Transcript Fast-handoff Mechanisms for Wireless Internet Presenter - Ashutosh Dutta 04/12/2005 IRT Group Meeting

Fast-handoff Mechanisms for Wireless Internet
Presenter - Ashutosh Dutta
04/12/2005
IRT Group Meeting
[email protected]
Outline
 Motivation
 Handoff Delay during Wireless Internet Roaming
 Related Work
 Multi-Interface/Inter-Technology Handoff
 Experimental Results
– MIP-based, SIP-based (binding)
 Proposed Ways to Optimize the handoff
– Multi-interface mobility management
– Proactive Handover
– SIP-based fast-handoff
– Proxy-based handoff for multicast stream
IRT Talkl - 2
Motivation
 It is desirable to limit the jitter, delay and packet loss
for VoIP and Streaming traffic
 150 ms end-to-end delay for interactive traffic such
as VoIP, 3% packet loss is allowed
 Delay due to handoff takes place at several layers
– Layer 2 (handoff between AP), Layer 3 (IP address
acquisition, configuration) and Media Redirection
 Rapid handoff will contribute to overall delay and
packet loss
 Thus it is essential to reduce the handoff delay
introduced at different layers
 We propose several mechanisms to reduce the
handoff-delay and packet loss
IRT Talkl - 3
Mobile Wireless Internet: A Scenario
Domain1
Internet
Domain2
PSTN gateway
WAN
802.11a/b/g
WAN
UMTS/
CDMA
IPv6
Network
802.11 a/b/g
Bluetooth
LAN
PSTN
Hotspot
LAN
PAN
Roaming
User
CH
UMTS/CDMA
Network
Ad Hoc
Network
IRT Talkl - 4
SIP-centric Wireless Internet Roaming
Public AAA
Home Domain
Visited
Domain
Public
SIP Server
AAA
Visited Registrar
AAA
Home
VR
QoS
QoS
HR Registrar
SLA/SA
SIP Server
SIP Server
Corresponding Host
DHCP/PPP
DHCP/PPP
DNS
PANA
PANA
N1
BS
ERC
128.59.11.6
BS
D
128.59.10.6
Interne
t
DNS
N2
N1
IPch
ERC
207.3.232.10
AP
ERC
N2
207.3.240.10
N1- Network 1 (802.11)
AP
N2- Network 2 ( CDMA/GPRS)
ERC - Edge Router and
Controller
AP
B
SIP
A enabled
MN
207.3.232.10
C
IRT Talkl - 5
Trajectory of a Packet
Source
Transmission
+ Handoff
Receiver
Total E-E delay = ∑T i
PCM
sample
T1
Total Packet Loss = PN – P1
Compressed
packet
T1 = Encoding Delay
T2 = Packetization Delay
T3 = Transmission Delay
T4 = Handoff Delay
T5 = Jitter buffer delay
T6 = De-Packetization delay
T7 = Decoding Delay
VoIP
Packet
T2
P1
Time
T3
P1
T4
T5 = 0
P1
T5
Lost
Packets
PN
T5
No
handoff
P1
T6
P1
PN
T7
T6
P1
PN
Handoff
T7
VoIP PN
Packet (Application)
IRT Talkl - 6
Handoff Latency
Dual mode
MN
DHCP server
PPP
AP1
AP2
Next VPN
Access GW
Router
HA/SIP Server
AAA
Server
Binds to AP1
Layer 2 Security

1
Layer 2 Association
Router Advertisement

3
2
Media
1
CN
1- L2 Hand-over Latency Delay
DHCP/PPP
2
2 – Delay due to
IP Address Acquisition and
Configuration, authentication, authorization
Stateless Auto-configuration
DAD/ARP
VPN
AAA
3
3 – Binding update and
Media Redirection delay
IGMP/RTCP
Binding Update
New Media
IRT Talkl - 7
Sample Delays (L3, L2)
L3 Delay
Method
(Linux)
DHCP
ARP w/o
Time
2
4-5 300
150 ms
400
s
ms
DRCP
DHCP (v6)
SA
160
ms
SF
500
ms
Auto
IP
Static
PPP
FA
COA
Proactive
IP
7-8
s
1–2
s
4-5
s
100 ms
Under
study
L2 Delay
H/W - OS
L2 Handoff
AiroNet +Linux
200 – 300 ms
Orinoco+Linux
100 – 160 ms
DLink +Linux
400 – 600 ms
Centrino + Linux
(Passive)
300 ms
Orinoco +Windows
250 ms
Hostap (Managed)
14 ms
IRT Talkl - 8
Mobility Optimization - Related Work
 Cellular IP, HAWAII - Micro Mobility
 MIP-Regional Registration, Mobile-IP low latency, IDMP
 HMIPv6, FMIPv6 (IPv6)
 Yokota et al - Link Layer Assisted handoff
 Shin et al, Velayos et al - Layer 2 delay reduction
 Gwon et al, - Tunneling between FAs, Enhanced Forwarding PAR
 DHCP Rapid-Commit, Optimized DAD - Faster IP address acquisition
 DFA, MOM (Multicast)
IRT Talkl - 9
Possible Handover Scenario
 Handover between 802.11 and 802.3 networks
 Handover between 802.3 and 802.16 networks
 Handover between 802.11 and 802.16 networks
 Handover between 802.11 and 802.11 networks,
across ESSs.
 Handover between 802.3 and Cellular networks
 Handover between 802.11 and Cellular
networks
 Handover between 802.16 and Cellular
networks
IRT Talkl - 10
Single Radio Interface Roaming Scenario
Provider A
Subnet A1(or ESS A1)
IEEE 802.11 LAN
Subnet A2(or ESS A2)
IEEE 802.11LAN
Intra-domain
Inter-subnet MIH
Subnet B1 (or ESS B1)
Provider B
IEEE 802.11LAN
Inter-domain
Inter-subnet MIH
IRT Talkl - 11
Handoff with Single Interface (802.11-802.11)
Example
Network 1 (802.11)
MN
Assign
IP0 to
Physical
I/F
AP1
R1
AP2
Network 2 (802.11)
Network 3
R2
CN
DHCP
Data
L2 handover
MN
-
DHCP
Packet
loss period
Assign PANA/AAA
IP1 to
Physical
SIP Re-invite with IP1
I/F
Data
IRT Talkl - 12
Multiple Radio Interface Roaming Scenario
Cellular Network
(CDMA/GPRS)
IEEE 802.11LAN
IEEE 802.11 LAN
WLAN: Activated
Cellular: deactivated
The mobile detects
Cellular starts the
connection, WLAN:
deactivated
Mobile
Detects
802.11
may disconnect
cellular
IRT Talkl - 13
Effect of handoff delay on audio (Non-Optimized)
802.11
CDMA
Handoff
19 s
802.11
Figure 3. Multiple Interface Case (802.11b – CDMA1XRTT) – MIP as mobility
802.11
CDMA
Handoff
17 s
802.11
Figure 3. Multiple Interface Case (802.11b – CDMA1XRTT) – SIP as mobility
802.11
Handoff
802.11
4s
Figure 1. Single Interface Case (802.11b – 802.11b) – SIP as mobility
IRT Talkl - 14
SIP-based subnet and domain Mobility handoff
(Experimental Results)
Handoff timing with more granularity
CH
Old IP address
IP1
RTP to IP1
Voice
20 msec
time interval
CH
MH
X
RTP to IP1
MH
RTP1
Time
Sec
Handoff
RTP1
59.521 - 10.1.4.162
00.478
(L2+DRCP+PANA)
X
RTP2
Re-Invite
New IP
00.652
address IP2
OK
Pr
Pr
00.701
00.759 - 10.1.1.130
00.938
ACK
Pr
RTP2
RTP to IP2
00.949
Fig 1. Handoff Factors for SIP-based mobility
PANA
Table 1. subnet/domain handoff
Experimental values
Operation
DRCP
2
Subnet
Handoff
79 ms
Domain
Handoff
81 ms
PANA
SIP
3
3
2 ms
228
ms
45 ms
289
ms
00.960
01.031
Media
(De-REG+REG) (01.049, 01.052)
RTP

Pr
OK
1490
ms
1656
ms
01.151
ACK
Pr
Pr = 220 ms
01.37
RTP1
01.52 – 10.1.1.130
IRT Talkl - 15
Inter-domain Secured Mobility
Domain1 (Home network)
Domain2 (Foreign network)
Pre-shared key
for alice@domain1
DIAMETER Server
DIAMETER Server
(AAA Foreign)
(AAA Home)
Temp. key
for alice@domain1
SIP Proxy
3
SIP Proxy
DIAMETER Client
PANA Agent
w/Firewall
DRCP
IPSec
AP
2
DIAMETER Client
PANA Agent
w/Firewall
DRCP
IPSec
Temp. key
for alice@domain2
CH
AP
RTP Key
Mobile Station
MN
5 Re-INVITE
1
Register
302
Moved
4 INVITE
PANA Client
NAI=alice@domain1
MN
RTP Key
IRT Talkl - 16
Effect of multilayer security on handoff - SIP-MIP
SIP-DRCP-PANA-AAA-IPSEC
Media Interruption – 1.31 sec
207.3.232.156
CH
MH
MIP-DRCP-PANA-AAA-IPSEC
Media Interruption – ~ 7 s
207.3.232.156
CH
MH
RTP1
RTP1
RTP1
RTP1
Time
Sec
RTP2
V
DISCO
DRCP
ER
51.756 – 10.1.4.162 (domain1)
52.066
52.146
TIME
(Sec)
RTP2
ISCOVE
DRCP D
R
DRCP OFFER
DRCP ACK
DRCP OFFER
52.176
ACK
52.226
52.266 – 10.1.1.130 (domain2)
24.216
24.246
52.276
52.346
IKE
ISAKMP
28.256
29.356
52.666
Mobile IP
RTP1
Pr
OK
ACK
Pr
24.156
24.176
24.196 – 10.1.1.130
PANA-AAA
PANA-AAA
ITE
ReINV
23.806 – 10.1.4.162
24.046
24.086
52.796
Pr
52.906
29.376
RTP1 (IPIP)
31.186 – 10.1.1.130
RTP1
53.066 – 10.1.1.130
Fig 3a. MIP-based secured Inter-domain mobility
handoff timing
Fig 3b. MIP-based secured Inter-domain mobility
handoff timing
IRT Talkl - 17
Need for fast-handoff (An example)
CN
Control signal
New data
Home
Domain
Transient data
Home SIP
Proxy
Public SIP Proxy
- Round trip time from
London to Sydney
is 540 ms, 28 hops
-London – Berkley
Is 136 ms, 22 hops
Public SIP Proxy
Transient
Data
Public SIP Proxy
RTP
Media after
Re-Invite
Internet
OK ACK
Visited Domain
Visited
Proxy/Outbound
SIP server
IP0
Subnet
MN S0
Move
Register
1
IP1 Translator
MN Subnet
S1
Translator
IP2 Subnet
MN S2
Move
IRT Talkl - 18
Fast-handoff mechanisms
Key Design Principles:
– Limit the signaling due to Intra-domain Mobility
– Capture the transient packets in-flight and redirects to the mobile
– Obtain IP address proactively and send binding update in the previous
network
– Make-before-break in multi-interface case
– Communicates proactively with CH before the handoff takes place by doing
pre-authentication
– Have a proxy joins the multicast stream on behalf of the impending client
 Methods currently experimented
– SIP Registrar and Mobility Proxy-based
– Proactive secured handoff (MPA)
– Proxy-based handoff for Multicast Streaming
 Other SIP-based fast-handoff methods for comparison
– Outbound SIP proxy server and mobility proxy
– B2BUA and midcom
– Multicast Agent
IRT Talkl - 19
SIP fast-handoff mechanism using mobility proxy
Outbound
Server
CH
MH
IP1
Visited SIP
Registrar
Mobility
Proxy
Subnet 1
Mobility
Proxy
Subnet 2
Mobility
Proxy
Subnet 3
Delay
Box
Media (1)
First move
Re-INVITE (2)
REGISTER 2’
IP2
(New Address)
SIP-CGI (3)
Transient
Traffic during
the move
IP2
Second move
Forward
traffic
(IP1:p1 ---> IP2:p1)
New traffic
Re-INVITE
IP3
(New Address)
Re-REGISTER
Transient
Traffic during
the move
Forward
traffic
(IP2:p1 ---> IP3:p1)
IRT Talkl - 20
Heterogeneous Mobility
(Host-based)
MIP HA
Corresponding Host
Data,
Video Stream,
Voice
Home Network
Router/MIP FA
R
Testbed
Core Network
Visited Network A
Ether
Bridge
802.11
AP
Laptop or PDA
Internet
Router/MIP FA
R
Visited Network B
BT
AP
MIMM
Cellular
Network
(cdma2000,
GPRS)
802.11
AP
MIMM
Visited Network C
MIMM
MIMM provides innovative techniques and algorithms to support
• Fast handoff among heterogeneous radio systems
• Fast and resource-efficient path quality comparison to allow terminal to pick the
interface that best fits is applications’ QoS needs at the lowest power consumption
IRT Talkl - 21
Multi-Interface Mobility Management - Results
MN
CH
Packet Sequence Number
INVITE with new IP address
200 OK
ACK
(500 packets/grid)
MIMM decide switching interface
3G Cellular
802.11b
RTP/UDP session destined to
the new Interface
Time (10 seconds/grid)
(a) handoff signaling sequence in SIP mobility
Figure 1: SIP-based Mobility with MIMM
MN
HA
MIMM decide switching interface
RRQ with life time = 0 for old addr
RRP with life time = 0 for old addr
RRQ with life time > 0 for new addr
RRP with life time > 0 for new addr
RTP/UDP session forwarded
to the new Interface
(b) handoff signaling sequence in Mobile IP
CH
RTP/UDP
session
destined to
Home address
HA stops
forwarding
packet in
this
duration
802.11b –
Cellular
Movement
type
Cellular802.11b
Handoff
Trials
#1
#2
#1
#2
INVITE -> OK
0.12 s
0.12 s
1.32 s
6.64 s
INVITE ->
1st Packet
0.39 s
0.41 s
2.54 s
7.18 s
Re-transmission
None
None
Yes
Yes
Figure 2: Timing for SIP-based Mobility
IRT Talkl - 22
SIP Mobility (without make-before-break) 802.11-CDMA
MN
eth0 22.733
CN
RTP 59961
RTP 59962
eth0 22.772
RTP 59963
Packets sent at 40
ms interval
eth0 22.812
Delay
18 s
PPP
Setup
~16 s
WLAN is gone
PPP0 is coming up
CN – 165.254.55.2
MN – WLAN – eth0 – 10.1.10.2
CDMA – PPP0 – 166.157.12.179
Re-INVITE
ppp0 38.453
Re-INVITE (Re-trans)
ppp0 38.965
ppp0 39.759
ppp0 39.878
ppp0 40.769
OK
ACK
RTP 60402
RTP 60403
Jitter
In cellular
network
ppp0 40.869
ppp0 40.969
RTP 60404
RTP 60405
ppp0 41.719
ppp0 41.729
RTP 60406
Packets sent at 40
ms interval
IRT Talkl - 23
SIP Mobility (MIMM) – Make-before-break (802.11 – CDMA)
CN
MN
RTP (28790)
(eth0) 16.202
Re_INVITE (IP1)
(ppp0) 16.240
RTP (28791)
(eth0) 16.242
(ppp0) 16.750
Re-INVITE (Re-trans) –IP1
•Jitter observed in Cellular
Network
-Several Re-INVITE retransmission
in CDMA network
-Packets are received in eth0 during
SIP Re-INVITE sequence
- No packets are lost during the handoff
RTP (28792)
(eth0) 16.285
(eth0) 16.322
RTP (28793)
RTP (28794)
(eth0) 16.362
(ppp0) 17.761
MN: WLAN - Eth0 – 10.1.10.2
CDMA - PPP0 – 166.157.116.186
CN – 165.254.55.2
Re_invite (Re-trans)- IP1
RTP
(eth0)
(eth0)
(ppp0) 19.639
(eth0)
Handoff
delay
(ppp0) 19.758
(eth0)
(eth0) 20.122
(ppp0) 20.549
(ppp0)
(ppp0)
20.669
20.769
20.869
RTP
OK
RTP
ACK
RTP
RTP 28888
RTP 28889
RTP 28890
IRT Talkl - 24
Mobility with VPN
Internal (protected)
External (unprotected)
CN
i-HA
Internal
Home
Network
MN
i-MIP tunnel
Internal
Visited
Network
MN
VPN
GW
External
Network 1
x-HA
VPN tunnel
External
Network N
x-MIP tunnel
DMZ
MN
MN
Based on its current location, MN dynamically establishes/changes/terminates tunnels
without changing current standards of IPsec VPN or Mobile IP.
Triple encapsulation tunnel is constructed by:
•
•
•
i-HA (Internal Home Agent): Forwards IP packets to MN’s current internal location
VPN GW: Protects (encrypts and authenticates) IP packets transmitted in external networks
x-HA (External Home Agent): Forwards IP packets to MN’s current external location
IRT Talkl - 25
Demonstration Scenario
Step 1: MN (at its home network over WLAN) and CN start an application
session, then MN starts moving
DMZ
VPN
GW
CN
x-HA
External
Network
(Cellular)
i-HA
Internal Home Network
(WLAN)
External (unprotected)
Internal (protected)
MN
MN
MN
IRT Talkl - 26
Demonstration Scenario
Step 2: MN starts preparing alternate path by establishing x-MIP and VPN
tunnel over the cellular link, while keeping communication via the home
network over WLAN
DMZ
VPN
GW
x-HA
VPN tunnel
CN
x-MIP tunnel
External
Network
(Cellular)
i-HA
Internal Home Network
(WLAN)
External (unprotected)
Internal (protected)
MN
MN
MN
IRT Talkl - 27
Demonstration Scenario
Step 3: MN stops using its home WLAN, starts using cellular and
establishes i-MIP tunnel, then continues communication with CN
DMZ
VPN
GW
x-HA
VPN tunnel
x-MIP tunnel
i-MIP tunnel
CN
External
Network
(Cellular)
i-HA
Internal Home Network
(WLAN)
External (unprotected)
Internal (protected)
MN
MN
MN
IRT Talkl - 28
Mobile-IP with VPN Experimental Testbed
Earth Link DSL
External
Hotspot
Internet
MN
External
Cellular
Verizon
CDMA 1XRTT
Enterprise Firewall
65
VPN
HoA = 70-75
GW
66
100
(99)
Internal Home
(SSID=ITSUMO home) i(demo.tari.toshiba.com) HA
MN
2
Linux
R
HoA = 210-215 1
AP
3
DNS
67
98
10.1.10.0/24
DMZ Network
Internal Visited
SIP
CH
X-HA
TIA = 111-120
.66 - .94
Monitor
205.132.6.64/27
4
10.1.20.0/24
DHCP
IRT Talkl - 29
Step-by-step protocol flow
CN
MN
i-HA
VPN-GW
x-HA
i-MIP Reply
i-HA
VPN-GW
RTP
RTP
SNR = S1
MN
CN
i-MIP Request
x-MIP Request
ESP + x-MIP
Make
Before
Break
CDMA
PPP
Connection
setup
ESP
SNR=S2
i-MIP Request
i-MIP Reply
ESP
x-MIP Reply
Data
on
802.11
x-HA
ESP + x-MIP
ISAKMP + x-MIP
RTP
ISAKMP
UDP + i-MIP
ISAKMP
ESP
ISAKMP + x-MIP
…
…
Data
Over
CDMA
(tripple
Tunneled)
ESP + x-MIP
…
…
PPP setup over CDMA at SNR (S1)
CN
Make-before-break
MN
i-HA
VPN-GW
…
…
scenario
at SNR = S2
x-HA
i-MIP Request
RTP
MN
Back
home
Data
On
802.11
i-MIP Reply
VPN
Tunnel
Teardown
ISAKMP + x-MIP
ISAKMP
Out-of-order
Transient
packets
ISAKMP
ISAKMP + x-MIP
1xrtt
Disconnection
…
…
Mobile coming back home
IRT Talkl - 30
Non-make-before-break situation
RTP Sequence
RTP Sequence
Non-Make-before-break
35000
34500
34000
33500
33000
32500
32000
31500
Non-make-before-break
802.11
(enterprise)
Cellular
802.11
(enterprise)
0
50
100
Packet Loss
Due to Non-make-before-break
150
200
250
300
Time in Seconds
IRT Talkl - 31
SUM (make-before-break)
802.11-Cellular Secured Handoff
RTP Packet
Sequence
2600
2500
2400
2300
2200
2100
2000
1900
1800
RTP sequence during
handoff
802.11(enterprise)
Cellular
Out-of-order-packet
802.11(enterprise)
0
20
40
60
80
100 120 140 160 180
Time in Seconds
IRT Talkl - 32
Home-cellular-Hotspot
Home-Cellular-Hotspot handoff
RTP Sequence
RTP Sequence
5500
Hotspot
802.11
4500
3500
2500
Cellular
External
1500
Home
802.11
500
0
100
200
300
400
Time in Seconds
IRT Talkl - 33
Handoff and delay with multiple Interfaces (MIPMobile IP with VPN
VPN)
Packet Transmission Delay for Voice Traffic
Transmission Delay
Timing
PPP setup
10 sec
X-MIP
300 ms
VPN Tunnel
setup
6 Sec
I-MIP
400 ms
I-MIP (Home)
200 ms
IPSEC
60 ms
DHCP
3 Sec
TransmissionDelay
5 ms 802.11
2.5 s cellular
63620
62280
60940
56933
52624
49317
45586
43252
41820
40480
39140
0.10000000
37800
1.00000000
36460
Transmission Delay in (Log Scale)
Packet Numbers
Operation
0.01000000
0.00100000
0.00010000
0.00001000
802.11
802.11
0.00000100
Cellular
0.00000010
(a) Packet Transmission Delay
Inter-Packet Delay Variation betw een CH and MH (Voice)
Packet Num bers
In ter-Pa c ket D ela y v aria tion b etwe en C H an d M H (Vid e o)
8 02 .11b
0 .1 00 0 0 0
24197
24166
24135
24104
24073
24042
24011
2 39 80
23949
23918
23887
23856
23825
23794
23763
23732
23697
2 366 6
23635
23604
23573
23542
23511
23480
23449
1 .0 00 0 0 0
62900
61876
60852
58279
54172
51671
48867
46019
44012
42604
41580
40556
39532
38508
37484
36460
1.0000
P a ck e t N u mb e r
23418
Inter-Packet Delay Variatio n (Log Scale)
C e llular
Inter-Packet Delay difference
(log scale)
1 0 .0 00 0 0 0
802 .1 1b
Delay Variatio n
10.0000
Inte r D iff
0 .0 10 0 0 0
0 .0 01 0 0 0
(c) Inter-packet departure and arrival delay variation for
VBR (Voice)
802.11
802.11
0.1000
0.0100
0.0010
(c) Inter-packet departure and arrival delay variation for
CBR (Voice)
IRT Talkl - 34
MOBIKE-flow (802.11-Cellular-802.11)
VPN traffic in 802.11
CN
MN
VPN GW
RTP
Tunnel (RTP)
VPN traffic in cellular
Mobike in cellular
Visited Network 1
(802.11)
Mobike in 802.11
IP0 – address of 802.11 interface
IP1 – address of cellular interface
IP0 is primary address
MOBIKE
44.948 (PPP is up)
Visited Network 2
(Cellular)
45.232 (Last packet on 802.11)
MOBIKE
45.522
MOBIKE
IP1 is primary address
Make-before-break
No packet loss
46.312 (First packet on Cellular)
46.432
46.469
28:44.091
51.894 (802,11 is primary interface)
MOBIKE
51.915
28:52.019
Visited Network
Packet
(802.11)
Loss
(Break-before-make)
IP0 is primary address
1
MN moves from 802.11 (hotspot) to Cellular to 802.11 (hotspot)
IRT Talkl - 35
MOBIKE-flow (Cellular-802.11-Cellular)
CN
VPN GW
RTP
VPN traffic in 802.11
MN
VPN traffic in cellular
Mobike in cellular
Tunnel (RTP)
Visited Network 1
(Cellular)
Mobike in 802.11
IP0 – address of 802.11 interface
IP1 – address of cellular interface
IP0 is primary address
MOBIKE
13.342 ( 802.11 is up)
Visited Network 2
(802.11)
MOBIKE
13.377
13.554 (First packet on 802.11)
IP1 is primary address
No packet loss
Out-of-order-packet
(make-before-break)
13.667 (Last packet on cellular)
MOBIKE
MOBIKE
43.103 (Last packet on 802.11)
47.881
IP0 is primary address
51.519
51.977
Visited Network 1
Packet
(Cellular)
Loss
(No-Break-before-make)
MN moves from Cellular to 802.11 (hotspot) to Cellular
IRT Talkl - 36
MPA-assisted Seamless Handoff (a scenario)
MN-CA key
AR
MN-CA key Network 1
AA
AA
AP2
AP1
CA
CA
CTN
AR
CTN
Network 2
Mobile
Current
Network
CTN – Candidate Target Networks
TN – Target Network
TN
MN-CA key
AR
AP0
AA
CA
Network 3
CN
AP3
Information Service (e.g.,802.21) mechanism can help locate the
neighboring network elements in the candidate target networks (CTN)
IRT Talkl - 37
Functional Components of MPA
1) Pre-authentication/authorization
– Used for establishing a security association (SA) between
the mobile and a network to which the mobile may move
– L2 pre-authentication can also be enabled based on the
established SA
2) Pre-configuration
– Used for establishing contexts specific to the network to
which the mobile may move (e.g., nCoA)
– The SA created in (1) are used to perform secured
configuration procedure
3) Secured Proactive Handover
– Used for sending/receiving IP packets based on the preauthorized contexts by using the contexts of the current
network
IRT Talkl - 38
Network
GPRS
W-CDMA
GSM
cdma2000
L2info
AP-ID
802.16
Location
L3info
802.11-SSID
longitude
Latitude
IPv6
802.11
Civic-addr
L2Mobility
L2QoS
IPv4
Ciphering
L3QoS
802.11r
Cost
802.11e
standard
Auth
L2PreAuth
IPsec
802.11u
channel
KMP
PANA
UAM
802.21
IKEv1
L3Mobility
IKEv2
KMP
11i4w
Cipher
AKM
phy
EP_addr
CT
AES-CCMP
Router_addr
CARD
MIPv4
L3Preauth
BSSID
PAA_addr
ISP_code
HA_addr
ISP_name
FA_addr
ISP_tariff
Psk
DHCP_addr
802.1x
Domain_name
subnet
VPN_server
Sip_server
WEP
Data_rates
Nsp_code
TKIP
Nsp_name
Nsp_tariff
Roaming
List
Expected Result
Detect
new AP
in different subnet
L3
L3 handoff
auth/authz
starts
L2 handoff starts
starts
Conventional
Method
Time
L3 handoff
L2 auth/authz,
completes
starts
L2 handoff L3 auth/authz
completes completes
Detect
new AP
Pre-auth/
Pre-authz
starts
L3 handoff
starts
L2 handoff
starts
MPA
Time
Pre-auth/
L3 handoff
Pre-authz
completes
Completes
(L2 SAs can be ,
completed here.)
L2 handoff
completes
Critical period (communication interruption can occur)
IRT Talkl - 40
Pre-Authentication
SIP mobility is just an example mobility
protocol. MPA works for any mobility
management protocol
CN
DATA[CN<->A(X)]
AA
Subnet X
CA
AR
Subnet Y
pre-authentication
MN
CN: Correspondent Node
MN: Mobile Node
AA: Authentication Agent
CA: Configuration Agent
AR: Access Router
IRT Talkl - 41
Pre-authorization
CN
DATA[CN<->A(X)]
MN-CA key
AA
CA
Subnet X
AR
Subnet Y
pre-authorization
MN
IP address: A(X)
Current subnet: X
Status: Pre-authentication done
Action: pre-authorization
CN: Correspondent Node
MN: Mobile Node
AA: Authentication Agent
CA: Configuration Agent
AR: Access Router
IRT Talkl - 42
Proactive Handover: Initial Phase
CN
DATA[CN<->A(X)]
MN-AR key
AA
CA
Subnet X
AR
Subnet Y
Secure Proactive
Handover tunnel
establishment
procedure
MN
IP address: A(X), A(Y)
Current subnet: X
Status: Pre-authorization done
Action: PH Initiation
CN: Correspondent Node
MN: Mobile Node
AA: Authentication Agent
CA: Configuration Agent
AR: Access Router
IRT Talkl - 43
Proactive Handover: Tunneling Phase
CN
DATA[CN<->A(X)]
MN-AR key
AA
CA
Subnet X
AR
Re-Invite[CN<->A(Y)]
Subnet Y
SIP Re-Invite over
proactive hanodver
tunnel [AR<->A(X)]
MN
IP address: A(X), A(Y)
Current subnet: X
Status: PH tunnel established
Action: SIP Re-Invite
CN: Correspondent Node
MN: Mobile Node
AA: Authentication Agent
CA: Configuration Agent
AR: Access Router
IRT Talkl - 44
Proactive Handover: Completion Phase
DATA [CN<->A(Y)]
over proactive hanover
tunnel [AR<->A(X)]
AA
Subnet X
CA
CN
AR
Subnet Y
Proactive handover
stop procedure
MN
IP address: A(X), A(Y)
Current subnet: X
Status: SIP Re-Invite done
Action: PH Completion
L2 handoff
procedure
CN: Correspondent Node
MN: Mobile Node
AA: Authentication Agent
CA: Configuration Agent
AR: Access Router
IRT Talkl - 45
MPA Communication Flow
Candidate Target Network
MN
nPoA
oPoA
CA
AA
AR
CN
Existing session using oCoA
1. Found CTN
Pre-authentication
[Authentication Protocol]
MN-CA Key
2. High probability to
switch to the CTN
MN-AR Key
Pre-configuration
[Configuration Protocol to get nCoA]
Pre-configuration [tunnel management protocol to establish PHT
3. Determined to switch to
The CTN
4. BU completion and
Ready to switch
5. Switching
Secure Proactive Update Phase
Binding Update + data Transmission over PHT using nCoA
Secure proactive handover pre-switching phase
[tunnel management protocol to delete PHT]
Post Switching Phase: Reassignment of nCoA to its physical Interface
New Data using nCoA
IRT Talkl - 46
MPA Optimization Issues
 Network Discovery
– Discover the neighboring network elements (e.g., Routers, APs,
Authentication Agents)
– 802.21 (Information Service), 802.11u, WIEN SG, CARD, DNS/SLP
 Proactive IP Address Acquisition
 Proactive Duplicate IP address Detection
 Proactive Address Resolution
 Proactive Tunnel Management
 Proactive Mobility Binding Update
 Bootstrap Link-layer Security in CTN using L3 Preauthentication
IRT Talkl - 47
Protocol Set for the MPA demonstration
Pre-authentication protocol
PANA
Pre-configuration protocol
PANA,
DHCP
Relay
Proactive handover tunneling protocol
IP-in-IP
Proactive handover tunnel management
protocol
PANA
Mobility management protocol
SIP Mobility
Link-layer security
None
IRT Talkl - 48
Experimental Network in the Lab.
Network 2
Network 1
10.10.20.52/24
10.10.20.52/24
10.10.40.52/24
R1
eth0
DHCP
Server
eth2
AA
PANA
Agent
eth0
AR
AR
R2
10.10.10/24
10.10.30/24
Relay/
Client
Proxy
IP2
DHCPCA
Server
AP1(Channel 6)
ITSUMO network
Network 3
SIP with VIC/RAT
Application
MN
AP2(Channel 9)
MN
10.10.10.51
CN
Move
IP0: 10.10.40.20
IP1: 10.10.10.223
10.10.30.25
AP1, AP2: Access Point
R1, R2: Access Router
MN: Mobile Node
CN: Correspondent Node
IP0, IP1: IP address of MN
IRT Talkl - 49
Protocol flow for MPA
Network 2 (802.11)
Network 1 (802.11)
MN
AP1
Assign DHCP
IP0 to
Physical
I/F
R1
AP2
R2
DHCP
Network 3
CN
Data
Assign
IP1 to
Tunnel
I/F
PANA (Pre-Authentication and pre-configuration to obtain IP1)
Address
acquisition
Using DHCP
relay
-
Tunnel (IP0-IP1)
SIP Re-invite
with IP1
Data
Deletes Tunnel with PANA Update
L2 handover
Packet
loss period
MN
Assign
Data
IP1 to
Physical
I/F
IRT Talkl - 50
MPA Experimental Flow (proactive handoff)
Signal
RTP Data
Lost RTP Data
Tunneled packet
MN
MN
Network 1
CN
DHCP
R2
Network 3
Network 2
RTP
IP0
DHCP
PANA
Tunnel
Setup
PANA (ACK)
DHCP(IP1)
RTP
RTP
SIP Re_INVITE (IP1)
8.913
OK (tunneled)
BU
No
Packets
lost
During BU
9.030
RTP packets
Spaced ~16 ms
RTP
9.136
9.267
OK
ACK
Tunneled Data
RTP (39835)
RTP (40335)
Handoff
Decision
Tunnel
deleted
19.283
19.285
PANA Trigger to delete tunnel
PANA Response
19.291
19.298
19.315
19.379
L2 handoff
19.393
+ local L3
19.394
Configuration 19.408
RTP (40336)
RTP (40337)
RTP (40340)
IWCONFIG (IOCTL)
19.395
X
JOIN
(Auth/Assoc, ifconfig, route,)
JOIN (ACK)
Lost packet (non-tunnel)
First packet in new network (non-tunneled)
RTP (40341)
RTP (40342)
19.411
IP1
IRT Talkl - 51
Optimized handoff delay (Single IF/ Multiple I/F)
802.11
4s
CDMA
802.11
4s
CDMA
Figure 3: Multi-Interface with MIP (802.11-CDMA)
802.11
CDMA
Figure 4: Multi-Interface with SIP (802.11-CDMA)
Figure 5: Proactive with SIP mobility (Single Interface 802.11-802.11)
IRT Talkl - 52
Fast-handoff for Multicast Stream (General Scenario)
Source
Home Network
MN
Multicast Tree
Internet
HA
DHCP
DHCP
MR1
MR2
Visited Network 2
MN
Visited Network 1
MN
Handover
IRT Talkl - 53
Multicast Mobility with multiple servers
Sources
p1
S1
S2
p2
Objective: Reduce Join/Leave Latency during
Mobile’s movement
M-Proxy
Backbone
S1
m1
S0
IGMP
• Fast-handoff for the
mobiles
Local
Server
m1
m2
Local
Server
RTSP
Local
Program
Ad server
m2
RTSP
Ad server
(a1,a2)
Local
Program
(a3)
BS0
(P1,a1)
(P2,a2)
RTCP
BS1
BS2
P2,a3
P2,a2
IRT Talkl - 54
IGMP Join/Leave latency vs. Proxy-based handoff in 802.11
environment
Layer 2 Handoff for Multicast
5
Protocols
4
RTP
DRCP
3
Router Query
Q.Response
2
1
Protocols Instance at Mobile
IGMP-802.11 (Subnet) Handoff
0
0
200
400
600
5
4
RTP
3
Subnet
handoff
Router Query
2
Q.Response
1
0
800
Ping-Pong
JOIN Latency
0
200
Ping-Pong
400
600
JOIN Latency
800
1000
TIme in Seconds
Time in Seconds
There is no JOIN Latency but Leave latency
inherent
JOIN Latency is about 60 seconds
Proxy assisted subnet handoff
LEAVE latency during 802.11subnet handoff
5
Leave
latency
5
4
4
RTP
3
DRCP
Router Query
2
Q.Response
1
Protocols
Protocols at mobile
DRCP
Subnet
handoff
3
RTP
DRCP
2
Router Query
Ping Mobile
1
0
0
200
400
600
Time in Seconds
JOIN latency is almost zero
Leave latency is still an issue
800
0
120
180
240
300
360
420
480
540
600
Timr in Seconds
Maximum leave latency is about 3 min.
IRT Talkl - 55
Conclusions
 Rapid Handoff in an IP-based cellular network has adverse effect for
interactive and streaming traffic
– Introduces delay, jitter and packet loss
 Experimental results were presented involving handoff between
homogeneous and heterogeneous access networks
– 802.11-802.11, 802.11 – CDMA
 Both SIP-based and MIP-based mobility were used for experiment
 Optimized Handoff Schemes were presented with some results for
each scheme
 Optimized handoff schemes seem to be more prominent for
– Proactive Handover
– When the distance between CH and MH is much larger
– Proxy-based handoff for multicast stream
 Future Work
– Comparison with other fast-handoff mechanisms
– Network Selection/Discovery Mechanism
– Buffering Scheme for MPA assisted handoff
IRT Talkl - 56