1. IEEE 802.21 MEDIA INDEPENDENT HANDOVER DCN: 21-07-0205-01-0000
Title: Handover Flow Diagrams Update
Date Submitted: May 14, 2007
Presented at IEEE session in Montreal, QC, Canada
Authors or Source(s): Junghoon Jee

2. IEEE 802.21 presentation release statements
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3. Overview
IEEE P802.21/D05.00 specifies handover procedures in the Annex A.
A.1 Mobile-initiated handover procedure
A.2 Network-initiated handover procedure
A.3 Network-initiated handover from to 3G (Single PoS)
A.4 Handover from 3G to WLAN
A.5 Example handover flow chart between and
A.6 Example handover flow charts for Mobile IP
A.7 Handover flow diagram for abnormal cases

4. Problems from Annex A
Protocol message naming inconsistency with the normative part.
Use of previous MIH_Switch.
Different assumption about the relationship MIH primitive and lower layer connection setup or higher layer execution.
Relationship between MIH_Net(MN)_HO_Commit and L2 connection setup.
Relationship between MIH_MIH_MN_HO_Complete and MIP registration.
Related contributions
HO_SignallingDiagrams (A2, A3, A4.1, A4.2)
Optimization about A.4.1 and A.4.2 (A4.1, A4.2)

5. Resolution Guideline
Follow the protocol name as defined from the normative part
For example, MIH_Net_HO_Candidate_Query Request
Four Steps
Step 1. Resource Query
MIH_(MN)Net_HO_Candiate_Query
MIH_N2N_HO_Candidate_Query
Step 2. Resource Preparation
MIH_N2N_HO_Commit
Step 3. Handover Commitment
MIH_(MN)Net_HO_Commit
MIH_Configure_Link
Step 4. Handover Complete
MIH_MN_HO_Complete
MIH_N2N_HO_Complete

6. Mobile-initiated case

7. Network-initiated case

8. Working Status Contributors Juan-Carlos Zuniga Yoshihiro Ohba
Junxiang Guo
Junghoon Jee
Amendment role
A.1 and A.2 : Junghoon Jee
A.3 and A.4 : Juan-Carlos
A.4 – A.7 : Junxiang Guo

9. Issue Lists
Who is in charge of deciding the establishment of new layer 2 connection?
MIH User or MIHF itself?
Currently there exists inconsistency between mobile-initiated and network-initiated case
Mobile-initiate case
MIH User commands MIH_Configure_Link.request after the step of receiving the MIH_MN_HO_Commit.confirm from MIHF.
Network-initiated case
MIHF commands Link_Action.request when receiving MIH_Net_HO_Commit Request from Serving PoS.
layer 2 connection and performs higher layer handover procedure.
Should we allow for MIH User on Mobile Node to reject the handover commitment request from Serving PoS in case of network-initiated?

10. Issue Lists (2)
When should MN send MIH_Net_HO_Commit Response to Serving PoS?
After the layer 2 connection establishment or higher layer handover execution?
Primitive and Message Naming
Mobile-initiated case
MIH_MN_HO_Commit and MIH_N2N_HO_Commit are used for requesting resource preparation at the target network not for actual handover execution.
Previous MIH_Handover_Prepare is more right term in this case.
Network-initiated case
MIH_N2N_HO_Commit is used to request resource preparation at the target network as well.
Previous MIH_Handover_Prepare is more right term in this case
MIH_HO_Complete Request
What’s the exact context? Handover is already completed when receiving this request.
Main role is to release resource at the serving network.

11. Issue Lists (3) MIH_HO_Complete
The sender of MIH_HO_Complete Request needs to identify that higher layer handover execution is completed.
Mobile Node is the right entity to initiate sending the request in case of Mobile IP.
Target PoS is the right entity to initiate sending this request in case of Proxy Mobile IP. However, here we are assuming that PoS is on the AR/MAG.
Therefore, MIH_MN_Complete Request can be optional depending on which MM is utilized.