1ag OAM messages according to the present invention. The UE 502 connects to a hub (i.e., PoA) 504. The connection between the PoA 504 to the MIH PoS 508 is established via one or more 802.1Q bridges or switches 512, 522. When the bridges or switches 512, 522 are 802.1Q bridges or switches, reachability to the MIH PoS 508 may be with different connections to different Virtual Local Area Networks (VLANs) 510, 520 due to static configuration or configuration through a spanning tree (spanning tree) running on each bridge. In this case, MIH connectivity between the UE 502 and the MIH PoS 508 needs to be established and monitored on a per VLAN Identification (ID) basis.

According to a second embodiment of the present invention, the 802.1ag protocol of user-level OAM is used to detect end-to-end link status by mapping an 802.1ag Management Information Base (MIB) object to 802.21 pieces of events. Table 2 shows a mapping of 802.1ag MIB objects to 802.21 events.

The 802.1ag MIB object indicating that connectivity is detected or restored is mapped to an 802.21 link connection event. An 802.1ag MIB object indicating a Management Endpoint (MEP) losing contact with one or more MEPs is mapped to an 802.21 link down event. A new 802.1ag MIB object is defined to indicate the number of connectivity check frames that can be lost before indicating a failure, thereby mapping an 802.21 link-down event to an 802.1ag gating gap.

A link being down event is used whenever there is a possibility of link failure (e.g., due to poor radio conditions). With the current link supported via 802.3, when it is determined that the connection is likely to be broken within a short period of time after looking at the number of frames that have been lost, then the link-being broken status will be flagged. For example, if the threshold is set such that ten (10) frames are lost before a link failure is identified, then a link-being-down indication will be issued when the 9 th frame check fails.

TABLE 2

Figure 6 is an exemplary system 600 for supporting MIH services using 802.1ag OAM in accordance with a second embodiment of the present invention. The system 600 includes a UE 602, an 802.11 network 604, an 802.16 network (WIMAX)606, an 802.3 network 608, a home network 614, and an MIH PoS 616. 802.11 network 604 and 802.3 network are connected to home network 614 through 802.1Q bridges 610, 612, respectively. The UE 602 has MIH capability and supports 802.11, 802.16, and 802.3 access technologies. The UE 602 and MIH PoS 616 are two OAM peer entities and the link status between the UE 602 and MIHPoS 616 is monitored by employing an IEEE802.1ag protocol as described above. Upon detecting an 802.1ag event, the MIH entity of the UE 602 (or MIH PoS 616 or PoA in 802.11 network 604, 802.16 network 606, and 802.3 network 608) maps the 802.1ag MIB object to the 802.21 event and triggers an inter-technology handover between the 802.11 network 604, 802.16 network 606, 802.3 network 608, or an intra-network triggering technology handover within an existing connection based on the MIH event. IEEE802.1 QVLAN traffic may be carried over 802.3, 802.11, and 802.16 frames through the associated convergence sublayer. Thus, end-to-end 802.1ag based connectivity is valuable for making an inter-or intra-technology handover decision.

Examples

1. A method for MIH using OAM protocols in a communication system including a User Equipment (UE), an MIH PoS, and a plurality of access networks.

2. The method according to embodiment 1, comprising the steps of: link connectivity between the UE and the MIHPoS is monitored by employing OAM conventions.

3. The method according to embodiment 2, comprising the steps of: once the link status is detected, an OAM trigger indicating the link status is mapped to an MIH event.

4. The method according to embodiment 3, comprising the steps of: the MIH event is reported.

5. The method as in any one of embodiments 2-4 wherein the OAM protocol is IEEE802.3 ah.

6. The method of embodiment 5 wherein an 802.3ah link up event is mapped to an 802.21 link up event.

7. The method as in any one of embodiments 5-6 wherein an 802.3ah link failure event is mapped to an 802.21 link down event.

8. A method as in any of embodiments 5-7 wherein an 802.3ah dying gasp event is mapped to an 802.21 link down event.

9. The method as in any one of embodiments 2-4 wherein the OAM protocol is IEEE802.1 ag.

10. The method of embodiment 9 wherein an 802.1ag MIB object indicating detected connectivity is mapped to an 802.21 link connection event.

11. A method as in any of embodiments 9-10 wherein an 802.1ag MIB object indicating that an MEP has lost contact with one or more MEPs is mapped to an 802.21 link down event.

12. The method as in any one of embodiments 9-11 wherein the 802.21 link-down event is generated based on an 802.1ag MIB object indicating a number of connectivity check frames that can be lost before indicating a failure.

13. The method as in any one of embodiments 1-12, wherein the access network is an 802.1D bridged network.

14. The method as in any one of embodiments 1-12, wherein the access network is an 802.1Q bridged network.

15. A system for MIH using OAM protocols.

16. The system of embodiment 15 comprising a UE.

17. A system as in any of embodiments 15-16 comprising an MIH PoS for providing MIH services.

18. A system as in any of embodiments 15-17 comprising a plurality of access networks.

19. The system of embodiment 18 wherein the UE and the MIH PoS are configured to monitor a link status between the UE and the MIH PoS by employing an OAM protocol.

20. According to the system of embodiment 19, the UE and the MIH PoS are configured to map an OAM trigger indicating the detected link status to an MIH event.

21. The system of embodiment 20, the UE and the MIH PoS are configured to trigger a handover between access networks based on MIH events.

22. The system as in any one of embodiments 15-21 wherein the OAM protocol is ieee802.3 ah.

23. The system of embodiment 22 wherein an 802.3ah link up event is mapped to an 802.21 link up event.

24. The system as in any one of embodiments 22-23 wherein an 802.3ah link failure event is mapped to an 802.21 link down event.

25. The system as in any one of embodiments 22-24 wherein an 802.3ah dying gasp event is mapped to an 802.21 link down event.

26. The system as in any one of embodiments 15-21 wherein the OAM protocol is ieee802.1 ag.

27. The system of embodiment 26 wherein an 802.1ag MIB object indicating detected connectivity is mapped to an 802.21 link connection event.

28. A system as in any of embodiments 26-27 wherein an 802.1ag MIB object indicating that an MEP has lost contact with one or more MEPs is mapped to an 802.21 link down event.

29. The system as in any one of embodiments 26-28 wherein an 802.21 link being down event is generated based on an 802.1ag MIB object indicating a number of connectivity check frames that can be lost before indicating a failure.

30. The system as in any one of embodiments 18-29 wherein the access network is an 802.1D bridged network.

31. The system as in any one of embodiments 18-29 wherein the access network is an 802.1Q bridged network.

32. An apparatus for MIH in a communication system including a UE, an MIH PoS, and a plurality of access networks, employs an OAM protocol.

33. The apparatus of embodiment 32, comprising a lower layer entity configured to: link connectivity between the UE and the MIH PoS is monitored by employing an OAM protocol, and an OAM trigger indicating a detected link status is transmitted.

34. The apparatus of embodiment 33 comprising an MIH entity configured to map an OAM trigger to an MIH event and to report the MIH event.

35. The apparatus as in any one of embodiments 32-34, wherein the OAM agreement is ieee802.3 ah.

36. The apparatus as in embodiment 35 wherein an 802.3ah link up event is mapped to an 802.21 link up event.

37. The apparatus as in any one of embodiments 35-36 wherein an 802.3ah link failure event is mapped to an 802.21 link down event.

38. An apparatus as in any one of embodiments 35-37 wherein an 802.3ah dying gasp event is mapped to an 802.21 link down event.

39. The apparatus as in any one of embodiments 32-34, wherein the OAM protocol is ieee802.1 ag.

40. The apparatus of embodiment 39 wherein an 802.1ag MIB object indicating detected connectivity is mapped to an 802.21 link connection event.

41. An apparatus as in any of embodiments 39-40 wherein an 802.1ag MIB object indicating that an MEP has lost contact with one or more MEPs is mapped to an 802.21 link down event.

42. An apparatus as in any of embodiments 39-41 wherein an 802.21 link being down event is generated based on an 802.1ag MIB object indicating a number of connectivity check frames that can be lost before indicating a failure.

43. An apparatus as in any one of embodiments 32-42 where the access network is an 802.1D bridged network.

44. An apparatus as in any one of embodiments 32-42 where the access network is an 802.1Q bridged network.

Although the features and elements of the present invention are described in the preferred embodiments in particular combinations, each feature or element can be used alone without the other features and elements of the preferred embodiments or in various combinations with or without other features and elements of the present invention.

Claims (22)

1. A method for media independent switching, the method comprising:

monitoring, at the wtru, a link status of a link to a media independent handover service point using an operation, administration and maintenance agreement;

mapping operational, administrative and maintenance triggers indicative of a link state to a media independent handover event upon detecting a change in said link state; and

reporting the media independent handover event to a higher layer.

2. The method of claim 1 wherein the operation, administration and maintenance agreement is IEEE802.3 ah.

3. The method of claim 2, wherein the 802.3ah link up event is mapped to an 802.21 link up event.

4. The method of claim 2, wherein the 802.3ah link failure event is mapped to an 802.21 link down event.

5. The method of claim 2 wherein an 802.3ah dying gasp event is mapped to an 802.21 link down event.

6. The method of claim 1, wherein the operation, administration, and maintenance agreement is ieee802.1 ag.

7. The method of claim 6 wherein the 802.1ag repository object indicating detected connectivity is mapped to an 802.21 link connection event.

8. The method of claim 6 wherein an 802.1ag mib object indicating that a management endpoint has lost contact with one or more management endpoints is mapped to an 802.21 link-down event.

9. The method of claim 6 wherein the 802.21 link being down event is generated based on an 802.1ag management information base object indicating a number of connectivity check frames that can be lost before indicating a failure.

10. The method of claim 1, wherein the access network is an 802.1D bridged network.

11. The method of claim 8, wherein the access network is an 802.1Q bridged network.

12. A wireless transmit/receive unit, comprising:

a lower layer entity configured to monitor a link state of a link to a media independent handover service point using an operations, administration and maintenance protocol and to send an operations, administration and maintenance trigger indicating detection of a change in the link state; and

a media independent switching entity configured to map the operation, management and maintenance triggers to media independent switching events and to report the media independent switching events to higher layers.

13. The wtru of claim 12 wherein the operation, administration and maintenance agreement is IEEE802.3 ah.

14. The wtru of claim 13 wherein an 802.3ah link up event is mapped to an 802.21 link up event.

15. The wireless transmit/receive unit of claim 13, wherein an 802.3ah link failure event is mapped to an 802.21 link down event.

16. The wtru of claim 13 wherein an 802.3ah dying gasp event is mapped to an 802.21 link down event.

17. The wireless transmit/receive unit of claim 12, wherein the operation, administration and maintenance protocol is IEEE802.1 ag.

18. The wtru of claim 17 wherein an 802.1ag mib object indicating detected connectivity is mapped to an 802.21 link connection event.

19. The wtru of claim 17 wherein an 802.1ag mib object indicating that a management endpoint has lost contact with one or more management endpoints is mapped to an 802.21 link down event.

20. The wireless transmit/receive unit of claim 17, wherein an 802.21 link being down event is generated based on an 802.1ag management information base object indicating a number of connectivity check frames that can be lost before indicating a failure.

21. The wireless transmit/receive unit of claim 12, wherein the access network is an 802.1D bridged network.

22. The wireless transmit/receive unit of claim 12, wherein the access network is an 802.1Q bridged network.