Title: Mobility Management in Wireless Environments
1Mobility Management in Wireless Environments
- Wei Kuang Lai (???)
- Department of Computer Science and Engineering
- National Sun Yat-sen University, Kaohsiung, Taiwan
2Outline
- Mobile Networking
- Mobile IPv4, Mobile IPv6
- Established Techniques
- Innovative Approaches
- Q A
3Mobile Networking
- Why Mobility?
- Seamless Handover and Challenges
- Handover Latency
- Mobile IPv4
- Mobile IPv6
4Establish Techniques
- Layer 2 Triggering
- Optimistic DAD
- Hierarchical Mobile IPv6
- Fast Handover
5Innovative 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
7Mobile 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
8Mobile 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
9Mobile 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,
10Mobile Networking (cont)
- Duplicate Address Detection (DAD) dominates
11Mobile 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
12Mobile IPv4 (cont)
Obtaining CoA
MN Mobile Node CN Correspondent Node HA Home
Agent FA Foreign Agent CoA Care-of Address
Obtain CoA
13Mobile IPv4 (cont)
Registering CoA
MN Mobile Node CN Correspondent Node HA Home
Agent FA Foreign Agent CoA Care-of Address
14Mobile IPv4 (cont)
Tunneling Triangular Routing
MN Mobile Node CN Correspondent Node HA Home
Agent FA Foreign Agent CoA Care-of Address
15Mobile IPv6
- Built-in mobility supports in IPv6
- Address auto-configuration
- Route optimization
- No need for Foreign Agent
16Mobile 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
17Mobile 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
18Mobile IPv6 (cont)
Triangular Routing
MN Mobile Node CN Correspondent Node HA Home
Agent AR Access Router CoA Care-of Address
19Mobile IPv6 (cont)
Bi-directional Tunneling
MN Mobile Node CN Correspondent Node HA Home
Agent AR Access Router CoA Care-of Address
Tunneling
20Mobile IPv6 (cont)
Direct Routing (Route Optimization)
MN Mobile Node CN Correspondent Node HA Home
Agent AR Access Router CoA Care-of Address
21Layer 2 Triggering (cont)
MN Mobile Node CN Correspondent Node AP Access
Point
Signal Strength
22Optimistic DAD
MN Mobile Node CN Correspondent Node AR Access
Router
3. Start DAD
23Optimistic DAD (cont)
MN Mobile Node CN Correspondent Node AR Access
Router
Prohibit unsafe communications
Allow safe communications
DAD in progress
24Optimistic DAD (cont)
MN Mobile Node CN Correspondent Node AR Access
Router
Allow all communications
DAD is done
25Hierarchical 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
26Hierarchical 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
27Fast 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
28Fast 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
29Fast 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
30Fast Handover (cont)
31Stealth-time HMIP
- Goals
- To improve handoff performance for
macro-mobility. - To reduce packet loss during handoff.
32Stealth-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.
33MN 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
34MN
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)
35Stealth-time HMIP (cont)
- SHMIPv6 outperforms HMIPv6 in handoff delay.
- SHMIPv6 degrades gracefully.
36A 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
37Abstract
- 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.
38Introduction
- 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
39Introduction (cont)
- Handover can implemented at
- Application layer
- Transport layer
- Network layer
- Mobile IPv4
- Mobile IPv6
- Fast Handover Mobile IPv6
- Link layer
40Introduction (cont)
- Duplicate Address Detection (DAD) dominates
handover latency.
41Related 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.
42Related 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.
43Related 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
44Related 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
45Related 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
46Proposed 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.
47Proposed 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.
48Multicast-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)
50Performance Analysis
51Performance Analysis (cont)
52Performance Analysis (cont)
53Performance Analysis (cont)
54Simulation
55Simulation (cont)
56Simulation (cont)
57Simulation (cont)
58Simulation (cont)
59Simulation (cont)
60Conclusions
- 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.
61A 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
62Abstract
- 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.
63Anycast-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
64Introduction
- 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
65Introduction (cont)
- Handover can implemented at
- Application layer
- Transport layer
- Network layer
- Mobile IPv4
- Mobile IPv6
- Fast Handover Mobile IPv6
- Link layer
66Introduction (cont)
- Duplicate Address Detection (DAD) dominates
handover latency.
67Related 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.
68Related 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)
70Proposed 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.
71Proposed 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.
72Proposed 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)
74Empirical Study
75Empirical 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
76Empirical Study (cont)
77Empirical Study (cont)
78Empirical Study (cont)
79Performance Analysis
80Performance Analysis (cont)
81Performance Analysis (cont)
82Conclusions
- 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.
83Service 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
84Service Migration (cont)
- Without service migration
S0
S4
S3
S2
S1
S5
R0
R4
R3
R2
R1
R5
85Service Migration (cont)
- More delay and packet loss as hop count get
increased.
86Service Migration (cont)
S0
S4
S3
S2
S1
S5
R0
R4
R3
R2
R1
R5
87Service Migration (cont)
88Service 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
89Service 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
90Service 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
91Service Migration (cont)TCP-based Services
92Service 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
93Service 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)
94Service Migration (cont)UDP-based Services