1. IEEE 802.21 MEDIA INDEPENDENT HANDOVER
DCN:
Title: Updated Handover Diagrams for Break before Make case (from DCN: )
Date Submitted: June 26, 2008
Authors or Source(s):
Hongseok Jeon, Vivek Gupta, Junghoon Jee, Changmin Park
Abstract:
Clarify description of the messages on link status changes and add additional link down event to address SB recirc4 comment 9 and 10. Text changes are marked, Figure L-6 was changed.

2. IEEE 802.21 presentation release statements:
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3. L.4.3 Mobile-initiated handover for Break before Make case - Description
Figure L-6 and Figure L-6a shows a mobile-initiated handover flow chart for Proxy Mobile IPv6 (PMIPv6). In this case the MN looses its connectivity with the serving PoA before the target PoA can be notified of MN decision to handover. However, the MN discovers the target PoA, establishes connectivity with the target PoA and then the target PoA notifies serving PoA of handover completion. PMIPv6 signaling is then completed and the packets are then forwarded to the MN's new location. The handover flow operates as follows:
MN receives packets through both Mobile Access Gateway (MAG) 1 located in the serving network and Local Mobility Anchor (LMA), which are primary components of the PMIPv6.
The MN queries the Information Server to get information about available neighboring networks. This information query can be attempted as soon as the MN attaches to a new serving network or periodically for refreshing the information.
MN sends the MIH_MN_HO_Candidate_Query Request message to the Serving PoS for triggering a mobile-initiated handover. This message contains requirements for potential candidate networks.
The Serving PoS sends the MIH_N2N_HO_Query_Resource Request messages to the informed Candi-date PoSs (can be more than one) in order to query the availability of the resource at the candidate networks. The Candidate PoS responds by sending the MIH_N2N_HO_Query_Resource Response message to the Serving PoS. The Serving PoS in turn sends MIH_MN_HO_Candidate_Query Response message to the MN. Finally, the MN decides the handover target based on the result of query about resource availability at the candidate networks.

4. L.4.3 Mobile-initiated handover for Break before Make case - Description (cont.)
The MN unexpectedly looses connectivity with the serving PoS. Upon detecting MN's detachment, PMIPv6 client in the Serving PoS terminates a current binding of the MN via sending Proxy Binding Update with Lifetime set to 0 and requests LMA to buffer packets destined for the MN.
The loss of the link connectivity triggers an MIH_Link_Down event on the MN. Later, the MN receives an MIH_Link_Up event when the WLAN L2 connection is established.
Once the MN establishes the layer 2 connection to the Target PoS, the PMIPv6 client as MIH User in the Target PoS registers the current MN's location to LMA by sending Proxy Binding Update message. LMA updates its Binding Cache Entry with the Proxy Binding Update message and then replies with Proxy Bind-ing Acknowledgement message.
After receiving the Proxy Binding Acknowledgement message, PMIPv6 clients sends Router Advertise-ment message to the MN. The Router Advertisement is constructed with the MN's information obtained from the policy server and LMA. It can be solicited by Router Solicitation message from the MN or periodically transmitted. MN configures IP addresses on its interface, which is currently used to connect to the Tar-get PoS, with the received Router Advertisement message. Once the PMIPv6 procedures are completed, MN receives packets through both MAG 2 and LMA.
After the PMIPv6 execution, the Target PoS sends the MIH_N2N_HO_Complete Request message to the previous Serving PoS. The previous Serving PoS responds the message with MIH_N2N_HO_Complete Response.

5. L.4.3 Mobile-initiated handover for Break before Make case Figure L-6
PMIPv6-Domain
Mobile Node
Serving Network
(MAG1, WiMAX)
Other Network
Candidate Network 1
(MAG2, WLAN)
Candidate Network n
(MAGn, WLAN)
Other Network
LMA
/AAA Server UP
Entity
MIH
User
MIHF
MAC-
WiMAX
MAC-
WLAN
PoA-
WiMAX
PoS-
WiMAX
MIH User
(PMIPv6 Client)
MIIS
Server
PoA-
WLAN
PoS-
WLAN
MIH User
(PMIPv6 Client)
PoA-Cn
PoS-Cn
MIH
User UP
Entity
Traffic flow b/w MN and Serving Network
Traffic flow b/w MAG1 and LMA
Information Query
MIH_Get_Information.request
MIH_Get_Information Request
MIH_Get_Information.confirm
MIH_Get_Information Response
MIH_MN_HO_Candidate_Query.request
Resource Availability Check
MIH_MN_HO_Candidate_Query Request
MIH_MN_HO_Candidate_Query.indication
MIH_N2N_HO_Query_Resource.request
MIH_N2N_HO_Query_Resource Request
MIH_N2N_HO_Query_Resource.indication
MIH_N2N_HO_Query_Resource Request
MIH_N2N_HO_Query_Resource Response
MIH_N2N_HO_Query_Resource.response
MIH_N2N_HO_Query_Resource.indication
MIH_N2N_HO_Query_Resource.confirm
MIH_N2N_HO_Query_Resource Response
MIH_N2N_HO_Query_Resource.response
MIH_N2N_HO_Query_Resource.confirm
MIH_MN_HO_Candidate_Query Response
MIH_MN_HO_Candidate_Query.response
Higher Layer (PMIPv6) Handover Execution
Detect MN’s Dettachment
Proxy Binding Update (Lifetime = 0)
Proxy Binding Acknowledgement
Update BCE and
Buffer Packets

6. L.4.3 Mobile-initiated handover for Break before Make case Figure L-6a
PMIPv6-Domain
Mobile Node
Serving Network
(MAG1, WiMAX)
Other Network
Candidate Network 1
(MAG2, WLAN)
Candidate Network n
(MAGn, WLAN)
LMA UP
Entity
MIH
User
MIHF
MAC-
WiMAX
MAC-
WLAN
PoA-
WiMAX
PoS-
WiMAX
MIH User
(PMIPv6 Client)
MIIS
Server
PoA-
WLAN
PoS-
WLAN
MIH User
(PMIPv6 Client)
PoA-Cn
PoS-Cn
MIH
User UP
Entity
Link Status Change Indication
Link_Down.indication
MIH_Link_Down.indication
Link_Up.indication
MIH_Link_Up.indication
MIH_Link_Up.indication
Higher Layer (PMIPv6) Handover Execution
Detect MN’s Attachment
Proxy Binding Update
Proxy Binding Acknowledgement
(Router Solicitation)
Update BCE and
Forward Buffered Packets
Router Advertisement
Configure WLAN Interface
Traffic flow b/w MN and Candidate Network1
Traffic flow b/w MAG2 and LMA
Resource Release
MIH_N2N_HO_Complete Request
MIH_N2N_HO_Complete.request
MIH_N2N_HO_Complete.indication
MIH_N2N_HO_Complete.response
MIH_N2N_HO_Complete Response
MIH_N2N_HO_Complete.confirm