1 Vertical Handover for PMIPv6 KANG Joon-Suk 姜 俊錫

2 Contents Why Vertical Handover Wireless technologies Handover between and Procedure => => Remaining Problems Comments

3 Agenda Why Vertical Handover Wireless technologies Handover between and Procedure => => Remaining Problems Comments

4 Why Vertical Handover Cost/Capacity/Coverage….. If a laptop might be able to use both a high speed wireless LAN and a cellular technology for Internet access. Wireless LAN connections generally provide higher speeds benefit of utilizing the higher bandwidth and lower cost Cellular technologies generally provide more ubiquitous coverage. better mobility support and larger coverage The laptop user might want to use a wireless LAN connection whenever one is available, and to 'fail over' to a cellular connection when the wireless LAN is unavailable.

5 Cases of Vertical HO Switching network to select the best network Handover MN

6 Cases of Vertical HO For just seamless connection Handover MN

7 Agenda Why Vertical Handover Wireless technologies Handover between and Procedure => => Remaining Problems Comments

8 Wireless technologies Wireless LAN IEEE Hot Spot  50~200m 4~11Mbps  Average 2Mbps Low cost IEEE (e) Based on wireless data communication 60km/s(max 100km/s) More than 1Mbps(60km/s) MAX 70~100Mbps Hot Zone or Global coverage Cell coverage : 20km

9 Wireless technologies 3G 3GPP UMTS 3GPP2 CDMA 3.5G HSDPA(High Speed Downlink Packet Access) 3GPP release5 Based on mobile telecommunication Voice/Data Global coverage Average 2~3Mbps MAX 14.4Mbps 4G??? 100Mbps(moving)/1Gbps(standstill)

10 Wireless technologies COST Cellular > IEEE > IEEE Coverage Cellular > IEEE > IEEE IEEE HSDPA + WLAN ??

11 Wireless Data Communication in Japan 2 nd market in the world 2G NTT Docomo PDC KDDI CDMA One 3G NTT Docomo W-CDMA KDDI CDMA 2000

12 Wireless Data Communication in Japan Wireless Internet NTT Docomo Super 3G  Download speed 100Mbps/Upload speed 50Mbps  Based on HSDPA/HSUPA KDDI Ultra 3G  Similar speed to Super 3G  Base on Mobile WiMAX(IEEE e)  Serving with WiFi, ADSL, FTTH SoftBank Based on HSDPA WilCom PHS Emobile HSDPA

13 Wireless Data Communication in Korea Netspot WiFi KT Wibro Based on IEEE e KT HSDPA SKT, KTF Wibro + HSDPA KTF + KT

14 Target L2 IEEE IEEE e HSDPA

15 Agenda Why Vertical Handover Wireless technologies Handover between and Procedure => => Remaining Problems Comments

16 Handover between and BS (RAS) AP MN Router (MAG) LMA: Local Mobility Anchor MAG: Mobile Access Gateway RAS: Radio Access System ACR: Access Control Router LMA ACR (MAG)

17 Handover between and A MN that is connected to enters a hotspot. For cost and bandwidth performance, the MN executes a vertical handover to the network. When leaving the cell, the MN reconnects to the network.

18 Handover between and entering WLAN BS AP MN interface interface Normal operation Beacon Link Detected Normal operation Association Response Link UP Association Request CompletingLayer 3 handover Keep interface on or shutdown interface ??? Selecting by user or Automatically Switching Preparing Layer 3 handover Authentication Response Authentication Request

19 Process To Detect and To Register new BS MNBS Channel Scanning Establish uplink and downlink data connections DL_MAP (Downlink map) Link Detected DCD (Downlink Channel Descriptor) Ranging request Link UP UCD (Uplink Channel Descriptor) UL_MAP (Uplink map) Downlink synchronization Uplink synchronization Ranging response Initial ranging Registration request Registration response Registration Normal operations (data Tx/Rx and maintain synchronization) s s s

20 Handover between and leaving WLAN AP BS MN interface interface Normal operation Link Detected Normal operation Link UP Layer 3 handover Keep interface on or shutdown interface ??? Performed if interface was turned off Link Going Down Preparing Layer 3 handover Link synchronization and registration

21 Agenda Why Vertical Handover Wireless technologies Handover between and Procedure => => Remaining Problems Comments

22 Procedure - Scenario BS (RAS) AP MN Router (MAG) LMA ACR (MAG)

23 Procedure - Scenario Handover based on Network priority Just for seamless Handover Based on the current link status Does It become weaker?

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25 Procedure – contd. 1. Link_Detect event occurs(WLAN) 1. MIH’s Link_Detect event 2. Beacon message 2. MN is attached to the AP nMAG can acquire policy profile. 1. Perform L2 authentication & association process 3. nMAG sends PBU to LMA (to perform BU with LMA) BS (RAS) AP MN Router (nMAG) LMA ACR (pMAG) 1 2 3

26 Procedure – contd. 4. LMA checks BCE list to find out if this MN is already attaching. 5. Register nMAG into the BCE list as a candidate MAG 6. LMA sends VPBA to nMAG 1. Set up virtual tunnel between LMA and nMAG 2. VPBA contains the information of pMAG BS (RAS) AP MN Router (nMAG) LMA ACR (pMAG) 4 MN’s IDMAG’s IDProxy CoAOnHNPLifetime…. apMAGpMAG’s AY anMAGnMAG’s AN… BCE list 5 6

27 Procedure – contd. 7. LMA sends New_Network_Detected message to MN(User) 1. To ask if user want to change network. 2. This massage contains information about nMAG 8. User selects network BS (RAS) AP MN Router (nMAG) LMA ACR (pMAG) 8 MN’s IDMAG’s IDProxy CoAOnL2 typePriority…. apMAGpMAG’s AY anMAGnMAG’s AN … BCE list 7 7

28 Procedure - If User Wants to Keep Current Network 9. User sends boycott message to LMA 10. LMA deletes the entry from BCE list 11. LMA sends boycott message to nMAG 12. L2 connection is canceled between nMAG and MN BS (RAS) AP MN Router (nMAG) LMA ACR (pMAG) MN’s IDMAG’s IDProxy CoAOnL2 typePriority…. apMAGpMAG’s AY anMAGnMAG’s AN … BCE list

29 Procedure - If User Wants to Change Network 9. User sends Change_Network message to LMA via pMAG 10. At pMAG 1. pMAG forward it to LMA 2. pMAG sends ACK to MN 3. pMAG starts fording packets destined for MN to nMAG BS (RAS) AP MN Router (nMAG) LMA ACR (pMAG) MN’s IDMAG’s IDProxy CoAOnL2 typePriority…. apMAGpMAG’s AY anMAGnMAG’s AN … BCE list 10 9

30 Procedure - If User Wants to Change Network As soon as MN receives Ack. from pMAG, MN changes layer2 interface. MN sends Router_Solicitation via interface nMAG acknowledges it by Router_Advertisement MN performs IP address configuration BS (RAS) AP MN Router (nMAG) LMA ACR (pMAG)

31 IP Address Configuration Transport IPv6 MAC1 MAC2 MN Transport IPv6 MAC1 MAC2 MN If. Is Changing but IP is not Changing IP = Net Prefix + IF ID from MAC1 IP = Net Prefix + IF ID from MAC2 IP = Net Prefix + IF ID from MAC1 Simple Modification of Auto-configuration process

32 Procedure - If User Wants to Change Network 15. As soon as LMA receives Network_Change from pMAG, LMA updates BCE list. 16. LMA sends Confirm_BU to nMAG 17. LMA changes forwarding path BS (RAS) AP MN Router (nMAG) LMA ACR (pMAG) MN’s IDMAG’s IDProxy CoAOnL2 typePriority…. apMAGpMAG’s AY anMAGnMAG’s AN … BCE list MN’s IDMAG’s IDProxy CoAOnL2 typePriority…. apMAGpMAG’s AN anMAGnMAG’s AY …

33 Procedure - If User Wants to Change Network 18. After finishing IP configuration of MN, nMAG sends Handover_Complete message to pMAG and LMA 19. Previous connection is closed 1. pMAG & LMA clears binding information of MN BS (RAS) AP MN Router (nMAG) LMA ACR (pMAG) 18 19

34 Automatic Changing - Without User’s opinion According to the network priority ex) >> According to the first service contract between SP and user The early steps are same with previous procedure 1 st step ~ 6 th step

35 Automatic Changing - Procedure 7. LMA sends Change_Network message to pMAG 8. At pMAG 1. pMAG starts forwarding packets destined for MN to nMAG 2. pMAG forwards it to MN 3. pMAG sends Ack. To LMA * nMAG caches the packes for MN BS (RAS) AP MN Router (nMAG) LMA ACR (pMAG) 8 MN’s IDMAG’s IDProxy CoAOnL2 typePriority…. apMAGpMAG’s AY anMAGnMAG’s AN … BCE list 7 8 8

36 9. As soon as MN receives Change_Network from pMAG, MN changes layer2 interface. 10. MN sends Router_Solicitation via interface 11. nMAG acknowledges it by Router_Advertisement 12. MN performs IP address configuration BS (RAS) AP MN Router (nMAG) LMA ACR (pMAG) Automatic Changing - Procedure (contd.)

37 IP Address Configuration Transport IPv6 MAC1 MAC2 MN Transport IPv6 MAC1 MAC2 MN If. Is Changing but IP is not Changing IP = Net Prefix + IF ID from MAC1 IP = Net Prefix + IF ID from MAC2 IP = Net Prefix + IF ID from MAC1 Simple Modification of Auto-configuration process

As soon as LMA receives Ack. from pMAG, LMA updates BCE list. 14. LMA sends Confirm_BU to nMAG 15. LMA changes forwarding path BS (RAS) AP MN Router (nMAG) LMA ACR (pMAG) MN’s IDMAG’s IDProxy CoAOnL2 typePriority…. apMAGpMAG’s AY anMAGnMAG’s AN … BCE list MN’s IDMAG’s IDProxy CoAOnL2 typePriority…. apMAGpMAG’s AN anMAGnMAG’s AY … Automatic Changing - Procedure (contd.)

After finishing IP configuration of MN, nMAG sends Handover_Complete message to pMAG and LMA * nMAG releases the packes cached 16. Previous connection is closed 1. pMAG & LMA clears binding information of MN BS (RAS) AP MN Router (nMAG) LMA ACR (pMAG) Automatic Changing - Procedure (contd.)

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=> When the MN detects that the signal from AP becomes weaker Signal strength Link_Going_Down How to decide a valid threshold MN triggers HO BS (RAS) AP MN Router (nMAG) LMA ACR (pMAG)

42 Procedure 1. MN detects that the signal becomes weaker 2. MN starts detecting another network * If MN finds another ’s network? MN tries to establish the L2 connection with BS 4. MN sends Prepare_Handover message to nMAG BS (RAS) AP MN Router (nMAG) LMA ACR (pMAG)

43 Procedure – contd. Next steps are same with the step3~step17 of ‘the automatic changing procedure’ of ‘ to ’ Only one difference In this case, changing policy does not follow network priority At step 8  When nMAG receives Change_Network message, nMAG already knew that HO must be performed.  Because of step 4

44 The Biggest Problem of network It takes very long time to detect and to register BS P19 of this ppt Before completing connection procedure, previous connection with WLAN will be closed. Link Up stepLatency range (s) Downlink and uplink synchronization Initial ranging Registration

45 How to Solve If detecting procedure begins early? In spite of good signal strength Is it efficient? Maintaining L2 connection of previous network continuously, while MN is being attached to network HO is performed very quickly But it causes resource waste

46 Second Solution 1. MN detects that the signal becomes weaker 2. MN sends Prepare_Handover message to nMAG BS (RAS) AP MN Router (nMAG) LMA ACR (pMAG) 1 2 MN’s IDMAG’s IDProxy CoAOnL2 typePriority…. apMAGpMAG’s AN anMAGnMAG’s AY …

47 Second Solution 3. nMAG sends Change_Network message to LMA 4. LMA updates BCE list. 5. LMA changes forwarding path 6. LMA sends Confirm to nMAG BS (RAS) AP MN Router (nMAG) LMA ACR (pMAG) MN’s IDMAG’s IDProxy CoAOnL2 typePriority…. apMAGpMAG’s AY anMAGnMAG’s AN … BCE list MN’s IDMAG’s IDProxy CoAOnL2 typePriority…. apMAGpMAG’s AN anMAGnMAG’s AY … 6 5

48 Second Solution 7. At nMAG 1. nMAG starts forwarding packets destined for MN to pMAG 2. nMAG sends Ack. To LMA 8. nMAG sends Confirm to MN 9. MN changes layer2 interface. 10. Next steps are same with previous case… BS (RAS) AP MN Router (nMAG) LMA ACR (pMAG) 1 8

49 Agenda Why Vertical Handover Wireless technologies Handover between and Procedure => => Remaining Problems Comments

50 Remaining Problems Adjusting the link Going Down threshold to allow enough time to perform full network entry in would require the MN to trigger an event while the connectivity to the AP is still good. Some solutions to optimize the handover between and include: Keep the interface on Use sleep mode Speed up the network entry by providing heterogeneous information through the interface (Information Service) synchronization phase plays a key role in the handover latency: Any prior knowledge for synchronization (channel descriptor messages) is critical in speeding up the handover. Reducing the synchronization time by increasing the frequency of the channel descriptor messages comes generally at the cost of a higher bandwidth overhead (less bandwidth available for user traffic). Keeping the interface turned on is beneficial at the cost of additional power consumption and reduced battery life. The use of e mechanisms including neighbor advertisement, BS synchronization, and sleep mode may prove to be helpful.

51 Remaining Problems To apply IPv6 to Network, additional technique is needed Convergence Sublayer (CS) IP CS/ Ethernet CS Keeping the interface turned on always? To reduce battery consumption, interface is turned on only at the coexistence area of and Using extra information system

52 Agenda Why Vertical Handover Wireless technologies Handover between and Procedure => => Remaining Problems Comments

53 Comments