Mobility Management in Wireless Environments

1
Mobility Management in Wireless Environments

• Wei Kuang Lai (???)
• Department of Computer Science and Engineering
• National Sun Yat-sen University, Kaohsiung, Taiwan

2
Outline

• Mobile Networking
• Mobile IPv4, Mobile IPv6
• Established Techniques
• Innovative Approaches
• Q A

3
Mobile Networking

• Why Mobility?
• Seamless Handover and Challenges
• Handover Latency
• Mobile IPv4
• Mobile IPv6

4
Establish Techniques

• Layer 2 Triggering
• Optimistic DAD
• Hierarchical Mobile IPv6
• Fast Handover

5
Innovative Approaches

• Stealth-time HMIP
• Multicast-supported FMIPv6
• Anycast-supported FMIPv6
• Service Migration

6

• Thank you for your attention!
• Q A
• This slide can be downloaded from
  http//bit.kuas.edu.tw/csshieh/misc/nuk-2008.zip

7
Mobile Networking

• Why mobility?
• Pervasion of wireless networks
• Ubiquitous computing
• Heterogeneous networks, overlay networks,
• Notebook computer, PDA, cell phone,
• Desire for freedom
• Keeping connected anywhere, anytime, and in any
  ways

8
Mobile Networking (cont)

• Handover
• The procedure that needs to be taken as a mobile
  node moving across different network domains to
  retain the continuation of ongoing services
• Challenges to seamless handover
• Transparent to applications
• Minimal delay
• Minimal packet loss

9
Mobile Networking (cont)

• Handover at different layers
• Application-layer
• VoIP (Voice over IP) using SIP (Session
  Initiation Protocol)
• Transport-layer
• Dual-homing in SCTP (Stream Control Transmission
  Protocol)
• Network-layer
• MIPv4, MIPv6,

10
Mobile Networking (cont)

• Handover latency

• Duplicate Address Detection (DAD) dominates

11
Mobile IPv4

• Seamless mobility
• Home Address for identification and Care-of
  Address (CoA) for routing
• Binding update
• Tunneling of packets by Home Agent and Foreign
  Agent

12
Mobile IPv4 (cont)
Obtaining CoA
MN Mobile Node CN Correspondent Node HA Home
Agent FA Foreign Agent CoA Care-of Address
Obtain CoA
13
Mobile IPv4 (cont)
Registering CoA
MN Mobile Node CN Correspondent Node HA Home
Agent FA Foreign Agent CoA Care-of Address
14
Mobile IPv4 (cont)
Tunneling Triangular Routing
MN Mobile Node CN Correspondent Node HA Home
Agent FA Foreign Agent CoA Care-of Address
15
Mobile IPv6

• Built-in mobility supports in IPv6
• Address auto-configuration
• Route optimization
• No need for Foreign Agent

16
Mobile IPv6 (cont)
Obtaining CoA
MN Mobile Node CN Correspondent Node HA Home
Agent AR Access Router DAD Duplicate Address
Detection CoA Care-of Address
3. DAD form CoA
17
Mobile IPv6 (cont)
Registering CoA
5. DAD for Home Address
MN Mobile Node CN Correspondent Node HA Home
Agent AR Access Router DAD Duplicate Address
Detection CoA Care-of Address
18
Mobile IPv6 (cont)
Triangular Routing
MN Mobile Node CN Correspondent Node HA Home
Agent AR Access Router CoA Care-of Address
19
Mobile IPv6 (cont)
Bi-directional Tunneling
MN Mobile Node CN Correspondent Node HA Home
Agent AR Access Router CoA Care-of Address
Tunneling
20
Mobile IPv6 (cont)
Direct Routing (Route Optimization)
MN Mobile Node CN Correspondent Node HA Home
Agent AR Access Router CoA Care-of Address
21
Layer 2 Triggering (cont)
MN Mobile Node CN Correspondent Node AP Access
Point
Signal Strength
22
Optimistic DAD
MN Mobile Node CN Correspondent Node AR Access
Router
3. Start DAD
23
Optimistic DAD (cont)
MN Mobile Node CN Correspondent Node AR Access
Router
Prohibit unsafe communications
Allow safe communications
DAD in progress
24
Optimistic DAD (cont)
MN Mobile Node CN Correspondent Node AR Access
Router
Allow all communications
DAD is done
25
Hierarchical Mobile IPv6
MN Mobile Node CN Correspondent Node HA Home
Agent AR Access Router MAP Mobility Anchor
Point LCoA Link CoA RCoA Regional CoA
RCoA
LCoA
26
Hierarchical Mobile IPv6 (cont)

• Micro-mobility (with domain)
• MN obtains new LCoA from new AR
• RCoA remains the same
• No HA/CN binding update is needed
• Macro-mobility (between domains)
• MN obtains new LCoA from new AR
• MN obtains new RCoA from new MAP
• HA/CN binding update for the new RCoA is required

27
Fast Handover
Obtaining Prospective New CoA
MN Mobile Node CN Correspondent Node PAR
Previous Access Router NAR New Access
Router PCoA Previous Care-of Address NCoA New
Care-of Address
3. Form NCoA and use it for sending packets
28
Fast Handover (cont)
Establishing Tunnel
MN Mobile Node CN Correspondent Node PAR
Previous Access Router NAR New Access
Router PCoA Previous Care-of Address NCoA New
Care-of Address
29
Fast Handover (cont)
Tunneling and Buffering
MN Mobile Node CN Correspondent Node PAR
Previous Access Router NAR New Access
Router PCoA Previous Care-of Address NCoA New
Care-of Address
30
Fast Handover (cont)
31
Stealth-time HMIP

• Goals
• To improve handoff performance for
  macro-mobility.
• To reduce packet loss during handoff.

32
Stealth-time HMIP (cont)

• Key ideas
• Time for DAD is a dominant term in handoff delay.
• Overlap the operations of RCoA DAD and external
  binding update.
• Switching between one-layer IPv6 (LCoA only) and
  two-layer IPv6 (both LCoA and RCoA) addressing.
• Pre-handoff request to previous MAP for buffering
  packets.

33
MN Mobile Node MAP Mobility Anchor Point
pMAP Previous MAP AR Access Router CN
Correspondent Node HA Home Agent
MN
MAP
AR
HA/CN
pMAP
IP Layer
Link Layer
(1)
(2)
Link Layer Establishment
The Rendezvous Time
(3)
DAD form LCoA
34
MN
MAP
AR
HA/CN
pMAP
IP Layer
Link Layer
(4)
Registration with LCoA
One-layer Addressing
Registration with RCoA
(5)
DAD for RCoA
Two-layer Addressing
(6)
35
Stealth-time HMIP (cont)

• SHMIPv6 outperforms HMIPv6 in handoff delay.
• SHMIPv6 degrades gracefully.

36
A Novel Handover Scheme with Improved Performance
by Switching between Unicast Addressing and
Multicast Addressing

• Wei Kuang Lai 1, Chin-Shiuh Shieh 1,2, and
  Kai-Pei Chou 1
• 1 National Sun Yat-Sen University
• 2 National Kaohsiung University of Applied
  Sciences

37
Abstract

• An efficient handover scheme is essential for
  mobile networking.
• A novel scheme switching between unicasting and
  multicasting is proposed.
• A dedicated buffer control scheme is designed to
  reduce the possible packet loss and to prevent
  the out-of-order problem.
• Analytical study reveals that improved
  performance can be guaranteed, as reflected in
  the simulation results.

38
Introduction

• Ubiquitous networking aims at keeping connected
  at anywhere and at any time.
• Handover is the procedure that needs to be taken
  as a MN moving across different network domains
  to retain the continuation of ongoing services.
• Latency
• Packet loss

39
Introduction (cont)

• Handover can implemented at
• Application layer
• Transport layer
• Network layer
• Mobile IPv4
• Mobile IPv6
• Fast Handover Mobile IPv6
• Link layer

40
Introduction (cont)

• Duplicate Address Detection (DAD) dominates
  handover latency.

41
Related Works

• Tseng et al. 4 CN switches to bi-casting mode
  upon the reception of the binding update message
  from MN.
• Malki and Soliman 5 Let the previous AR to
  bi-cast received packets to both MN and the new
  AR.
• Takahashi et al. 6-7 Introduced a new
  network device, called Cross Router, for packet
  buffering and forwarding.

42
Related Works (cont)

• DAD dominates handover latency.
• Optimistic DAD.
• Fast Handovers for Mobile IPv6
• MN acquires new prospective CoA from a new access
  router prior to moving to that router.

43
Related Works (cont)
FHMIPv6 Obtaining Prospective New CoA
MN Mobile Node CN Correspondent Node PAR
Previous Access Router NAR New Access
Router PCoA Previous Care-of Address NCoA New
Care-of Address
3. Form NCoA and use it for sending packets
44
Related Works (cont)
FHMIPv6 Establishing Tunnel
MN Mobile Node CN Correspondent Node PAR
Previous Access Router NAR New Access
Router PCoA Previous Care-of Address NCoA New
Care-of Address
45
Related Works (cont)
FHMIPv6 Tunneling and Buffering
MN Mobile Node CN Correspondent Node PAR
Previous Access Router NAR New Access
Router PCoA Previous Care-of Address NCoA New
Care-of Address
46
Proposed Approach

• Multicast was adopted in our scheme as a radical
  approach for efficient handover.
• Let the system switch to multicast addressing
  during handover, and then switch back to normal
  unicast addressing after all required operations
  are done.
• Upon the Layer 2 triggering, the CN will be
  notified for switching to multicast mode.
  Meanwhile, MN and both new/old ARs will join the
  multicast tree rooted at the CN.

47
Proposed Approach (cont)

• Protocol Independent Multicast-Sparse Mode
  (PIM-SM) is preferred in our context.
• With data-driven PIM-SM, only those nodes
  explicitly joined the multicast group will
  receive packets from the source node.
• In general, due to geographic proximity, the join
  request from the new AR will reach an established
  multicast tree quickly.

48
Multicast-supported FMIPv6 (cont)
HA Home Agent CN Corresponding Node MN Mobile
Node NAR New Access Router PAR Previous Access
Router
CN
HA
Internet
PAR
NAR
49
(No Transcript)
50
Performance Analysis
51
Performance Analysis (cont)
52
Performance Analysis (cont)
53
Performance Analysis (cont)
54
Simulation

• Topology

55
Simulation (cont)

• Parameters

56
Simulation (cont)
57
Simulation (cont)
58
Simulation (cont)
59
Simulation (cont)
60
Conclusions

• Multicasting was integrated into our scheme as a
  radical solution to mask the most time-consuming
  DAD operation.
• Service disruption period can be substantially
  reduced by switching to multicast addressing
  during the handover.
• The proposed approach also minimizes the possible
  packet loss and the out-of-order problem.

61
A Novel Handover Scheme with Improved Performance
by Switching between Unicast Addressing and
Anycast Addressing

• Wei Kuang Lai 1, Chin-Shiuh Shieh 1,2, and
  Kuang-Ning Chu 1
• 1 National Sun Yat-Sen University
• 2 National Kaohsiung University of Applied
  Sciences

62
Abstract

• An efficient handover scheme is essential for
  mobile networking.
• A novel scheme switching between unicasting and
  anycasting is proposed.
• A dedicated buffer control scheme is designed to
  reduce the possible packet loss and to prevent
  the out-of-order problem.
• Analytical study reveals that improved
  performance can be guaranteed, as reflected in
  the simulation results.

63
Anycast-supported FMIPv6
HA Home Agent CN Corresponding Node MN Mobile
Node CR Cross Router NAR New Access
Router PAR Previous Access Router
CN
HA
Internet
CR
PAR
NAR
64
Introduction

• Ubiquitous networking aims at keeping connected
  at anywhere and at any time.
• Handover is the procedure that needs to be taken
  as a MN moving across different network domains
  to retain the continuation of ongoing services.
• Latency
• Packet loss

65
Introduction (cont)

• Handover can implemented at
• Application layer
• Transport layer
• Network layer
• Mobile IPv4
• Mobile IPv6
• Fast Handover Mobile IPv6
• Link layer

66
Introduction (cont)

• Duplicate Address Detection (DAD) dominates
  handover latency.

67
Related Works

• Tseng et al. 4 CN switches to bi-casting mode
  upon the reception of the binding update message
  from MN.
• Malki and Soliman 5 Let the previous AR to
  bi-cast received packets to both MN and the new
  AR.
• Takahashi et al. 6-7 Introduced a new
  network device, called Cross Router, for packet
  buffering and forwarding.

68
Related Works (cont)

• DAD dominates handover latency.
• Optimistic DAD.
• Fast Handovers for Mobile IPv6
• MN acquires new prospective CoA from a new access
  router prior to moving to that router.

69
(No Transcript)
70
Proposed Approach

• Anycast was adopted in our scheme as a radical
  approach for efficient handover.
• Let the system switch to anycast addressing
  during handover, and then switch back to normal
  unicast addressing after all required operations
  are done.
• MN is capable of receiving packets with anycast
  addressing during handover.

71
Proposed Approach (cont)

• Upon the Layer 2 triggering, the CN will be
  notified for switching to anycast mode.
  Meanwhile, MN and both CR/NAR will join the
  anycast tree rooted at the CN.
• Adding an anycast routing record to CR specifying
  PAR as its next hop is the only thing need to be
  done in our scheme.

72
Proposed Approach (cont)

• Advantages in using anycasting
• Extra overhead resulted from duplicated packet
  streams can be avoided
• Handover latency due to the time-consuming DAD
  operation can be effectively eliminated

73
(No Transcript)
74
Empirical Study

• Topology

75
Empirical Study (cont)

• Parameters
• Wireless MAC 802.11b
• Bandwidth of wired network 100M bps
• Router Advertisement interval 50 100 ms
• NAR DAD time 1 s
• Layer 2 handover latency 100 ms
• Link delay between routers 10 ms

76
Empirical Study (cont)
77
Empirical Study (cont)
78
Empirical Study (cont)
79
Performance Analysis
80
Performance Analysis (cont)
81
Performance Analysis (cont)
82
Conclusions

• Anycasting was integrated into our scheme as a
  solution to mask the most time-consuming DAD
  operation.
• Service disruption period can be substantially
  reduced by switching to anycast addressing during
  the handover.
• The proposed approach also minimizes the possible
  packet loss and the out-of-order problem.

83
Service Migration

• Service migration
• Migrate an ongoing service to new nearest server
  for topology change or node mobility
• Individual user can receive better service
• Global network may have better utilization

84
Service Migration (cont)

• Without service migration

S0
S4
S3
S2
S1
S5
R0
R4
R3
R2
R1
R5
85
Service Migration (cont)

• More delay and packet loss as hop count get
  increased.

86
Service Migration (cont)

• With service migration

S0
S4
S3
S2
S1
S5
R0
R4
R3
R2
R1
R5
87
Service Migration (cont)

• System Architecture

88
Service Migration (cont)

• Tasks for service migration
• Process migration
• Connection migration
• Specialized, dedicated, light-weighted service
  migration scheme to replace those
  general-purpose, heavy-weighted process migration
  techniques

89
Service Migration (cont)TCP-based Services
CN Client Node PPS Previous Proximity
Server NPS New Proximity Serve REQ_SM Request
for Service Migration REQ_PCM Request for
Process/Connection Migration SM_ACK Acknowledge
for Service Migration PCM_ACK Acknowledge for
Service Migration
NPS
CN
PPS
2. Suspend Process Extract Information
4. Create Process/Socket Copy Information
90
Service Migration (cont)TCP-based Services

• Implementation configuration
• Server end CentOS 4.5 (Linux Kernel 2.6.11), TCP
  Connection Passing v11, and gcc 3.4.6
• Client end Microsoft Windows XP2, WinpkFilter
  v3.0 and Microsoft Visual BASIC 6.0

91
Service Migration (cont)TCP-based Services
92
Service Migration (cont)UDP-based Services
CN Client Node PPS Previous Proximity
Server NPS New Proximity Serve REQ_SM Request
for Service Migration REQ_PCM Request for
Process/Connection Migration SM_ACK Acknowledge
for Service Migration PCM_ACK Acknowledge for
Service Migration
NPS
CN
PPS
7. Delete Process
93
Service Migration (cont)UDP-based Services

• Implementation configuration
• Microsoft Windows XP SP2
• Borland C Builder 6 Fix 4
• Winsock API and Indy UDP component
• Real-time Transport Protocol (RTP)

94
Service Migration (cont)UDP-based Services