Post on 07-Mar-2018
transcript
IP-based Mobility and
Handover Optimization (T3)
Tutorial Authors:H. Anthony Chan, Ph.D.
Huawei Technologies, USA
anthonychan@huawei.com
Ashutosh Dutta, Ph.D.
NIKSUN Innovation Center, NJ, USA
adutta@niksun.com
Presented by Ashutosh Dutta
IEEE WCNC 2011Cancun, Mexico
– A name identifies what you want,
– An address identifies where it is,
and
– An route identifies a way to get there
John Shoch, 1978
Outline• Overview of Mobile Wireless Internet
• Mobility Taxonomy
• Systems modeling of mobility event
• Functional components of mobility event
• Overview of Mobility Protocols– Cellular Mobility Protocols
• GSM, IS-41, WCDMA, CDMA2000, LTE
– IP-based Mobility Protocols• MIPv4, MIPv6, ProxyMIPv6, HIP, SIP, DSMIPv6, DMM
•Handoff Optimization Methodologies– Optimization of mobility functions
– Optimization Models
Outline (contd.)• Applicability of Optimization Techniques to different Mobility Protocols
– L2 and L3 Discovery
– L3 Configuration Delay
– Network Detection Delay
– Authentication
– Security Association
– Route Optimization
– Hierarchical binding update,
– Redirection of in-flight data
– Small group multicasting
– Buffering and Copy-Forwarding Technique
• IEEE 802.21 Multi-interface Mobility – Media Independent Handover Functions (MIHF)
• Optimized Handoff Systems (Case studies)– Media Independent Pre-authentication– Multimedia Session Continuity in IMS-based systems– Multicast mobility
• Deployment roaming scenarios
• Petri net based mobility models
• Rules of mobility optimization
• Conclusions
L3 Attachment PointRAP
R
RR
AP
AP
AP
AP
AP
R
Domain
Router
R
RR
RR
Domain
Router
R AP
AP
AP
R
CH
AP
AP
AP
R
RR
AP
AP
AP
AP
AP
R
Domain
Router
R
RR
RR
Domain
Router
RAP
AP
AP
R
MH
AP
AP
AP
CORE
Router
L2 Attachment Point
CORE
Router
An abstract view of mobility
Abstract view of Host Mobility (Terminal Mobility)
A
B
C
Process
SOCKET
End-PointLocator
Process
SOCKET
End-PointLocator
X
Y
Z
PATH
NODE A NODE B
Process
SOCKET
End-PointLocator
Process
SOCKET
End-PointLocator
A
B
C
X
Y
W
PATH
NODE A NODE B
Node B moves
Application T
Application T
Process
SOCKET
End-PointLocator
Process
SOCKET
End-PointLocator
X
Y
Z
PATH
Host A Host B
Process
SOCKET
End-PointLocator
Process
SOCKET
End-PointLocator
A
B
D
X
Y
W
PATH
NODE A NODE B
Nodes A and B
Both move
Application T
Application TA
B
C
As an example
End-Point, Locator could be an IP address
Trajectory of a Packet (Source-Destination)
Source
PCM sample
CompressedpacketT1
T2
T3
T4
T5
T6
T7VoIPPacket (Application)
Receiver
Total E-E delay = ∑T i
Transmission+ Handoff
T1 = Encoding Delay
T2 = Packetization Delay
T3 = Transmission Delay
T4 = Handoff Delay
T5 = Jitter buffer delay (mobile)
T6 = De-Packetization delay
T7 = Decoding Delay
P1
P1
PN
T4 = 0
P1
T6
T7
P1
P1
P1PN
PN
PN
T5
Total Packet Loss = PN – P1
Time Nohandoff
Handoff
LostPackets
VoIPPacket
No handoff
Handoff
42 Mb/s (DL),
22 Mb/s (UL)
CDMA2000
NX
TACS
NMT
AMPS
SMR
GPRS EDGEGSM
IS-136
IS-95 (A)
iDEN
PDC
IS-95 (B)CDMA2000
1X
WCDMA
1 G 2 G 2.5 G 3 G 4 G
144 kb/s, 384
kb/s, 2 Mb/s
144 kb/s, 384
kb/s, 2 Mb/s
JTACS
54 kb/s 236 kb/s
144 kb/s
50 UL, 100 DL
9.6 kb/s
9.6 kb/s
48.6 kb/s
42 kb/s
NTT
24 kb/s
IEEE 802.16
802.20
EHSPA
UMB
LTE
80 Mb/s (UL), 360 Mb/s
280 Mb/s
80 Mb/s
115 kb/s
1980 1990 19952000
2008
Evolution of mobility protocols
Cellular Access CharacteristicsGeneration System Channel
spacing
Access type Uplink data
rate
1G AMPS 30 kHz FDMA N/A
TACS 25 kHz FDMA N/A
NMT 25 kHz FDMA N/A
NTT 25 kHz FDMA N/A
2G GSM 200 kHz TDMA 9.6 kb/s
PDC 30 kHz TDMA 42 kb/s
IS-136 30 kHz F/TDMA 48 kb/s
IS-95 (A) 1.25 MHz F/CDMA 14.4 kb/s
iDEN 25 kHz F/TDMA 24 kb/s
2.5G GPRS 200 kHz TDMA 45 kb/s
EDGE 200 kHZ TDMA 236 kb/s
IS-95 (B) 1.25 MHz F/CDMA 115 kb/s
CDMA2000 1X 1.25 MHz CDMA 144 kb/s
3G UMTS/WCDM
A
5 MHz CDMA/TD
MA
2 Mb/s
CDMA2000
1xEV-DO
1.25 MHz CDMA 2 Mb/s
4G LTE 20 MHz OFDMA 50 Mb/s
WiMAX 2.5 GHz OFDM 40 Mb/s
UMB 5 MHz OFDMA 75 Mb/s
MH
nPoAoPoABTS A
MSC
BSC 1
Serving
Cell
BSC 2
Target
Cell
VLRAUC
Move
EIR
BSS
nPoA nPoA
HLR
Cellular mobility – GSM – an example
BTS B BTS CBTS D
HLR – Home Location RegisterMSC - Mobile Switching Center
AUC – Authentication CenterBSC – Base Station ControllerBSS – Base Station SystemBTS – Base Transceiver StationEIR – Equipment Identity Register
VLR – Visitor Location Register
GSM Mobility
BSC
MSC
MS
BTS BTS
OLD NEW
Switching Point BSC
MSC
MS
BTS BTS
OLD NEW
Switching Point
BSC
OLD
OLD
NEW
NEW
Switching Point
BSC
MSC
MS
BTS BTS
OLD NEW
BSC
MSC
OLD
OLD
Anchor MSC Relay MSC
Switching Point
BSC
MSC
MS
BTS BTS
OLD NEW
BSC
MSC NEW
NEW
Relay MSC Relay MSC
MSCAnchor MSC
NEW
NEW
Switching Point
BSC
MSC
MS
BTS BTS
OLD NEW
BSC
MSC
OLD
OLD
Relay MSC Anchor MSC
Old Path
New Path
1. Intra BSC Handover 2. Inter BSC/intra-MSC Handover
3.Inter-MSC handover (anchor-to-relay)
4. Inter-MSC handover (relay-to-relay)
5. Inter-MSC handover (relay-to-anchor)
MH
nPoAoPoA
CDMA
BTS A
MSC
BSC 1
Serving
Cell
BSC 2
Target
Cell
HLR
Move
SMS-SC
CDMA
BTS B
AC
VLR
EIR
External
Network
PSTN
and
ISDN
IS95 (2G)IS95-based architecture
IS-41 Handoff (Mobile Assisted Handoff)
Serving
BS/MSC
Target
BS/MSC
Mobile
StationPilot Strength
Measurement
Message
(T_ADD)
Pilot Strength
Measurement
Message
(T_COMP)
Facilities Directive INVOKE
Facilities Directive
Return RESULT
Handoff Direction Message
Handoff Completion Message Mobile On-Channel
INVOKE
Searches
for Pilot (discovery phase)
Resource
Assignment
MH
nPoAoPoANode B
MSC/VLR
RNC1
Serving
Cell
RNC2
Target
Cell
HLRGGSN
Move
SGSN
RNS1
nPoA nPoA
GMSCPSTN/
ISDN
IP
Network
L3 PoA
RNS2SGSN
WCDMA architecture
Mobility State Model for GPRS/UMTS
IDLE READY STANDBY
GPRS
Attach
GPRS Detach/
RAU Reject/
GPRS Attach
Reject
READYTimer expiryForce to Stanbdy
PDU
transmission
PMMDETACHED
PMMIDLE
PMMCONNECTED
PS Attach PS SignalingConnectionRelease
PS SignalingConnectionEstablish
Implicit PS Detach
1. MS MM States for GPRS2. MS MM States for UMTS
IDLE READY STANDBY
GPRS
Attach
GPRS DetachRAU ReadyGPRS Attach Reject
READYTimer expiryForce to Stanbdy
PDU
Reception
PS Detach
RAU Reject
PS Attach Reject
PMMDETACHED
PMMConnected
STANDBY
PS
Attach
GPRS DetachRAU ReadyGPRS Attach Reject
READYTimer expiryForce to Stanbdy
PS Signaling
Connection Establish
PS Detach
RAU Reject
PS Attach Reject
Cancel Location
PS
Detach3. SGSN MM States for GPRS
4. SGSN MM States for UMTS
GPRS UMTS
Home Agent
BSC1 BSC2 BSC3 BSC4
PCF1 PCF3 PCF4
PDSN2PDSN1
PCF2
FA1FA2
MSC
PSTN
GMSC
HLR
AC
A B CD F
BTS1
E
L3 PoA L3 PoA
L2 PoA BTS3 L2 PoA
VLR
CDMA2000 architecture
Mobility State Model for CDMA
DORMANT
NULL/
INACTIVE
ACTIVE/
CONNECTED
MS Powers off
MS Powers ON
MS Powers off
Packet Data Inactivity,
Timer Expires
MS or network initiates packet
call reactivation
Source
eNB
Target
eNBCandidate
eNB
MME
Serving
Gateway
(S-GW)PDN-GW
UEUE
UE
SGSN
E-UTRAN
IP-basedIMS
network
Enhanced Packet Core (EPC)
UEUE
ePDG
Untrusted
Non-3GPP
Trusted
Non-3GPP
(WiFI, WiMAX)
UTRAN
SAE/LTE (4G)
HSSPCRF
SGiS5
S11
S1-U
S1-MME
S4
S7
S6a
S3
S2a
S2b
AAA
S6c
Wm
Wn
PCEP
Rx+
Wx
S10
X2
X2 X2
MME S-GWUE Source
eNBTarget
eNB
Data packets
Measurement
report
Handover request
Handover AckRRC
Reconfigure
Detach old
and
Sync new
Buffering
for
forwarding
Data forwarding
Buffer source
eNB packets
RRC Reconfiguration complete
Path switch
request
Modify bearerEnd-of-marker packets
Stops
forwarding
data
Status Transfer
UE context releaseModify bearer ACK
Path switch
Request ACK
Switch
DL
path
Release
resource End of marker
New Data packetsData packets
SAE Handoff
What are Characteristics of Next
Generation Networks?• Heterogeneous networks, many access networks
– Access-independent converged IP network
• Order-of-magnitude increases in bandwidth
– MIMO, smart antennas
– Increase in video and other high bandwidth traffic
• New terminals
• New services and service enabling platforms
• Large range of cell sizes, coverage areas
– PAN, LAN, WAN
– Pico-cellular, micro-cellular, cellular
• Changes in traffic and traffic patterns
– Rise in video on demand? Requires good high-bandwidth
multicast
One Vision of 4G
IP-BasedCore Network
Media Access SystemMedia Access System
Cellular(2G)
Cellular(2G)
Packet-Based
(2.5G)
Packet-Based
(2.5G)
IMT-2000(3G)
IMT-2000(3G)
WLANType
WLANType
New RadioInterface
New RadioInterface
Services &ApplicationsServices &
Applications
Fixed
Wireless
Fixed
Wireless
Services &ApplicationsServices &
Applications
Mobile Wireless Internet: A Scenario
802.11a/b/g
Bluetooth
IPv6
Network
UMTS/CDMA
Network
InternetDomain1
Domain2
UMTS/
CDMA
PSTN gateway
Hotspot
CHRoaming
User Ad Hoc
Network
PAN
LAN
WAN
WAN
LAN
PSTN
802.11 a/b/g
Backbone
Administrative
Domain B
L2 PoA
Corresponding
Host
128.59.10.7
IPch
207.3.232.10
210.5.240.10
128.59.11.8
N2
N1N1
N2
N1- Network 1 (802.11)
N2- Network 2 ( CDMA/GPRS)
Configuration
Agent
L3 PoA
207.3.232.10
MobileHost
AuthenticationAgent
Authorization Agent
RegistrationAgent
RegistrationAgent
Administrative
Domain A
Configuration
Agent
Authorization Agent
SignalingProxy
AuthenticationAgent
SignalingProxy
Layer 3
PoA
L2 PoALayer 2
PoA
Layer 2
PoAL3 PoA
Mobility Illustration in IP-based 4G network
128.59.9.6
L3 PoA
A
B
CD
900 ms media interruption
802.11 802.11
h/o delay900 ms
802.11 802.11
4 Seconds media interruption h/o delay 4 s
Handoff Delay~ 18 s
802.11 CDMA
18 Seconds media interruptionh/o delay18 s
23
Non-optimized handoff results
Handoff between heterogeneous access(802.11 – CDMA)
Handoff between homogeneous access(802.11 – 802.11)
c. SIP-based non-optimized
handoff between 802.11 networks
802.11 802.11Handoff
Delay 4 s
Handoff Delay
~ 18 s
802.11 CDMA
Handoff Delay
16 s
802.11 CDMA
a. MIP-based Non-optimized handoff
b. SIP-based Non-optimized handoff
Performance Degradation – Non-optimized
Handoff
Mobility TaxonomyIP Mobility
PersonalTerminal Service
Application
Layer
Network
Layer
Session
• Systems
Optimization
MIPv4 Cellular IPHAWAIIIDMP MIP-LR MIPV6ProxyMIPv6
SIPMM
MIP-LR(M)
Proxy
Transport
Layer
MSOCKS,
Migrate
mSCTP
Shim Layer
HIP
Issues
• Host controlledvs.
Mobile Controlled
• Mobility pattern
Several concepts of mobility• Terminal mobility, e.g., supported by Mobile IP
IP-based Network
CH
Subnet 1MH
Subnet 2
IP-based Network
CH
Subnet 1
MH
Subnet 2• Typically, you don’t
just have terminals
– Users/Persons
– Sessions
• Mobility of users, sessions?
Personal Mobility: Registration
IP-based Network
CH
Subnet 1
Subnet 2
registrar
IP-based Network
CH
Subnet 1
Subnet 2
registrar
• When lady in red moves, she
– leaves her laptop behind
– Uses another machine
– Logs in
• User registration performed
person@subnet1.org
person@subnet2.org
Personal Mobility: simultaneous
registration of multiple bindings
IP-based Network
CH
Subnet 1
Subnet 2
Registrar
& proxy
IP-based Network
CH
Subnet 1
Subnet 2• When lady in red moves,
she
– leaves her laptop
behind
– Uses another machine
• She can still be located
person@subnet1.org
person@subnet2.org
Registrar
& proxy
person@subnet1.org
person@subnet2.org
Session Mobility
IP-based Network
CH
Subnet 1
MH
Subnet 2
IP-based Network
CH
Subnet 1
Subnet 2
INVITE2
3
1
Service Mobility• Service Mobility allows a roaming user to get the same
view of the network as when he is at home
• At the time of registration
–User’s service profile is retrieved from the home
network
–The service profile is shared with the responsible entity
at home and in the foreign network (wholly or partially)
• The foreign network provides some of the service
required
• The home network still retains responsibility for other
services
• Examples of entries in the profile of interest may be
address book, call handling features, buddy lists, etc.
Key Functions Characteristics
Handoff • May take place between cell, subnet or domain
• Need to optimize the handoff delay and transient data loss ( e.g., end-to-
delay up to 200 ms, 3%-5% packet loss, jitter, for real-time VoIP traffic)
• May use soft-handoff feature of CDMA, but need fast-handoff mechanisms
for other technologies (e.g., 802.11)
• Need to support session based applications for TCP and RTP traffic
Configuration •Should be configured within few milliseconds
•Configures IP address and other server parameters (e.g, DNS, SIP server, Gateway)
Registration • Assist pre-session mobility
• Hierarchical nature will make the registration faster
• Helps location management functionality
Quality of Service
•Need to maintain same QoS during its subnet/domain movement
Location Management
•Allow user to maintain same URI irrespective of point of attachment
Technical issues for mobility management
Motivation for Handover Optimization• Mobility adds complexity to the wireless access
• Cellular-based mobility systems do not suffer from performance degradation
• IP-based systems contribute to performance degradation due to movement across access technologies, domains, and mobility at multiple layers
• Currently there are ad hoc solutions for IP mobility optimization, not engineering practice
– No formal methodology to systematically discover or
evaluate mobility optimizations
– No methodology for systematic evaluation of "run-time"
cost/benefit tradeoffs
Sample IP-based mobility protocols
ForeignSubnet
j.k.l
CH
HomeNetwork
HomeSIP Server
MH
Foreign/visited
network
Outbound
SIP server
2. INVITE
3. MOVED
6. Data
7. Move
1. REGISTER
3a. INVITE
4. OK
5. ACK
ForeignSubnet 2p.q.r
8. RE-INVITE/
RegisterRe-REGISTER
Re-INVITE9. Data
ForeignSubnet
j.k.l
CH
HomeNetwork
HomeSIP Server
MH
Foreign/visited
network
Outbound
SIP server
2. INVITE
3. MOVED
6. Data
7. Move
1. REGISTER
3a. INVITE
4. OK
5. ACK
ForeignSubnet 2p.q.r
8. RE-INVITE/
RegisterRe-REGISTER
Re-INVITE9. Data
ForeignSubnet 1
CH
HomeSubnet
HA
MH
foreign/visited
network
4b. binding update
(MH.IP->MH.COA2)
ForeignSubnet 2
1. REGISTER
2. Data
2a. Tunneled Data
3. Move
4. DATA<CH.IP, MH COA2)
ForeignSubnet 1
CH
HomeSubnet
HA
MH
foreign/visited
network
4b. binding update
(MH.IP->MH.COA2)
ForeignSubnet 2
1. REGISTER
2. Data
2a. Tunneled Data
3. Move
4. DATA<CH.IP, MH COA2)
Mobile IPv4
Application layer mobility (SIP)Proxy MIPv6
Mobile IPv6
ForeignSubnet 1
CH
HomeSubnet
HA
<CH.IP, MH.IP>
<MH.IP, CH.IP>
MH
<HA.IP, M
H.COA.IP<CH.IP
, MH.IP
>>foreign/visited
network1. Registration
ForeignSubnet 2
4. Re-registration
5. New tunneledData
3. Move
2a. Tunneled Data
2. Data
FA
Data
ForeignSubnet 1
CH
HomeSubnet
HA
<CH.IP, MH.IP>
<MH.IP, CH.IP>
MH
<HA.IP, M
H.COA.IP<CH.IP
, MH.IP
>>
<HA.IP, M
H.COA.IP<CH.IP
, MH.IP
>>foreign/visited
network1. Registration
ForeignSubnet 2
4. Re-registration
5. New tunneledData
3. Move
2a. Tunneled Data
2. Data
FA
Data
Data
Signal
CN
HA MN
R1
(PMA1)
R2
(PMA2)
5. PMIP Tunnel 1
11. PMIP Tunnel 2
AAA
Move
2. AAA Request/Reply
1. Access
Initiation
3. Proxy BU
4. AAA Query/Reply
4. Proxy ACK
7. Access
Initiation
6. Home Prefix
advertisement
8. AAA Request/Reply
9. Proxy BU
10. AAA Query/Reply
12. Home Prefix
advertisementHome
Network
Visited 1
Visited 2
CN
HA MN
R1
(PMA1)
R2
(PMA2)
5. PMIP Tunnel 1
11. PMIP Tunnel 2
AAA
Move
2. AAA Request/Reply
1. Access
Initiation
3. Proxy BU
4. AAA Query/Reply
4. Proxy ACK
7. Access
Initiation
6. Home Prefix
advertisement
8. AAA Request/Reply
9. Proxy BU
10. AAA Query/Reply
12. Home Prefix
advertisementHome
Network
Visited 1
Visited 2
Mobility/
Function
Access
Type
Network
Discovery
Resource
Discovery
Triggering
Technique
Detection
Technique
Configuration Key
exchange/
Authentic
ation
Encryption Binding
Update
Media
Rerouting
GSM TDMA BCCH FCCH Channel
Strength
SCH TMSI SRES/A3 DES MSC
Contld.
Anchor
WCDMA CDMA PILOT SYNC
Channel
Channel
Strength
Frequency TMSI SRES/A3
AES Network
Control
Anchor
IS-95 CDMA PILOT SYNC
channel
Channel
Strength
RTC TMSI Diffie-
Hellman
AKA
Kasumi MSC
Contld.
Anchor
MSC
CDMA
1X-
EVDO
EVDO PILOT
Channel
SYNC
Channel
Channel
Strength
RTC TMSI Diffie-
Hellman/
CAVE
AES MSC PDSN/MSC
802.11 CSMA/
CA
Beacon
11R
11R
802.21
SNR at
Mobile
Scanning.
Channel
Number,
SSID
SSID,
Channel
number
Layer 2
authentic
ate
802.1X
EAP
WEP/WP
A
802.11i
Associate IAPP
Cell IP Any Gateway
beacon
Mobile
msmt.
AP
beacon
ID
GW Beacon MAC
Address
AP address
IPSec IPSec Route
Update
Intermediat
ey
Router
MIPv4 Any ICMP
Router
adv.
FA adv.
ICMP
Router
Adv.
FA adv.
L2
triggering
FA adv FA-CoA
Co-CoA
IKE/PA
NA
AAA
IPSec MIP
Registratio
n
FA
RFA
HA
MIPv6 Any Stateless
Proactive
CARD
802.21
11R
Router
Adv.
Router
Prefix
CoA IKE/PA
NA
AAA
IPSEC MIP
update
MIP RO
CH
MAP
HA
SIPM Any Stateless
ICMP
Router
802.21
11R
L3
Router
Adv.
Router
Prefix,
ICMP
CoA
AOR
Re-Register
INVITE
exchange
/AAA
IPSEC/
SRTP/
S/MIME
Re-INVITE B2BUA
CH
RTPtrans
Abstraction of mobility functions
35
HandoverEvent
Network discovery &selection
Networkattachment
Configuration Securityassociation
Bindingupdate
Mediareroute
Channel
discoveryL2
association
Router
solicitation
Domain
Advertisement
Identifier
acquisition
Duplicate
Address
Detection
Address
ResolutionAuthentication
(L2 and L3)
Key
derivation
Identifier
update
Identifier
mapping
Binding
cache
Tunneling
Buffering
Forwarding
Bi-casting/
Multicasting
Server
discovery
Identifier
Verification
Subnet
discover
y
P1 P2 P3 P4 P5P6
P11
P13
P12
P21
P22
P23
P31
P32
P33P41
P42P51
P52
P53
P54
P61 P62
P63
P64
System decomposition of handover process
36
Handoff components of a Mobility Event• Network Discovery
– Discover the new networks around the current network• Resource discovery in the new network
– New frequency, QoS parameters• Network Selection
– Handoff decision to switch access networks
• Detection of new point of attachment– Detection at several layers
• Configuration of network identifier– Obtain new temporary connection Identifier (e.g. new IP address, )
• Authentication and authorization– Authentication of identity
• Security Association– Key derivation process between by the mobile upon every move results in signaling
exchange over the air – Processing delay at the end client
• Binding Update– Associate new network identifier for rerouting of data
• Media redirection– Rerouting of data from CN– Encapsulation/decapsulation– Buffering
Handover: Distributed operation across multiple layers
Time
L2PoA
L3PoA
Discovery Detection Configuration
SecurityAssociation
p11
p12
p21
p31
p32 p42
p41Server(Proxy,/HA)
p22
Binding Update
MediaRerouting
p51p31
p32
p41 p42
p42p63
p62
p13p23
p31
p33
MN
p11 p12 p21 p22p31 p41
p61p32 p42
p13 p23p33
p51
p51
p52
p52
CN
p42p52
p61p54
p53 p54
p61
p61p62
p64p51
Inter-domain Handoff Delay Analysis (example)
Operation
L2 Delay
L 2 Scanning
Association
L2 security
L3 Delay
Address Acquisition
DuplicateAddress Detection
ARPUpdate
Local Authentication
AAAProfile
BindingUpdate
Media RedirectionApplication
LayerDelay
-Reduce the handoff delay
-Reduce the packet Loss
Handoff Latency with associated Protocols (example)
AP1 AP2Next
Access
Router
Router Advertisement
DHCP server
PPP
DHCP/PPP
HA/SIP Server
Binding Update
CN
Media
New Media
Binds to AP1
Layer 2 Association
Dual mode
MN
Stateless Auto-configuration
AAA
DAD/ARP
AAA
Server
Layer 2 Security
VPN
VPN
GW
∆∆∆∆1- L2 Hand-over Latency Delay
∆∆∆∆2 – Delay due to
IP Address Acquisition and
Configuration, authentication, authorization
∆∆∆∆3 – Binding update and
Media Redirection delay
∆∆∆∆1
∆∆∆∆2
∆∆∆∆3
∆∆∆∆
∆∆∆∆ =T4
∆∆∆∆1
∆∆∆∆2
∆∆∆∆3
IGMP/RTCP
Mobility Event Systems Modeling with Distributed State (an example)
MN
L2PoA
L3PoA
CN
MobilityAgent
Discovery (Job1)
Detection (Job 2)
Configuration (Job 3)
Binding Update ( Job 5)
Job1 Job2 Job3 Job4
Time
j11
j12
j13
j13
j21
j22
j23j31
j31
j32
j42
j42
j44
j41
Server
j22
Job5 Job6
J53
J51
J51
J52
J61
J61
J62
Security Association (Job 4)
Media redirection ( Job 6)
j32
j31
j32
j43 j44
j41 j42 j43
j43
j42j31
j33 J53 J62
J63
J52
Case I: Mobility Event Systems Modeling with Distributed State (Security Optimization)
MN
L2PoA
L3PoA
CN
MobilityAgent
Discovery (Job1)
Detection (Job 2)
Configuration (Job 3)
Binding Update ( Job 5)
Job1+part of
Job4 overlapped Job2 Job3 Job4 reduced
Time
j11
j12
j13
j13
j21
j22
j23j31
j31
j32
j42
j42
j44
j41
Server
j22
Job5 Job6
J53
J51
J51
J52
J61
J61
J62
Security Association (Job 4)
Media redirection ( Job 6)
j32
j31
j32
j43 j44
j41j42
j43
j43
j42j31
j33 J53 J62
J63
J52
A layered approach to mobility
N
N-1
N-2
N-3
N-4
N-5
N-6
Mobile Mobile
N
N-1
N-2
N-3
N-4
N-5
N-6
MacroMicro
Mobile
N
N-1
N-2
N-3
N-4
N-5
N-6
N
N-1
N-2
N-3
N-4
N-5
N-6
Mobile
Inter-domain Move
N
N-1
N-2
N-3
N-4
N-5
N-6
Mobile
N
N-1
N-2
N-3
N-4
N-5
N-6
Mobile
Layers on the mobile Not Affected due to mobility
Layers on the mobile Affected due to mobility
Layers on the correspondent host
Micro Mobility
N
N-1
N-2
N-3
N-4
N-5
N-6
CH
N
N-1
N-2N-3
N-4
N-5
N-6
Mobile
t1 t2 t3
t1 = processing time in CH
t3 = processing time in Mobile
t2 = transmission time before movement
t3a = L2 reconfiguration+ processing time
t2a = new transmission time
N
N-1
N-2
N-3
N-4
N-5
N-6
Mobile
CH
Internet
AP1 AP2
Mobile
R
Mobile
N
N-1
N-2
N-3
N-4
N-5
N-6
CH
t1 t2a t3a
Old Data Path
New Data Path
L2 move
Domain 1
Subnet 1
Macro Mobility
N
N-1
N-2
N-3
N-4
N-5
N-6
Mobile
Mobile
N
N-1
N-2
N-3
N-4
N-5
N-6
CH
Internet
AP1 AP2
Mobile
R1
Mobile
R2
AP3 AP3
N
N-1
N-2
N-3
N-4
N-5
N-6
CH
t1 t3t2
N
N-1
N-2
N-3
N-4
N-5
N-6
CH
t1 t2b t3b
t1 = processing time in CH
t3 = processing time in Mobile
t2 = transmission time in static mode
t3b = (L2+L3) reconfiguration+ processing
time on the mobile
t2b = new transmission time
L3 move
Old Data Path
New Data Path
Domain 1
Subnet 1Subnet 2
R – Router
AP – Access Point
Inter-domain Mobility
N
N-1
N-2
N-3
N-4
N-5
N-6
MobileInter-domain Move
Mobile
N
N-1
N-2
N-3
N-4
N-5
N-6
N
N-1
N-2
N-3
N-4
N-5
N-6
CH
N
N-1
N-2
N-3
N-4
N-5
N-6
CH
t1 t2 t3
t1 t2c t3c
CH
Internet
AP1 AP2
Mobile
R1
Mobile
R2
AP3 AP3
Domain 1 Domain 2
t1 = processing time in CH
t3 = processing time in Mobile
t2 = transmission time in static mode
t3c = (L2+L3) reconfiguration+ processing
time on the mobile
t2c = new transmission time
Security
Security
Old Data Path
New Data Path
Inter-domain Move
Handoff Operation Across LayersHandoff
Operations
Layer 2 Layer 3 Application
Layer
Discovery Scanning Router
Advertisement
AAA Domain
Advertisement
Authentication Open Auth
EAPoL
IKE, PANA S/MIME
Security
Association
802.11i
4-way handshake
IPSEC TLS
SRTP
Configuration ESSID
Beacon
DHCP
Stateless
URI
(Universal Resource
Identifier)
Address
Uniqueness
MAC
Address
ARP
DAD
SIP
Registration
Binding update Cache
Update
Update CN,
HA
SIP
Re-INVITE
Media Routing IAPP Encapsulation
Tunneling, Forwarding, Bi-casting
Direct
Routing
Handover Taxonomy
Inter-subnet
Intra-subnet
Intra-tech &
Inter-domain
Intra-tech & Intra-domain
Inter-tech &
Inter-domain
Inter-tech &
Intra-domain
Intra-tech &
Intra-domain
802.11 (provider X) to CDMA (provider X)
802.11 (provider X) to CDMA (provider Y)
802.11b (provider X) to 802.11n (provider X)
802.11b (provider X) to 802.11n (provider Y)
Inter-tech & Intra-domain
802.11 (provider X) to CDMA (provider X)Some scenario could be homogeneous as well,
e.g., intra-tech & intra-domain
Multiple Interface Case (802.11b – CDMA1XRTT) – MIP as mobility protocol
802.11 802.11CDMAHandoff19 s
Single Interface Case (802.11b – 802.11b) – SIP as mobility
802.11 802.11Handoff
4 s
Handoff
17 s802.11 CDMA 802.11
Multiple Interface Case (802.11b – CDMA1XRTT) – SIP as mobility protocol
Effect of handoff delay during non-optimized mobility management (experimental results)
Mobility protocols in IETF working groups• DNA: Detecting Network Attachment
• Mip4: Mobility for IPv4
– deployment issues and an addressing known deficiencies and shortcomings in the protocol that have come up as a result of deployment experience
– AAA, enterprise environments, etc.
• MEXT (Mobility Extension) – recently formed– mip6
• Address issues related to MIPv6 inter-operability testing
• Modularize the MIPv6 specifications (route optimization, etc.)
• Dual stack MIPv6
– nemo: network mobility
• Security, routing issues for network mobility
– MONAMI6 (multi-homed)
– DMM – Distributed Mobility Management
• MOBOPTS: Mobility OPtimization– IRTF Research Group
• Netlmm : Network-based Localized Mobility Management– ProxyMIPv6
• mipshop: Mobility for IP: Performance, Signaling and Handoff Optimization
– Reducing overhead and handoff latency for MIPv6, using HMIPv6 and FMIPv6
• Seamoby (old): context transfer, handoff candidate discovery, and dormant mode host alerting
• 3GPP– VCC, MMSC
• IEEE 802.21• 3GPP2
Network Layer Mobility
Motivations• Internet originally designed for fixed nodes
• Routing
– Host-based is not scalable
– Hierarchical
• Assumes geographical/topological clustering of addresses
• Small routing tables
• Mobility
– When do we want to keep IP address?
– IP address for identity vs. routing
– Need two IP addresses?
IP-based Network
CH
HomeSubnet
MH
ForeignSubnet
Towards an IP Mobility Solution• Mobile Host – MH
–2 IP addresses
• MH.IP: original home address
• MH.COA.IP: foreign network care-of address, for
routing
• Home Agent
–In home network
–Has binding between MH.IP and MH.COA.IP
• Intercepts packets for MH.IP and re-directs them
• Foreign Agent
–In foreign network
–Handles foreign network aspects, e.g. un-encapsulation
• Tunneling concept
Mobile IP Basic Operations
IP-based Network
CH
HomeSubnet
HA
<CH.IP, MH.IP>
<MH.IP, CH.IP>
MH<CH.IP, MH.IP>
FA<MH.IP, CH.IP>
� CH to MH
� CH sends packet to MH home address as usual
� HA in home subnet intercepts packet, tunnels it to FA
� FA un-encapsulates packet, forwards to MH
� MH to CH
� Normal IP routing from foreign network
home
network
foreign/visited
network
Mobile IP Registration – FA mode
IP-based Network
HomeSubnet
HA
MH
FA
1. (optional) agent solicitation
2. Agent advertisement
3. MIP registration request
4. MIP registration request
5. MIP registration reply
6. MIP registration reply
home
network
foreign/visited
network
12
364
5
ForeignSubnet
Mobile IP Basic Operations: with co-located
COA
IP-based Network
CH
HomeSubnet
HA
<CH.IP, MH.IP>
<MH.IP, CH.IP>
MH
� CH to MH
� CH sends packet to MH home address as usual
� HA in home subnet intercepts packet, tunnels it to COA of MH
� MH un-encapsulates packet, processes it
� MH to CH
� Normal IP routing from foreign network
home
network
foreign/visited
network
Foreign Subnet
Mobile IP Registration: with co-located
COA
IP-based Network
HomeSubnet
HA
MH
DHCP server
1. Obtain IP address in foreign/visited network, e.g. using DHCP
2. MIP registration request
3. MIP registration reply
home
network
foreign/visited
network
23
Mobile IP Assessment
•Pros
–Overlay on IP
–Transparent to higher layers
• Applications don’t
need to be changed
–No changes needed in CH
• No awareness of
mobility needed in
legacy hosts
• Cons
– Routing efficiency
• Triangular routing
– Encapsulation overhead
– Update latency
– Single point-of-failure
• What is home agent
goes down?
– Signaling overhead
Mobile IPv6
ForeignSubnet
Mobile IPv6 basics
IP-based Network
CH
HomeSubnet
HA
<MH.IP, CH.IP>
MH
� Address auto-configuration is inherent in IPv6
� No FA, no triangular routing
� Use of source routing through MH.COA.IP, avoids/reduces
encapsulation overhead
� But if any packets go through HA, would still be tunneled to MH
� Binding update can be piggybacked on data packets
home
network
foreign/visited
network
<CH.IP, MH.IP
(through MH.COA.IP)>
binding update (MH.IP->MH.COA.IP)
binding update
Mobile moves between visited subnets4a. binding update
Foreign
Subnet 1
CN
Home
Network
HA
MN
4b. binding update
(MN.IP->MN.CoA2)
Foreign
Subnet 2
1. REGISTER
2. Data
2a. Tunneled Data
3. Move
4. DATA
(CN.IP, MN CoA2)
Foreign/visited
network
4a. binding update
Foreign
Subnet 1
CN
Home
Network
HA
MN
4b. binding update
(MN.IP->MN.CoA2)
Foreign
Subnet 2
1. REGISTER
2. Data
2a. Tunneled Data
3. Move
4. DATA
(CN.IP, MN CoA2)
Foreign/visited
network
ForeignSubnet
Mobile IPv4: Route Optimization
IP-based Network
CH
HomeSubnet
HA
<MH.IP, CH.IP>
MH
� Removes triangular routing
� CH to MH
� In this illustration, we assume co-located COA is used
� CH sends packet to MH.COA.IP directly
� MH to CH
� Normal IP routing from foreign network
home
network
foreign/visited
network
<CH.IP, MH.COA.IP >
binding update (MH.IP->MH.COA.IP)
ProxyMIPv6• ProxyMIPv6 is a Network-based Localized
Mobility Management Protocol with following goals:– Handover Performance Improvement
– Reduction in Handover-Related Signaling Scheme
– Location Privacy
– Limit the overhead in the network
– Simplify Mobile Node Mobility Management
– Link Technology Agnostic
– Support for Unmodified Nodes
– Localized Mobility Management
– Support for IPv4 and IPv6
– Configurable Data Plane Forwarding
ProxyMIPv6
CN
HA MN
R1
(PMA1)
R2
(PMA2)
5. PMIP Tunnel 1
11. PMIP Tunnel 2
AAA
Move
2. AAA Request/Reply
1. Access
Initiation
3. Proxy BU
4. AAA Query/Reply
4. Proxy ACK
7. Access
Initiation
6. Home Prefix
advertisement
8. AAA Request/Reply
9. Proxy BU
10. AAA Query/Reply
12. Home Prefix
advertisementHome
Network
Visited 1
Visited 2
CN
HA MN
R1
(PMA1)
R2
(PMA2)
5. PMIP Tunnel 1
11. PMIP Tunnel 2
AAA
Move
2. AAA Request/Reply
1. Access
Initiation
3. Proxy BU
4. AAA Query/Reply
4. Proxy ACK
7. Access
Initiation
6. Home Prefix
advertisement
8. AAA Request/Reply
9. Proxy BU
10. AAA Query/Reply
12. Home Prefix
advertisementHome
Network
Visited 1
Visited 2
LMA
Proxy MIPv6 Flow – Initial attachment
MN MAGLMA
MN Attachment
(MN-ID)
MN Attached Event
(Acquire MN-Id
and profile)
PBU (Proxy Binding Update)
Accept PBU
(Allocate MN-HNP, Setup BCE and Tunnel)
Proxy Binding Acknowledgement
Accept PBA
(Setup Tunnel and Routing)Bi-Dir Tunnel Setup
IP Address
Configuration
Stateless/
Stateful
Policy
database
AAA with MN-id
MN’s policy
Router Solicitation
Router Advertisement
DHCP Request
DHCP Acknowledgement
CN
DataTunneled Data
Data
Proxy MIPv6 Flow – Handoff
MN LMAn-MAG
MN Detached
PBU
Accept PBU
(Start MinDelayBeforeBCEDelete Timer)PBA
Accept PBA
(Setup Tunnel and Routing)Bi-Dir Tunnel
Router Solicitation
Router Advertisement
MN retains
HoA/HNP
p-MAG
Bi-Dir Tunnel
MN Detached
EventDeReg PBU
MN Attached
MN Attached Event(Acquire MN-Id and profile)
PBU
PBA
CN
Data Data
data
Tunneled data
data
Policy
Database
Proxy MIPv6 in CDMA Network(example)
SIP REGISTER (HoA)
MNPDSN#1
(MAG)
PDSN#2
(MAG)
DHCP
#1LMA
P-CSCF
#1
SIP INVITE
P-CSCF
#2S-CSCF
PPP
DHCP
#2
PCRF
#1
PCRF
#2CN
Router Advertisement (Home Prefix)
DHCP Information Request/Ack (P-CSCF#1)
Proxy Binding Update/Proxy Binding Acknowledgement (Home Prefix)
Media
MN handoff
PPP
Router Advertisement (Home Prefix)
Proxy Binding Update/Binding Acknowledgement (Home Prefix)
SIP REGISTER
DHCP Information Request/Ack (P-CSCF#2)
Gate Open
SIP Re-INVITE
Media
Gate Open
Session Transfer
Handoff
Delay
DSMIPV6 - Dual Stack MIP6
• Mobile nodes will move to networks that might not support IPv6
• Extends MIPv6 capabilities to allow dual stack mobile nodes to request the dual stacked home agent to tunnel IPv4/IPv6 packets addressed to their home addresses
– Both mobile node and Home Agent are IPv4 and IPv6-enabled
– No need to run both MIPv4 and MIPv6 on the client
– MIPv6 is used between mobile and home agent
– Home agent is available using globally unique IPv4 address
• Proposes extension to Binding Updates (RFC 5555)
HA
v6HA_Addrv4HA_Addr
MN v6HoAv4HoA
HA
v6HA_Addrv4HA_Addr
MN v6HoAv4HoA
Proposed New Extension
• DSMIPv6 to support– To address single version home links (e.g., legacy
3GPP)
• IPv4-only Home Network
• IPv6-only Home Network
IPv4-only home network
IPv6 home network is virtualIPv6-only home network
IPv4 home network is virtual
HAv6HA_Addr
MN
v6HoA
v4HA_Addr
v4HoA
HAv4HA_Addr
MN
v4HoA
v6HA_Addr
v6HoA
Global Ipv4/Ipv6
connectivity
HAv6HA_Addr
MN
v6HoA
v4HA_Addr
v4HoA
HAv4HA_Addr
MN
v4HoA
v6HA_Addr
v6HoA
Global Ipv4/Ipv6
connectivity
HAv6HA_Addr
MN
v6HoA
v4HA_Addr
v4HoA
HAv4HA_Addr
MN
v4HoA
v6HA_Addr
v6HoA
Global Ipv4/Ipv6
connectivity
HAv6HA_Addr
MN
v6HoA
v4HA_Addr
v4HoA
HAv4HA_Addr
MN
v4HoA
v6HA_Addr
v6HoA
Global Ipv4/Ipv6
connectivity
Source IETF 71
Network MovementIP11
IP12
Domain 1
IP00
Mobile
Router
Mobile
Network 1
Advertises
MNP1
LANMobile
Router
Mobile
Network 4
LANMobile
Router
Mobile
Network 3
NetworkMovementBetween domains
Domain 2
IP01
Internet
Mobile
Router
Mobile
Network 2
LAN
LAN
Home
Network 1
Home
Network 2Home
Agent 1
Home
Agent 2
Egress
interface
Ingress
interface
Egress
interface
Ingress
interface
Egress
interface
Ingress
interface
Egress
interface
Ingress
interface
Bi-directional
TunnelBi-directional
Tunnel
BCE
BCE:MNP-> MR’s HoA MR’s HoA -> MR’s CoA
Network Mobility
MNP2
Transport Layer Mobility
Solutions
MSOCKS ( Transport Layer Mobility)
• Basic architecture consists of three pieces
– User level MSOCKS proxy running on a proxy machine
– In-Kernel modification on the proxy machine to provide TCP-splice
service
– Shim Msocks library that runs under the application on the mobile
• Built on the top of SOCKS protocol (Firewall Traversal, RFC 1928)
– Addition to support MSOCK’s basic ability to redirect TCP streams to
a mobile’s changing location
– Connection ID to track the logical connection
– MSOCKS Reconnect request
• Mostly suited for local mobility
• Can be integrated with other firewall proxies
• Related work Indirect TCP, Multi-homed TCP, Bullet-proof FTP
MSOCKS Flow DiagramMobile CHProxy
Connect
Addr, Port
Syn
ACK
Auth.
checksSYN
SYN ACK
ACK
Connect ()
Splice
setup
DATA
DATA
DATA
ACKDATA
ACK
Mobile Proxy CH
C DC D
DATA
DATA
DATA, ACK
DATA,ACK
SYN
SYN,Ack
ACK
Reconnect
Conn ID Auth.
checks
Re-splicing
OK
DATA DATA
TCP Migrate Approach• Join together two separate connections
– Unifies context space
– Reference previous connection with token
– Minimal changes in state machine
• Location Update
– Use DYNAMIC DNS
• Seamless connectivity via connection migration
– It notifies current set of correspondent hosts
• Adds a migrate option
– SYN packets of new connection carries it
– It indicates the new connection to be joined with
previous one
• Key negotiation
– Uses Diffie-Hellman Exchange
– Use IPSec or SSH for real security
• Works with NATs/PATs and middle boxes
• Related work
– Extended-TCP (Huitema et al)
– Migratory TCP (Sultan et al)
– Bullet-proof FTP
TCP Connection Migration
SYN
ACK
1
2
3
4
ACK
MN CN
Disconnection
SYN
ACK
5
6
7 ACK
MN – Mobile Node
CN – Correspondent Node
1. Initial SYN
2. SYN/ACK
3. ACK ( with data)
4. Normal Data
5. Migrate SYN
6. Migrate SYN/ACK
7. ACK (with Data)
Initial Key
exchange
After the move
TCP state diagram
LISTEN
SYN_SENTSYN_RECEIVED
ESTABLISHED
CLOSED
MIGRATE_WAIT
appl:passive open
send:(nothing)
recv:SYN
send:SYN,ACK
2MSL timeout
appl:
clo
se o
r ti
meo
ut
Mobile SCTP (Stream Controlled Transport Protocol)
• Mobility Enabled Transport Protocols
– Allows change in IP address when communication is still intact
– Transport layer protocols that allow modification of end-points
– TCP and UDP do not allow that
• Multi-homing feature will allow simultaneous connection to two different networks
– Allows make-before-break, soft-handover
• SCTP supports multi-homing/multistreaming
– SCTP transport addresses can all share the same port number
– SCTP end-point can use multiple IP addresses for an association between two end-points
– Allows the end-points of a single association to have multiple IP addresses
– Allows for independent among data streams
• ADDIP feature makes SCTP a mobility enabled transport protocol
– It allows SCTP end-points to change IP addresses
– Server must use multiple IP addresses and ADDIP implementation
Mobile SCTP• Use Cases
– Assume at least two network interfaces
– Keeping seamless connectivity while switching between different
network technologies
• Wireless LAN in a hotspot and 3G network
– Combination of link layer mobility and transport layer mobility for
smooth handover
– Provides multiple paths to the server adding redundancy
• Mobile servers
– Servers can move also (e.g, ftp server, streaming server)
– Dynamic assignment of IP addresses of the mobile servers
• Dynamic DNS takes care of it
– Mobile SCTP does not handle simultaneous handover of both
SCTP end-points
– It handles only if they happen sequentially
HIP(Host Identity Protocol)
Basics of HIP• Host identity namespace consists of host
identifiers– Identity, identifier
• Host identifier is cryptographic in nature– public key of an asymmetric pair
– Usually stored as • DNS RR similar to IPSECKEY RR
• PKI
• HIP base exchange uses cryptographic HI to set up pair of ESP SAs
• SA is not bound to the IP address
• HIP is middle-box friendly
Host Identity Protocol (HIP)
A
B
Process
SOCKET
End-Point
NODE A
Application T
IP
Address
Locator
Application T
Service
A
B
Process
SOCKET
End-Point
NODE A
IP
AddressLocator
Host
identity
Service
A
B
Process
SOCKET
End-Point
NODE A
IP
AddressLocator
Host
identity
Service
NODE A
A
B
Process
SOCKET
End-Point
IP
AddressLocator
Host
identity
Service
Node A moves
Host identity does not change
but IP address changes
Regular Stack
HIP Stack
Node A moves
HIP Mobility
• HIP decouples the transport from the internetworking layer– Binds the transport associations to Host Identities through HIT or
LSI
– Decoupling makes end-host mobility and multi-homing easier
– TCP and ESP are bound to HITs not IP addresses
• HIP mobility includes IP address change by either party– PPP, DHCP, IPv6 prefix, NAT
– IP addresses are used only for routing
• Since SA is not bound to the IP address– Internal control of SA is done by HITs
– SA is not changed when any mobility protocol is used
• Rendezvous mechanism to locate the end-points– Helps during simultaneous mobility
• Re-establishment of mobile handover will not require HIP negotiation or disruption of transport services
HIP mobility - scenario
TCP (Sockets bound to HITs)
ESP (HIT_s,HIT_d) SPI
HIP {HIT_s, HIT_d, SPI} {IP_s, IP_d, SPI}MH
IP
TCP (Sockets bound to HITs)
ESP (HIT_s,HIT_d) SPI
HIP {HIT_s, HIT_d, SPI} {IP_s, IP_d, SPI}MH
IP
TCP (Sockets bound to HITs)
ESP (HIT_s,HIT_d) SPI
HIP {HIT_s, HIT_d, SPI} {IP_s, IP_d, SPI}MH
IP
Mobile
Host
Peer
Host
UPDATE (ESP_INFO, LOCATOR, SEQ)
UPDATE (ESP_INFO, LOCATOR, ACK, ECHO_REQUEST)
UPDATE (ACK, ECHO_RESPONSE)
Mobile
Host
Peer
Host
UPDATE (ESP_INFO, LOCATOR, SEQ)
UPDATE (ESP_INFO, LOCATOR, ACK, ECHO_REQUEST)
UPDATE (ACK, ECHO_RESPONSE)
IP
Address
changes
Application Layer Mobility
SIP-based Mobility Management
SIP Signaling Components
UAC
UAS
UAS
UAC
SIP server
RegistrarProxy
Location
Database
UDP/5060 (Signaling)
UDP/5060 (Signaling)
SIP UA
CH
SIP UA
MH
Outside
Media
Application
RAT
WB
VIC
CHAT
VNC
RAT
WB
VIC
CHAT
VNC
audio
video
white board
text
desktop sharing
Real-time Application
RTP/UDP
RTCP
P0 P0
P0+1 P0+1
Redirect
Proxy
With permission from Xiaotao Wu
SIP Mobility - Basics
CH
HA
FA
Home Network
MN
Tunnelled data
data
data
CH
SIP
Server
Home Network
MN
1
2
3
4
5
Plain Mobile IP
CH
SIP
Server
Home Network
MN
movesMN
Foreign Network
SIP Personal Mobility
SIP Mid-session mobility
1
2
3
4
1. SIP INVITE
2. 302 client moved
3. SIP INVITE
4. SIP OK
5. Data
1. MN moves
2. MN re-invites
3. SIP OK
4. Data
CH
SIP
Server
Home Network
MN
movesMN
Foreign Network
SIP
ServerCH
When both move
SIP-based Mobility FeaturesPersonal
Mobility� One address to many potential terminals – forking
proxy
� Many addresses reaching one terminalService
Mobility� Allows users to maintain access to their services while moving
� Maintain speed dial list, address books, buddy lists, incoming call handling
(e.g, CPL)Session
Mobility� Allows a user to maintain an on going media session even while changing
terminals– Use of MGCP/Megaco– Third-party Call control– Refer Mechanism
Pre-
session
mobility
� pre-session mobility by means of unique URI
� use of SIP proxy, redirect, registrar
� Hierarchical registration for faster registration updateMid-session
Mobility
(RTP/ UDP)
� Move between cells, subnets, domains, supports fast-handoffs
� SIP Re-invite, RTP SSRC/IP address
� RTP translator for fast hand-off within a domain
� Duration limited multicast between subnet handoff
� use of RTSP to control multi-media stream server
TCP � Mobility Proxy, Mangling (MIP-LR), IDMP(DMA)
SIP Mobility Key Design Features• Mobility as part of application layer signaling
– No need to install Mobile IP stack
– Interaction with DNS, HTTP, LDAP for location management
– personal mobility by means of unique URI
– Re-Invite CH for terminal mobility, via SIP server when CH also moves
• Redundancy/survivability
– Determine multiple SIP servers during auto-configuration
• Via DRCP configuration option, multicast discovery, use of SRV record in DNS
• Retransmission during call setup by switching over to secondary server in case of a failure
• Hierarchical SIP registration
– No need to go back to home registrar, register in the visiting domain - less delay
– Registration gets proxied to other SIP servers - Hierarchical registrars - Optimized
• Performance
– No triangular routing—reduces delay
– No IP-IP tunneling—reduces network load and saves overhead
• When SIP server also moves
– Use Dynamic DNS
SIP-based subnet and domain Mobility handoff results (from experiment)
CH MH
59.521 - 10.1.4.162
00.478RTP2
RTP1
00.652
00.701
RTP2 00.938
RTP1
00.949
00.960
01.031
01.151
(De-REG+REG) (01.049, 01.052)
01.37
00.759 - 10.1.1.130
PANA
OK
ACK
Pr
Pr = 220 ms
RTP1
01.52 – 10.1.1.130
Pr
Time
Sec
Handoff timing with more granularity
Operation DRCP PANA SIP MediaRTP
Subnet
Handoff
79 ms 2 ms 228
ms
1490
ms
Domain
Handoff
81 ms 45 ms 289
ms
1656
ms
Fig 1. Handoff Factors for SIP-based mobility
Table 1. subnet/domain handoff
Experimental values
∆∆∆∆2 ∆∆∆∆3 ∆∆∆∆3 ∆∆∆∆
Handoff
(L2+DRCP+PANA)
CHMH
Old IP address IP1
New IP
address IP2
Re-Invite
X
RTP to IP1
RTP to IP2
OK
ACK
RTP to IP1
Voice
20 msec
time interval
X
Pr
Pr
Pr
Handoff
(L2+DRCP+PANA)
CHMH
Old IP address IP1
New IP
address IP2
Re-Invite
X
RTP to IP1
RTP to IP2
OK
ACK
RTP to IP1
Voice
20 msec
time interval
X
Pr
Pr
Pr
Operational comparison with Mobility
Protocols
Intra-domain
encapsulation
Inter-domain
encapsulation
Changes
to end-systems
Triangle
routing
Infrastructure
change
Fast
handoff
MIP * Yes Yes No Yes No No
MIP-RO Yes Yes Yes No No No
MIP-RR Yes Yes No Yes Yes Yes
MIP-FF Yes Yes Yes Yes Yes Yes
CIP * No No Yes No Yes Yes
HAWAII No No Yes No Yes Yes
MIP-LR * No No Yes No No No
IDMP * Yes Yes No Yes Yes Yes
SIP * No No No No No Yes
MIPv6 * No No Yes No Yes Yes
Protocols
Proxy MIPv6 No No No No Yes Yes
HIP No No Yes No No
Mobility Optimization
Packet Loss, Jitter, Latency
1 2 3 4 5 6
1 3 5
1 2 3 3 4
1 2 3 4
Sender
Receiver(Packet Lost)
Receiver(Jitter)
Receiver(Delay)
Motivation for Optimization• Handoff contributes to
– Change in network connection path between communicating nodes– Discrete Sate Event change at different layers– Rebinding of common set of properties (e.g., association, endpoint address, locator)– Associated delay and packet loss due to these discrete events and rebinding
• Limit jitter, delay and packet loss for real-time applications during different types of handoff
– 150 ms end-to-end delay and 3% packet loss for interactive traffic such as VoIP
– ITU-T G.114
• Essential to reduce handoff delay across layers during re-association and mitigate the effect of handoff delay (i.e., packet loss)– Currently it takes between 4s – 17 s– Packet loss depends upon the CODEC, packet generation rate (G711, G729)
• The challenge is even greater when moving between– Heterogeneous domains – Heterogeneous access technologies (e.g., CDMA, 802.11)– Simultaneous mobility
It is desirable to have a common optimization framework and set of formal methodologies for mobility optimization
Performance Requirement• Limit value of end-to-end delay, jitter and packet loss
• Performance requirement varies based on the traffic class
• ITU-T G.114 recommends 150 ms as the upper limit for most applications
• 3GPP TS23.107 defines 4 application classes– Conversational, Streaming, Interactive, Background
• One way delay tolerance for video conference is 200 - 300 ms
• Several performance parameters determine QoS– Transmission Rating Factor (R factor)– End-to-end (One way mouth-to-ear)– Call Blocking ratio
• Different standards bodies define the performance requirement varies based on the type of traffic
Mobility Event Distributed Tasks (Sample)
Operation
(Job)
Task1 Task2 Task3 Task 4
Discovery (J1) Scanning
J11
Beaconing
J12
Association
J13
Open Auth
J14
Detection
(J2)
Beaconing (L2),
Router
Advertisement (L3)
J21
Solicitation
J22
Link Switch
J23
Configuration
(J3)
Identifier
Acquisition
J31
Duplicate
Address
Detection
J32
Mapping
Identifier
J33
Security Association
(J4)
Key distribution
J41
Authenticatio
n
J42
Encryption
J43
Decryption
J44
Binding
Update
(J5)
Tunneling
J51
Mapping
IP addresses
J52
Caching
J53
Media
Redirection (J6)
Encapsulation
J61
Decapsulatio
n
J62
Buffering
J63
Forwarding
J64
Optimization of Network Discovery and Selection
Layer 2 discovery process (802.11)
State1 UnauthenticatedUnassociated
State 2Authenticated
Unassociated
State 3AuthenticatedAssociated
SuccessfulAuthentication
SuccessfulAuthentication orRe-association
Disassociation
Notification
De-authentication
Notification
De-authenticationNotification
Class 1
Frames
Class 1 & 2
Frames
Class 1, 2 &3
Frames
Class 1 Frames –Control Frames
Class 2 Frames –Management Frames
Class 3 Frames –Data Frames
State1 UnauthenticatedUnassociated
State 2Authenticated
Unassociated
State 3AuthenticatedAssociated
SuccessfulAuthentication
SuccessfulAuthentication orRe-association
Disassociation
Notification
De-authentication
Notification
De-authenticationNotification
Class 1
Frames
Class 1 & 2
Frames
Class 1, 2 &3
Frames
Class 1 Frames –Control Frames
Class 2 Frames –Management Frames
Class 3 Frames –Data Frames
Discovery
Scanning
Authentication Association
Beaconing
MN
L2PoA
MN L2
PoAMN L2
PoA
Discovery
Scanning
Authentication Association
Beaconing
MN
L2PoA
MN L2
PoAMN L2
PoA
Layer 2 Handoff Delay (802.11)
• Discovery Phase
– Active scanning
• MN probes AP
– Passive scanning
• AP sends beacons
periodically
• Authentication Phase
– Open authentication
– Shared authentication
– 802.11i – 4 way handshake
• Association Phase
Station performing handoff All APs within
range on all channels
MN
Probe Request
Probe Response
(broadcast)
New
AP
Reassociation
Request
De-authentication
Authentication
Request
Authentication
Response
Re-association
Request
Re-association
Request
Re-association
Response
Probe
Delay
De
-au
the
ntica
tio
n
De
lay
Authentication
Delay
Re-association
Delay
Chan 1
Chan N
Sample Layer 2 and Layer 3Delay
Under
study
100 ms4-5
s
1 – 2
s
150 ms4-5
s
Time
∆∆∆∆2
Proactive
IP
StaticAuto
IP
FA
COA
DHCP (v6)DHCP
ARP w/o
Method
(Linux)
Under
study
100 ms4-5
s
1 – 2
s
150 ms4-5
s
Time
∆∆∆∆2
Proactive
IP
StaticAuto
IP
FA
COA
DHCP (v6)DHCP
ARP w/o
Method
(Linux)
300- 400
ms
DRCP
160ms
500ms
PPP
7-8s
L3 Delay
SA SF
Under
study
100 ms4-5
s
1 – 2
s
150 ms4-5
s
Time
∆∆∆∆2
Proactive
IP
StaticAuto
IP
FA
COA
DHCP (v6)DHCP
ARP w/o
Method
(Linux)
Under
study
100 ms4-5
s
1 – 2
s
150 ms4-5
s
Time
∆∆∆∆2
Proactive
IP
StaticAuto
IP
FA
COA
DHCP (v6)DHCP
ARP w/o
Method
(Linux)
300- 400
ms
DRCP
160ms
500ms
PPP
7-8s
L3 Delay
SA SF
14 msHostap (Managed)
5 msMADWIFI
250 msOrinoco +Windows
300 msCentrino + Linux (Passive scanning)
400 – 600 msDLink +Linux
100 – 160 msOrinoco+Linux
200 – 300 msAiroNet +Linux
L2 HandoffH/W - OS
14 msHostap (Managed)
5 msMADWIFI
250 msOrinoco +Windows
300 msCentrino + Linux (Passive scanning)
400 – 600 msDLink +Linux
100 – 160 msOrinoco+Linux
200 – 300 msAiroNet +Linux
L2 HandoffH/W - OS
L2 Delay
Layer 2 Discovery Optimization
General techniques:• Reduce the scanning time• Caching of ESSID• Use of second interface• 802.11 specific discovery• Proactive Discovery (no scanning)
Proposed Solutions:• Shin et al introduces selective
scanning and caching strategy• Montavont et al propose periodic
scanning• Velayos et al propose reduction of
beacon interval and performs search in parallel with data transmission
• Brik et al propose to use a second interface to scan while communicating with the first interface
• 802.11u, 802.11k• Forte and Schulzrinne• Application Layer proactive
discovery (e.g., Dutta et al)
Network Detection Mechanisms
• Detection of Layer 2
– SNR drops below a threshold
– Promiscuous Mode to detect other Access Point overlapping
– Proactive Layer 2 handoff
– Beacon Interval
– Client polling interval
• Detection at layer 3
– Enabling L2 handoff event to trigger L3 handoff
• Network Initiated, Mobile Initiated by L2 trigger
– Lazy Cell Switching, Prefix matching, Eager Cell Switching
– ICMP Subnet Router Advertisement
– FA server advertisement
• Application layer detection
– Monitoring an incoming data stream
– Based on GPS co-ordinates of the terminal
• Proposed optimization techniques– Cross layer triggers help detect
the PoA at upper layer
– Passing layer 3 information as part of layer 2 information
– Hybrid scanning to detect the loss of access point
Optimization of Layer 3 Configuration
Components that affect L3 configuration and optimization techniques for layer 3 configuration
• Layer 3 address
acquisition
– Proactive caching
• Duplicate Address
Detection
– Optimistic DAD,
Proactive DAD,
Passive DAD,
– Router Assisted DAD
• NUD (Neighbor
Unreachability Detection)
– Aggressive Router
Selection
Configuration
Identifier
AcquisitionDuplicateAddressVerification
IdentifierMapping
Layer 2
Layer 3
Mobile
NodeServer Network
Mobile
Node L3 POA Network
MNServer
L3
PoA
Configuration
Identifier
AcquisitionDuplicateAddressVerification
IdentifierMapping
Layer 2
Layer 3
Mobile
NodeServer Network
Mobile
Node L3 POA Network
MNServer
L3
PoA
IP Address Discovery Methods• Static
– Works only when a set of possibly visited networks is known in advance
– Each Mobile can be pre-assigned a fixed set of IP addresses for use on these frequently visited networks
• Stateful– DHCP Server, Relay Agent, DRCP
– PPP Server
– MIP Care-of-address (MIP-COA)
• Stateless– IPV6 provides this option
– Combination of link-local prefix and network prefix computes an address of global scope
• Auto-IP– Zero-conf scenario provides 169.154/16 Network address for the local link
– But is not globally routable
• GPS-IP
– Obtains an IP address based on the GPS location, machine ID and MAC address
– Supposed to help the fast-handoff
IP Discovery methods/Timing/ Triggering
FactorsOS DHCP
∆∆∆∆2
DHCP(w/o
ARP)
∆∆∆∆2
DRCP
∆∆∆∆2
(v6)∆∆∆∆2 PPP
∆∆∆∆2
MIP (∆∆∆∆2)FA CoCOA COA
AutoIP∆∆∆∆2
L2 switch (∆∆∆∆1)802.11 CDMA
Static
IP (∆∆∆∆2)
Linux
Windows
Triggering
Method
Triggering
Method
GPS
IP
∆∆∆∆2
7-8
Sec
~4-15
sec
300-
400 msec~ 100
msec
L2
(client)
L2
(client)
L2 (client)
L3 (Server)
L2/
Client
L3/
serverN/A
15 Sec
L2
(client)N/A
L2
/Client
100-150 ms
(Beacon
Interval)
~27 ms
SNR
Threshold
Pilot
Signal
State
less
DH
CP
L3
L3
H. Time/
T. Methods
Handoff
Time
(∆∆∆∆2/∆∆∆∆1)
Handoff
Time (∆∆∆∆2/∆∆∆∆1)
160
msec
TBD
~15sec ~4sec N/A TBD TBD
N/A100-
200 ms
TBD
(~100ms)
L2/L3
L3/
GPS
coordinate
based
L2
(client)
Server
Server
~ 3-5Sec
1-2 sec
Same
as
DHCP’
DRCP/
PPP
Server
N/A
N/A
5sec DHCP 15 sec
Client
Threshold
~27 ms
(Soft
HO)
L3/
server
Server
~500ms
- 1 sec
SNR
Threshold
Pilot
SignalL2/L3
** Some of the numbers shown above are based on experiment in lab environment and may vary based on the processing
power and load in the network
∆∆∆∆1 - L2 Detection
∆∆∆∆2 - IP address Discovery
∆∆∆∆3- Media Redirection
Soft
h/o
Optimizing Layer 3 - in IPv6 - SIPv6 and MIPv6
MNNew
Router
RouterAdvertisement
200 OK
detachment fromold access medium
attachment tonew access medium
handoffdetection
handoff completion(signaling)
Re-INVITE
CN
handoff completion(media)
Delay on Media
UDP packet
ACK
DAD
D1
D2
D3
Signaling (ms) Media (ms)
H123890 3854
H233932
HANDOFFCASE
SIP(DAD)
SIPNDAD
MIPv6NDAD
SIPDAD
SIPNDAD
MIPv6NDAD
171.4 1.5 420.8 21.1
H31
161.6 2.0 4187.7 418.6 30.3
1934.7 161.1 1.0 1949.4 408.4 25.3
Effect of DAD Handoff Delay
Handoff Flow
NUD
Optimizing L3 configuration in IPv4Standard DHCP timing
Message time (Absolute timing) Discover 11.931577
Offer 11.944456
Request 11.994972
ACK 12.099620
ARP Check 12.106605
ARP Reply 27.114676
Total time 15.183099
Without ARP checking
Average Minimum Maximum
436.75 ms 303 ms 535 ms
With Application
Application Average Min Max Ave. rate A Loss.
RAT 1416.46 ms 1363 ms 1524 ms 4515.92 Bps 6396.63
Bytes
vic 1314.23 ms 1273 ms 1368 ms 5298.33 Bps 6963.23 Bytes
Authentication Optimization
How security related protocols affect
performance
• Security protocols have an impact on the performances of the network
– End-to-end latency
– Throughput
– Handoff delay
• Main components that affect the performance
– Authentication/authorization, Key Derivation, Encryption
• Security related delays may affect all the layers
• Layer 2 (e.g., 802.11i, WEP)
• Layer 3 (IPSEC/IKE)
• Upper Layers (e.g., TLS, SRTP)
Security
Association
KeyDistribution Authentication Encryption
Layer 2
Layer 3
Layer 4
ServerMobile Network
MN
MN Server
L3
POA
Security
Association
KeyDistribution Authentication Encryption
Layer 2
Layer 3
Layer 4
ServerMobile Network
MN
MN Server
L3
POA
Authentication Optimization
• Authentication mechanism requires 802.1x message exchange with the authenticator in the target network
• Number of round trip signaling and key derivation process need to be minimized
• Low latency re-authentication
• Authentication can be done proactively
• Context can be transferred
• Layer 3 authentication bootstraps layer 2 authentication process
Optimizing authentication Related Work
• IEEE Standards– IEEE 802.11i provides pre-authentication at link-layer in the
distribution system (DS)– IEEE 802.11r improves 11i by introducing a new key hierarchy but it
does not work between DSs either.
• Context transfer solutions (Bargh et al, Georgiades et al, Duong et al)– Security problems such as “domino effect”– Assume certain trust relationships which might not be possible in
certain scenarios.– Oriented towards the same technology
• Re-authentication
• Pre-installation based on movement pattern (Mishra et al, Pack et al )– AAA assisted key installation– Works within the same administrative domain
• MIPv6 and AAA assisted (Ruckforth et al)– Limited to MIPv6 and within the same domain
• Cooperative Roaming (Forte et al)– Works within a domain
802.11i – Pre-authentication Flow
1x controlled port enabled & IP traffic
EAPOL Start
EAPOL-Request(EAP-Req/ident)
EAPOL-Response(EAP-Resp/ident)
IEEE 11i
Pre-Authentication
STA Current AP Target AP
EAPOL-Request(EAP-TLS/Start)
EAPOL-Response(EAP-TLS/Client-Hello)
EAPOL-Request(EAP-TLS/ServCert)
EAPOL-Response(EAP-TLS/ClientCert)
EAPOL-Request(EAP-TLS/ChangeSpec)
EAPOL-Response(EAP-TLS/Ack)
EAPOL-Request(EAP-TLS/Sucess)
EAPOL Key: Message 1
EAPOL Key: Message 2
EAPOL Key: Message 3
EAPOL Key: Message 4
Associated
(Re)Association
PMKsta-targetAP
4-way hanshake
AAAHAAAv
AAA prot-ans (EAP-TLS/Start)
AAA prot-req (EAP-Resp/Ident)
AAA prot-ans (EAP-TLS/ServCert)
AAA prot-req (EAP-TLS/Client-Hello)
AAA prot-req (EAP-TLS/ClientCert)
AAA prot-ans (EAP-TLS/ChangeSpec)
AAA prot-ans (EAP-Success)
AAA prot-req (EAP-TLS/Ack)
RoamingNon-roaming
PMKsta-targetAP
1x controlled port enabled & IP traffic
EAPOL Start
EAPOL-Request(EAP-Req/ident)
EAPOL-Response(EAP-Resp/ident)
IEEE 11i
Pre-Authentication
STA Current AP Target AP
EAPOL-Request(EAP-TLS/Start)
EAPOL-Response(EAP-TLS/Client-Hello)
EAPOL-Request(EAP-TLS/ServCert)
EAPOL-Response(EAP-TLS/ClientCert)
EAPOL-Request(EAP-TLS/ChangeSpec)
EAPOL-Response(EAP-TLS/Ack)
EAPOL-Request(EAP-TLS/Sucess)
EAPOL Key: Message 1
EAPOL Key: Message 2
EAPOL Key: Message 3
EAPOL Key: Message 4
Associated
(Re)Association
PMKsta-targetAP
4-way hanshake
AAAHAAAv
AAA prot-ans (EAP-TLS/Start)
AAA prot-req (EAP-Resp/Ident)
AAA prot-ans (EAP-TLS/ServCert)
AAA prot-req (EAP-TLS/Client-Hello)
AAA prot-req (EAP-TLS/ClientCert)
AAA prot-ans (EAP-TLS/ChangeSpec)
AAA prot-ans (EAP-Success)
AAA prot-req (EAP-TLS/Ack)
RoamingNon-roaming
PMKsta-targetAP
Network-Layer Assisted
Pre-Authentication Technique
• Assists link-layer optimization mechanism
to work accross subnets and domains
• It is independent of link-layer technology
(e.g., 802.11, CDMA)
• It does not suffer from context transfer
security problems and only assumes basic
trust relationship
• It supports handover across inter-
technology, inter-subnet and inter-domain.
Experimental Testbed
Home AAA
Domain
IEEE 802.11i
Pre-authentication
nAR/PAA
AAAv
AAAh
pAR165.254.55.116/24
165.254.55.115/24
155.54.204.82
10.1.30.1/24
10.1.30.3/2410.1.30.2/24
10.1.10.2/24
10.1.10.1/2410.1.20.2/2410.1.20.1/24
MN
PSK PSK
AP0AP1AP2
Radius/Diameter
PANA pre-auth
Association
&
4-way handshake
Network A Network B
PANA Pre-authentication
Roaming AAA
Domain*
* Roaming AAA Domain in roaming case.
For non-roaming case, it acts as MN’s home AAA
domain.
Non-Roaming: user@isp.netRoaming: user@umu.es
Network Pre-authentication Flows
PANA-Client-Initiation(PCI)
PANA-Start-Request (PSR) [EAP Req/Ident]
PANA-Start-Answer(PSA) [EAP Resp/Ident]
PANA-Auth-Request (PAR) [EAP-TLS/Start]
PANA-Auth-Answer (PAN) [EAP-TLS/Client-Hello]
PANA-Binding-Request[AUTH] (PBR) (EAP-Success)
PANA-Binding-Answer (PBA)
PaC target PAAtarget APx AAAH
SNMPv3-Set(PSK, PaC’s MAC address)
AAA prot-ans (EAP-TLS/Start)
SNMPv3-Ack
PaC’s
Movement
EAPOL Key: Message 1
EAPOL Key: Message 2
EAPOL Key: Message 3
EAPOL Key: Message 4
PSKx PSKx
AAA prot-req (EAP-Resp/Ident)
Network-Layer
Pre-authentication
EAP skipped
1x controlled port enabled & IP traffic
Pre-configuration
PSK
installation
AAAv
AAA prot-ans (EAP-TLS/ServCert)
AAA prot-req (EAP-TLS/Client-Hello)
PANA-Auth-Answer (PAN) [EAP-TLS/ClientCert]
PANA-Auth-Request (PAR) [EAP-TLS/ServCert]
AAA prot-req (EAP-TLS/ClientCert)
AAA prot-ans (EAP-TLS/ChangeSpec)
PANA-Auth-Answer (PAN) [EAP-TLS/Ack]
PANA-Auth-Request (PAR) [EAP-TLS/ChangeSpec]
AAA prot-req (EAP-TLS/Ack)
AAA prot-ans (EAP-Success)
(Re)Association
Associated
current APx
Non-roaming Roaming
4-way hanshake
PANA-Client-Initiation(PCI)
PANA-Start-Request (PSR) [EAP Req/Ident]
PANA-Start-Answer(PSA) [EAP Resp/Ident]
PANA-Auth-Request (PAR) [EAP-TLS/Start]
PANA-Auth-Answer (PAN) [EAP-TLS/Client-Hello]
PANA-Binding-Request[AUTH] (PBR) (EAP-Success)
PANA-Binding-Answer (PBA)
PaC target PAAtarget APx AAAH
SNMPv3-Set(PSK, PaC’s MAC address)
AAA prot-ans (EAP-TLS/Start)
SNMPv3-Ack
PaC’s
Movement
EAPOL Key: Message 1
EAPOL Key: Message 2
EAPOL Key: Message 3
EAPOL Key: Message 4
PSKx PSKx
AAA prot-req (EAP-Resp/Ident)
Network-Layer
Pre-authentication
EAP skippedEAP skipped
1x controlled port enabled & IP traffic
Pre-configuration
PSK
installation
AAAv
AAA prot-ans (EAP-TLS/ServCert)
AAA prot-req (EAP-TLS/Client-Hello)
PANA-Auth-Answer (PAN) [EAP-TLS/ClientCert]
PANA-Auth-Request (PAR) [EAP-TLS/ServCert]
AAA prot-req (EAP-TLS/ClientCert)
AAA prot-ans (EAP-TLS/ChangeSpec)
PANA-Auth-Answer (PAN) [EAP-TLS/Ack]
PANA-Auth-Request (PAR) [EAP-TLS/ChangeSpec]
AAA prot-req (EAP-TLS/Ack)
AAA prot-ans (EAP-Success)
(Re)Association
Associated
current APx
Non-roaming Roaming
4-way hanshake
Key Derivation Process
AAA
PAA
MN
AAA
MSK
AP
MSK
MSK�
PaC-EP-Master-Key �
PSK
MNMSK�
PaC-EP-Master-Key �
PSK�PMK
4-way handshake (PTKs) 4-way handshake (PTKs)
PSKap
PSKap�PMK
MSK� PMK
MSK� PMK
AP
802.11i
Pre-auth
Network-Layer Preauth
AAA
MN
AP
MSK
4-way handshake (PTKs)
MSK� PMK
MSK� PMK
AP
Post-auth
AP
AuthenticationServer
Authenticator
WPA SupplicantWPA Supplicant
Authenticator
AuthenticationServer
Results (II)
Security Association Optimization
Key principles for SA optimization
• Avoid the key exchange by maintaining the end-point address identifier
• Avoid tear down and re-establishment of Security Association
• Reduce the number of signaling messages that help rekeying
• Anchor-based security association
• Clients behind NAT are shielded from IP address change
Description of the Solution (1)
Dynamic Tunnel Management at MN
DMZ
Internal (protected) External (unprotected)
CN
Internal Home
Network
VPN tunnel x-MIP tunnel
VPN
GW x-HA
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
MN
i-MIP tunnel
Internal Visited
Network
i-HA
MNMN MN
ExternalNetwork 1
ExternalNetwork N
Mobike-based solution
Re-Invite
DMZ
Internal (protected) External (unprotected)
CN
Internal Home
Network
VPN tunnel
VPN
GW
MN
Internal
VisitedNetwork
Home
Proxy
MNMN MN
ExternalNetwork 1
ExternalNetwork N
COA1TIA (Tunnel address)
COA2
MOBIKE(modifies SA)
Re-register (IP1)1 2
(IP0) (IP1)
Register (TIA)Register (TIA)
Re-Invite(TIA)
Re-Invite
DMZ
Internal (protected) External (unprotected)
CN
Internal Home
Network
VPN tunnel
VPN
GW
MN
Internal
VisitedNetwork
Home
Proxy
MNMN MN
ExternalNetwork 1
ExternalNetwork N
COA1TIA (Tunnel address)
COA2
MOBIKE(modifies SA)
Re-register (IP1)1 2
(IP0) (IP1)
Register (TIA)Register (TIA)
Re-Invite(TIA)
Results: Mobile IP-VPN
N o n -M a k e -b e fo re -b re a k
3 15 0 0
3 20 0 0
3 25 0 0
3 30 0 0
3 35 0 0
3 40 0 0
3 45 0 0
3 50 0 0
0 5 0 1 00 1 5 0 20 0 2 5 0 3 00
T im e in S e c o n d s
RT
P S
eq
ue
nc
e
R TP S e q ue n c e
8 0 2 .1 1(e n te rp r ise )
C e l lu la r
80 2 .1 1(e n te rp r is e )
P ac k e t L o s sD u e to N o n -m a k e -b e fo r e - b r e ak
N o n -m a k e -b e fo re -b r ea k
N o n -M a k e -b e fo re -b re a k
3 15 0 0
3 20 0 0
3 25 0 0
3 30 0 0
3 35 0 0
3 40 0 0
3 45 0 0
3 50 0 0
0 5 0 1 00 1 5 0 20 0 2 5 0 3 00
T im e in S e c o n d s
RT
P S
eq
ue
nc
e
R TP S e q ue n c e
8 0 2 .1 1(e n te rp r ise )
C e l lu la r
80 2 .1 1(e n te rp r is e )
P ac k e t L o s sD u e to N o n -m a k e -b e fo r e - b r e ak
N o n -m a k e -b e fo re -b r ea k
80 2.1 1-C ellu lar S e cured H an doff
1800
1900
2000
2100
2200
2300
2400
2500
2600
0 20 40 60 80 100 120 140 160 1 80
Time in Se co nd s
RT
P P
ac
ke
t
Se
qu
en
ce
RTP sequence during
handoff
O ut-of-order-packet802.11(en te rprise)
Ce llular 802.11(enterprise)
80 2.1 1-C ellu lar S e cured H an doff
1800
1900
2000
2100
2200
2300
2400
2500
2600
0 20 40 60 80 100 120 140 160 1 80
Time in Se co nd s
RT
P P
ac
ke
t
Se
qu
en
ce
RTP sequence during
handoff
O ut-of-order-packet802.11(en te rprise)
Ce llular 802.11(enterprise)
MNVPN GW
Visite d Network 2(802.11)
V isited Network 1(Cellular)
CN
Tunne l (RTP)
MOBIKE
MOBIKE
13.377
13.342 ( 802.11 is up)
13.554 (First packet o n 802.11)
47.881
51.519
MOBIKE
51.977
PacketLoss
(No-Break-b efore-make)
RTP
Visited Netwo rk 1
(Cellu lar)
13.667 (Last packet on cellular)
MOBIKE
43.103 (Last packet on 802.11)
VP N traffic in 802.11
VP N traffic in cellular
Mobike in cellular
Mobike in 802.11
IP0 is primary address
IP1 is primary address
IP0 is primary address
IP0 – address of 802.11 interface
IP1 – address of cellular interface
MNVPN GW
Visite d Network 2(802.11)
V isited Network 1(Cellular)
CN
Tunne l (RTP)
MOBIKE
MOBIKE
13.377
13.342 ( 802.11 is up)
13.554 (First packet o n 802.11)
47.881
51.519
MOBIKE
51.977
PacketLoss
(No-Break-b efore-make)
RTP
Visited Netwo rk 1
(Cellu lar)
13.667 (Last packet on cellular)
MOBIKE
43.103 (Last packet on 802.11)
VP N traffic in 802.11
VP N traffic in cellular
Mobike in cellular
Mobike in 802.11
IP0 is primary address
IP1 is primary address
IP0 is primary address
IP0 – address of 802.11 interface
IP1 – address of cellular interface
Hand-off with no-make-before break(internal-external-internal) with make-before-break
H o m e -C e l lu la r -H o t s p o t h a n d o ff
5 0 0
1 5 0 0
2 5 0 0
3 5 0 0
4 5 0 0
5 5 0 0
0 1 0 0 2 0 0 3 0 0 4 0 0
T i m e i n S e c o n d s
RT
P S
eq
ue
nc
e
R T P S e q u e n c e
Home802.11
CellularExternal
Hotspot802.11
H o m e -C e l lu la r -H o t s p o t h a n d o ff
5 0 0
1 5 0 0
2 5 0 0
3 5 0 0
4 5 0 0
5 5 0 0
0 1 0 0 2 0 0 3 0 0 4 0 0
T i m e i n S e c o n d s
RT
P S
eq
ue
nc
e
R T P S e q u e n c e
Home802.11
CellularExternal
Hotspot802.11
Home-external-external handoff Mobike-based handoff (cellular-hotspot-cellular)
Optimizing Route between CH and MH
What is RO Optimization?• What is it?
– Ability to maintain direct route between the communicating hosts
– Avoid triangular route for the media traveral
– Most of the mobility protocols in their current form are not route optimized
• Key Principle
– Maintain direct path between the end points for signaling and media
• Proposed Solutions
– Application Layer Mobility
– MIPv6 inherently supports route optimization
– CGA-based route optimization
– Route Optimization in ProxyMIPv6
– Interceptor-assisted packet modifier
– Midcom-proxy assisted route optimization
Trombone Routing (MIPv4, PMIPv4)
Home Network
a) SIP REGISTER
P-CSCF FA/PMA
HAS-CSCF
Home Network
P-CSCF
HAS-CSCF
b) SIP INVITE
MN MN
CN
I-CSCF
Visited Network Visited Network
Core NetworkCore Network
FA/PMA
Trombone Routing (MIPv6, PMIPv6)
Home Network
a) SIP REGISTER
P-CSCFAccess Router/
MAG
HA/LMAS-CSCF
Home Network
S-CSCF
b) SIP INVITE
MN MN
CN
I-CSCF
Visited Network
Core NetworkCore Network
P-CSCFAccess Router/
MAG
Visited Network
HA/LMA
Trombone routing mitigation
P-CSCFS-CSCF
AS
HSS
I-CSCF
PDSN
HA
AP01
802.11b
Home NetworkVisited Network 1
DHCP
cdma2000
RAN Emulator
Mobile Node
192.168.20.0/24
Router
192.168.6.0/24
20.4 20.3 20.2
6.26.1
20.1
10.1
30.1
30.230.330.420.22
192.168.30.0/24
Delay Controller
CN
192.168.30.33
P-CSCF
AP02
802.11b
Visited Network 2
DHCP
192.168.10.0/24
10.4 10.3 10.2
8.28.1
192.168.8.0/24
cdma2000
RAN Emulator
Delay Controller
Optimized SIP Signaling between MN and P-CSCF
Non Optimized SIP Signaling between MN and P-CSCF
• Trombone routing mitigation for SIP signaling
– Non-Optimized
– Selective Reverse Tunneling
Effect of distance on signaling
Types
Of Handoff
Proactive Handoff
(Linearized Values)
Reactive Handoff
(Linearized Values)
Non-optimized Handoff
(Linearized Values)
Emulated
Delay
beween
Home and
Visited
(ms)
SIP, AKA,
Context
Transfer
Delay
(ms)
MIP
Update
Delay
(ms)
L2
PPP
Delay
(ms)
SIP,
AKA,
Context
Transfer
Delay
(ms)
MIP
Update
Delay
(ms)
L2
PPP
Delay
(ms)
SIP,
AKA,
Context
Transfer
Delay
(ms)
MIP
Update
Delay
(ms)
L2
PPP
Delay
(ms)
0 0 51 2736 1.010 62 1523 3,999 41 2,239
50 0 152 2693 1,375 161 1744 4,584 145 2,217
100 0 252 2650 1,741 261 1964 5,170 248 2,194
150 0 352 2607 2,107 360 2184 5,756 352 2,172
200 0 453 2563 2,472 459 2405 6,342 455 2,150
250 0 553 2520 2,838 558 2625 6,927 559 2,128
300 0 654 2477 3,203 658 2845 7,513 663 2,106
350 0 755 2434 3,569 757 3066 8,099 766 2,084
400 0 855 2391 3,935 856 3286 8,685 870 2,061
450 0 956 2347 4,300 955 3506 9,270 973 2,039
500 0 1,057 2304 4,666 1,055 3726 9,856 1077 2,017
Trombone routing mitigation results
0 .0 0 1 .0 0 2 .0 0 3 .0 0 4 .0 0 5 .0 0 6 .0 0 7 .0 0 8 .0 0 9 .0 0 1 0 .0 0
M itig a tio n
N o M itig a tio n
H a n d o ff T im e [m s e c ]
P P P D is c o n n e c tio n L 2 H a n d o ff P P P C o n n e c tio n M IP U p d a te
D H C P fo r n e w P - C S C F S IP R e g is tra tio n S IP R e - IN V IT E
Figure 2: Effect of Trombone routing mitigation
Components Optimized
Components Optimized
(A) PMIP route optimization(Intra-LMA)
HA/LMA
MAG1 MAG2
MN1 MN2
MAG3
MN2
Network Configuration
Non-optimizedDate path
OptimizedPath (MN1 – MN2)
OptimizedPath (MN1-MN2)After handoff
(E) PMIP route optimization(Multiple LMA/HA)
HA1/LMA1
MAG1 MAG2
MN1
MAG3
Network Configuration
HA2/LMA2
MAG4 MAG5
MN2 MN2
MAG6
CORENetwork
Route
Optimized path
after
Hand over
Route
Optimized
path
Non-OptimizedPath
PMIP Domain1PMIP Domain 2
Optimizing a) Binding Updateb) Media Rerouting
Optimizing Binding Update
• Techniques– Reduce the latency due to
longer binding update when the communicating host is far away
– Limit the binding update within a domain
• Proposed Solutions– IDMP– Regional registration-based
Mobile IP– HMIPv6– Anchor-based Application
Layer• B2BUA
– Proactive Binding Update
Binding
Update
Tunneling Mapping Caching
Mobile Network Anchor Mobile CN
Anchor
PointCN
Binding
Update
Tunneling Mapping Caching
Mobile Network AnchorMobile Network Anchor Mobile CN
Anchor
PointCN
“Low Latency Handoffs” Approach Malki et al
• Original MIP makes no assumptions on L2, therefore
– MIP registration can only start after L2 handoff has completed
– MH is not able to communicate before registration process completes
• Cross-layer cooperation, L2 and L3
• Pre-Registration handoff technique
– Proxy route advertisement (and possibly proxy route solicitation) through old FA triggered by “L2 trigger” in old FA (or in MH, for solicitation)
– With some exceptions, MH starts registration through old FA
– Registration may be global or regional
• Post-Registration handoff technique
– Use of Bidirectional Edge Tunnels (BET) between old and new FAs
• Set up after “L2 trigger” in old FA or new FA
• Forwarding begins based on reception of another “L2 trigger” at old FA
– Old FA acts as “anchor FA”, while MH registers with new FA
– Use of BET ends after MIP registration is complete
• Combination
– Use both for maximum protection!
– If pre-registration doesn’t complete in time, use the BET
ForeignSubnet old
Mobile IPv4: Media redirection
ForeignSubnet new
IP-basedNetworkCH
HomeSubnet
HA
MH
� CH to MH
� In this illustration, we assume co-located COA is used
� Forwarding of packets from old FA
� “mid-flight”, or from any CH that does not receive/process binding update
� reduces lost packets due to handoff
home
network
foreign/visited
network
FA, new
FA, old
<CH.IP, MH.IP>binding update
PFANE
IPv4 Proactive Handoff (Malki et al)
oFA nFA
Internet
Mobile
•Allows MN to communicate with
nFA while under oFA
• Provide for data delivery at nFA even
before registration is complete
• Server Initiated/Mobile Initiated
Domain
HA/GFA
Rt. Adv (2)
Rt. Sol (1)
Proxy
Rt. Sol
Proxy
Rt. adv
34
5
Reg
Req
6.
Reg. Req
CH
IPv6 pro-active handoff (FMIPV6)
• Handover Initiation•Mobile initiated
•Server initiated
• Tunnel establishment
• ForwardingPAR
NAR
Internet
Mobile Mobile
Bi-directional Tunnel
CH
PAR: Previous Access
Router
NAR: New Access
Router
1 RtSolPr2 PrRtAdv
3 F-BU
4. HI (Pcoa, Ncoa)
5. HACK
BR
Tunneled data
FMIPv6 Flow (Predictive)
MN
PAR NAR
RtSolPr
PrRtAdv
FBUHI
HAck
FBackFBack
Forward packets
disconnect
Connect
UNA
Packets buffered
Deliver packetsPackets flushed
FMIPv6 Flow (Reactive)
MN
PAR NAR
RtSolPr
PrRtAdv
FBU
HI/Hack if necessary
disconnect
Connect
Deliver packets
In-flight packets forwarded
UNA
FBU
Forward packets including FBAck
Non-optimized (MIPv6)Handoff (no 802.11i)
MIPv6 Non-optimized Handoff
1320
1340
1360
1380
1400
1420
1440
1460
27 29 31 33 35 37 39
Packet arrival time in seconds
Packet
Seq
uen
ce n
um
ber
Series1Handoff delay
Average packet loss = 70 pkts
Reactive FMIPv6 Handoff (Reactive)
FMIPV6 Reactive Handoff
540
560
580
600
620
640
42 43 44 45 46 47 48 49 50
Packet arrival time in seconds
Packet
seq
uen
ce n
um
bers
Series1
HandoffDelay
Average packet loss = 16 pkts
FMIPV6 predictive handover
FMIPv6 Predictive Handover
795
800
805
810
815
820
825
830
835
15 16 17 18 19
Packet Time arrival in seconds
Packet
Seq
uen
ce
Series1
Handoff Delay
Buffered packetsAt NAR
No packet loss
MH2
(2nd)
MH1
(1st)
MH2
(1st)
Domain 2a Domain 2b
SIP
Server 2
SIP
Server 1MH1
(2nd)
Home
Domain 1
Home
Domain 2Domain 1a Domain 1b
Both hosts cannot find the other!
(Figure 7.2)
Communication session
(in normal state):
Exchanging IP packets
Simultaneous mobility in SIP
Home
Domain A
Home
Domain B
A
(2nd)
Domain B1 Domain B2
Home
Agent A
A
(1st )
Domain A2 Domain A1
Home
Agent B
B
(1st )
B
(2nd)
CTIHTI
Communication session
(in normal state):
Exchanging IP packets
A’s binding update is lost as are B’s CTI and HTI
(Figure 7.3)
HTCT
CTIHTI
Simultaneous mobility for MIPv6
Node 1Forwarding
Proxy Node 2
Node 1Redirecting
Proxy Node 2
Node 1Intercepting forwarding
proxy
Node 2
Node 1InterceptingRedirecting
proxy
Node 2
Figure 7.6
Abstract functions of the location proxies
0
0.2
0.4
0.6
0.8
1
1.2
0 50 100 150 200 250 300
Probability
of
failure
Inter-handoff time in seconds
Simultaneous mobility probability
Probability of failure vs. inter-handoff time
(One way latency = 50 ms)
0
0.2
0.4
0.6
0.8
1
1.2
0 50 100 150 200 250 300
Probabilityof
failure
One-way latency (ms)
Failure probability (N = 3)
Probability of failure (PN) vs. one-way-packet delay
Media redirection and optimized
binding update for SIP-based mobility
• Capture the transient packets in-flight and redirects to the mobile– SIP Registrar and NAT-like functionality
• RTPtrans (RTP translator an application layer Translator)
• Mobility Proxy (Linux iptables)
– Outbound SIP proxy server
• Local SIP proxy captures outbound packets
• Limit the signaling due to Intra-domain Mobility– B2B SIP UA
• Emulates Third Party Call control
– Multicast Agent
– Small group multicast
– Duration limited locally scoped Multicast
SIP-based Fast-Handoff
MN
Internet
Visited Domain
MN
MN
Public SIP Proxy
Public SIP Proxy
Public SIP Proxy
IP0
IP1
IP2
Visited
Proxy
Home SIP
Proxy
RTP
Media
(Existing SIP
Session)
OKACK
CNHome
Domain
Subnet
S0
Subnet
S1
Subnet
S2
RTP
Media after
Re-Invite
Register
1
2
3
4
5
Translator
Translator
Translator
Optimized media redirection SIP fast-handoff mechanism -RTPtrans
R
SIPServer/Registrar
RT1RT2RT3
MHMHMH
IP1IP2IP3
CH
IPR1IPR2IPR3
Mapping Database
Register
1
IP1:p1IP2:p1
2’
DelaySimulator
IP2 -> IPR1IP3 -> IPR2...
3
Intra- Domain SIP based fast-handoff(RTP-Trans/NAT based approach)
Domain -D1
4
RT1,RT2,RT3 - RTP Translators
4’
2a Re-Invite
MH CHVisited SIP
Registrar
Media
RT1 RT2 RT3
IP1
IP2
(New Address)
Re-INVITE (2)
REGISTER 2’
Forward
traffic
(IP1:p1 ---> IP2:p1)
New traffic
IP3
(New Address)
Re-INVITE
Re-REGISTER
Forward
traffic(IP2:p1 ---> IP3:p1)
Transient
Traffic during the move
(1)
SIP-CGI (3)
Transient
Traffic during
the move
First move
Second move
IP2
Delay
Box
SIP fast-handoff media redirection Protocol
flowServer
Localized-Binding
Update
ForeignSubnet
ForeignSubnet
Hierarchical Mobile IP
IP-based Network
CH
HomeSubnet
HA
<CH.IP, MH.IP>
<MH.IP, CH.IP>
MH
RFA
� CH to MH
� CH sends packet to MH home address as usual
� HA in home subnet intercepts packet, tunnels it to GFA
� GFA un-encapsulates packet, tunnels it to RFA
� RFA un-encapsulates packet, sends to MH
home
network
GFA coverage area
GFA
RFA
IDMP Fundamentals • Every MN is assigned 2 CoAs
– Global CoA (GCoA)- is globally reachable and remains unchanged as long as the MN moves within a domain.
– Local CoA (LCoA)- has only domain-wide scope and changes with every change in point of attachment.
• Mobility Agent acts as a domain-wide point of packet redirection.
– Packets from outside (addressed to the GCoA) arrive at the MA.
– MA intercepts such packets and tunnels them to the MN's current LCoA.
• During movement inside the domain, the MN only sends a intra-domain BindingUpdate to the MA.
– No need for global signaling (to HA or other servers) unless the GCoA changes.
– Hierarchy reduces the latency of most updates, and significantly lowers the global signaling traffic load.
Hierarchical Mobility Management
IDMP+MIPHome Network
1
2
1
3
2
MA
SA
MN
• All packets from the global Internet tunneled (re-directed) to the
GCoA and are intercepted by the MA.
• MA tunnels each packet to the MN’s current LCoA.
CN
SASA
HADomain
Hierarchical Mobility Management
(IDMP+SIPMM)
MA
MA
HA
CHINTERNET
Intra-Domain
Inter-DomainIntra-Domain
MNMN
LCOA
SIP RE-INVITE (GCOA)
SIP Registrar SIP Registrar
Initial Domain-Based Registration Procedure
Subsequent Intra-Domain Registration
Anchor-based localized binding update SIP-based mobility
RouterCH
Delay
Simulator
SIP
UAC
SIP MA (B2B)
MHMHMH
MoveIP1(Initial position before move)IP2
IP3
IPch
SIP
UAS
SIP
UAS
SIP
UAC
Packets gain for SIP optimized handoff
0
10
20
30
40
50
60
0 20 40 60 80 100 120 140 160
Distance between CH and MH
(Hops)
Nu
mb
er
of
pa
ck
ets
Packets gain for SIP
optimized handoff
Optimizing Binding – SIP Fast-handoff (Results)
HMIPv6 OverviewHomeHomeAgentAgent
Internet
CN
MAP1
RCoA1
AR1 AR2
Movement
LCoA1:RCoA1 LCoA2:RCoA1
Home Networkis far away
MAP2
RCoA2
AR3 AR4
LCoA2:RCoA2 LCoA3:RCoA2
HMIPv6 Protocol Operation
• Mobile has two addresses
– RCoA, LCoA
– RCoA � stateless auto-configuration interfaceid+subnet prefix in MAP option
• Needs update on the implementation only
• HA and CN are unchanged
• MAP performs the function of “local” HA
that binds mobile node’s RCoA to LCoA
Protocol Flow for HMIPv6
MN CNR1 R2MAP1 HA
RA w MAP
option
LCoA and RCoAConfiguration
Local Binding Update (LBU)
MAPPerformsDAD
Local Binding Acknowledgement (LBacK)
BU
BU
MN-MAP Tunnel
RA w MAP option
MobileHands over
Local Binding Update (LBU)
Local Binding Acknowledgement (LBacK)
Tunnel
Data
DataTunneled Data
Cellular IPHomeHomeAgentAgent
Correspondent
HostInternet
(with Mobile IP)
Gateway AGateway A
Cellular IP
Node
Cellular IP
Node
CIP
Node
CIP
Node
CIP
Node
CIP
Node
Gateway BGateway B
Cellular IP
Node
Cellular IP
Node
CIP
Node
CIP
Node
CIP
Node
CIP
Node
Domain A
Domain B
MIP
registration
CIP updateMedia
Inter Domain handoff
(SIP/MIP variants)
Optimization for Media Redirection
• Forwarding of in-flight data
– Buffering
– Small group multicasting
– Copy and Forwarding
Related Work• Buffering at the source
– Rosenberg et al, Collins et al – FEC, AVT
• Buffering at the destination
– Playout Buffer for RTP
• Buffering in the middle of the network
– Perkins et al – RFC 2354, Optimized Smooth Handover (MIPv4)
– N. Moore et al, Krishnamurthy et al – MIPv6
– M. Khalil et al - MIPv4
– Mobility Anchor Point
• Buffering at the edges
– Koodli et al – FMIPv6
– IAPP ( Layer 2 – 802.11)
Overview of Buffering Scenarios
Buffer Node
Post Handoff Traffic
with route optimization
Pre Handoff
Traffic
Buffered traffic
New Network Previous Network
Mobile Node
Correspondent Node
Flushed Traffic after
handoff
Post Handoff Traffic
with care-of-address
Signaling
Access
Router (BN)
Access Router
Buffering Node
Pre Handoff
Traffic
Buffered traffic
New Network Previous Network
Mobile Node
Correspondent Node
Flushed Traffic after
handoff
Post Handoff Traffic
Signaling
Access
Router (BN)
Access Router
Buffering Model with Previous Access
Router as BN
Packet Buffering with Next Access Router
as BN
Buffer Node
Post Handoff Traffic
Pre H andoff
Traffic Buffered traffic
New Network Previous Netw ork
Mobile Node
Correspondent Node
Signaling
Access
Router Access Router
Buffer Node
Buffered traffic
New NetworkOldPrevious Network
Mobile Node
Correspondent Node
Flushed Traffic after handoff
Signaling
Access Router (BN) Access Router
Buffer Node
Buffered traffic
New NetworkOldPrevious Network
Mobile Node
Correspondent Node
Flushed Traffic after handoff
Signaling
Access Router (BN) Access Router
End System Buffering
Buffering during handoff
Source
Mobile
Buffer Length (B)
Packet 1 throughN (Pre-handoff)
Mobile
N+1
N+2
N+3
StartBuffer Flush
Buffer
Packet N+4 onwards(post-handoff)
1…NN+1, …
End-to-end packet delay due to buffering
0
20
40
60
80
100
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
Packet Number
En
d-t
o-e
nd
dela
y
End-to-end packet
delay due to buffering
IDMP Fast Handoff
Fundamentals•On detecting the impending change in point of attachment, the MN (or optionally SA) sends a MovementImminent message to the MA.–No additional information keeps the message very
short.
•On receiving this message, the MA starts multicasting all inbound packets by tunneling them to all neighboring SAs.–Pre-configured list of SAs to which MN can move.
Fast Handoff Operational View
Fast Handoff in MA-based
GCoA mode
MovementImminentMovementImminent
MN_addrMA data
MN_addr
Multi-cast MN_addr data
Multicasting Begins
Buffered Packets
Agent Advt.
Local Regn Request
Local Regn Response
Data Packets
MASA_oldMN
SA_new
Cross Layer TechniquesIEEE 802.21
Scope of IEEE 802.21
•The current scope includes a Media Independent Handover Function (MIHF) consisting of three basic components– Event Service (ES)– Command Service (CS) – Information Service (IS)
•Support for multiple access technologies (e.g., 802.3, 802.11, 802.16, and Cellular (3GPP and 3GPP2))
•Support for both network and device initiated handovers
What is Media Independent Handover?
•Media Independent Handover (MIH) is to facilitate handover optimization between heterogeneous media by providing
–Link layer intelligence and
–Network information to upper layers
• Media Independent Handover (MIH) is not to design another mobility management protocol rather help them to perform handover seamlessly by offering a better user experience
IEEE 802.21 OverviewThe goal of IEEE 802.21 is to facilitate mobility management protocols such that following handover requirements are fulfilled
• Service Continuity –Minimize the data loss and break time without user intervention
• Application Class–Supporting applications of different tolerance characteristics
• QoS–Specify means of obtaining QoS information of the neighboring networks
• Network Discovery and Selection –Network information could include information such as link type, link
identifier, link availability, link quality
–Selection of appropriate network based on required QoS, cost, user preference
• Security–Specify means of security information to be made available to the upper
layers
• Power Management–Real-time link status, efficient scanning provide proper battery power
management
MIHF and Its Interactions with Lower and Upper Layers
Lower Layers (L2 and below)
MIH Function
802.3 802.11 802.16 3GPP(WCDMA)
3GPP2(CDMA2000)
Upper Layers (L3 and above)
SIP MIPv4 MIPv6 HIP L3MP
MIH Events
Link Events Link Commands
MIH Commands Information Service
Information
Service
Cross-layer feedback in IETF Multimedia Protocol Stack
Application (Audio, Video, Data)
Codecs (H.261)SAP SIP
RTP RTCP
H.323
TCPUDP
SCTP
SDP
MIP MIPv6 ICMP IGMP
PPPAAL 3/4
CDMA/GPRS802.3802.11
CSMA/CA CSMA/CD
SONETTX powerModulation
BER
SNR,
switchingLINK status
RoutingHandoff
TCP Retransmission,
RTCPFeedback
Re-negotiate
Bw, codec
Adaptive Application User Needs, Requirement
CIP
User
AAL3/4
RIP OSPF
Petri-Net Modeling for Mobility Systems
Net-within-a-System net
Layer 2
Layer 3
Application
Layer
Layer 2Event
Layer 3Event
Layer 4Event
Enter Mobility Event
Leave layer 2
Disconnected
Leave layer 3
Leave mobilityevent
Enter layer 3
Enter layer 2
transition
Connected
SNR goes belowa threshold
State
Service
discovery
Scanning is performed
Selected
L2 authenticationperformed
Authenticated
Location
L3 discovery
L3 addressacquisition
DAD
configuration
L3 authenticationperformed
authenticated
Extraneous action
buffering
BU performed
Forwarding
Use Case: Using Multiple Radios
Ne
tw
or
k
Ty
pe
S
SI
D/
C
ell
ID
B
S
SI
D
Op
er
at
or
Se
cu
rit
y
N
W
C
ha
nn
el
Q
o
S
Ph
ysi
cal
La
yer
Dat
a
Rat
e
GSM
13989
N/A
AT&T
NA NA 1900
N/A
N/A 9.6 kbps
802.16d
NA
NA
T-Mobile
PKM
EAP-PEA
P
11
Yes
OFDM
40 Mbp
s
Wakeup WLANDownload over WLANShutdown GPS
Café
Airport
Zone 1 Zone 2 Zone 3
Zone 4 Zone 5 Zone 6
Zone 7 Zone 9
Wi-Fi
Wi-MAX
WLAN Link Going Down.
Switch to WiMAXDownload over WiMAXShutdown WLANWakeup GPS
Zone 8
Wi-Fi
Connect to WLAN
Battery level lowShutdown WiMAXDownload over GSM/GPRS
Wakeup WLAN
Wi-MAX
Shutdown GPSStart Download over WLAN
Network
Type
SSID/
Cell ID
BSSID Operator Security NW Channel QoS Physical
Layer
Data Rate
GSM 13989 N/A AT&T NA NA 1900 N/A N/A 9.6 kbps
Network
Type
SSID/
Cell ID
BSSID Operator Security NW Channel QoS Physical
Layer
Data Rate
GSM 13989 N/A AT&T NA NA 1900 N/A N/A 9.6 kbps
802.11b Café 00:00:… Café .11i EAP-PEAP
6 .11e OFDM 11 Mbps
Network
Type
SSID/
Cell ID
BSSID Operator Security EAP
Type
Channel QoS Physical
Layer
Data Rate
GSM 13989 N/A AT&T NA NA 1900 N/A N/A 9.6 Kbps
802.11b Airport 00:00:… Airport .11i EAP-PEAP
6 .11e OFDM 11 Mbps
Radio State
GSM
WLAN
WiMAX
GPS
Radio State
GSM
WLAN
WiMAX
GPS
Radio State
GSM
WLAN
WiMAX
GPS
Radio State
GSM
WLAN
WiMAX
GPS
Radio State
GSM
WLAN
WiMAX
GPS
Radio State
GSM
WLAN
WiMAX
GPS
Radio State
GSM
WLAN
WiMAX
GPS
802.21 and MP Enabled Seamless Mobility Deployment Scenario
Courtesy: Vivek Gupta, IEEE 802.21 chair
Link Layer Events
Event
Identifier
Event Type Event Name
1 State Change Link Up
2 State Change Link Down
3 Predictive Link Going Down
4 State Change Link Detected
5 State Change Link Parameters Change
6 Administrative Link Event Rollback
7 Link Transmission Link SDU Transmit Success
8 Link Transmission Link SDU Transmit Failure
9 Link Synchronous Link Handoff Imminent
10 Link Synchronous Link Handoff Proceeding
11 Link Synchronous Link Handoff Complete
Link CommandsNo Link Command Local,
Remote Media Types
Comments
1 LinkPowerUp L All Power Up a link
2 LinkPowerDown L All Power down a link
3 LinkConfigure L All Configure a specific interface
4 LinkConnect L All Connect on a specific link
5 LinkDisconnect L All Disconnect the connection on specified link
6 LinkSleep L All Put link into sleep mode
7 LinkScan L All Scan the link for network PoA
8 LinkPoll L All Poll a specific link
MIH Command List
No MIH Command Local,
Remote
Media Types
1 MIH Poll L, R All
2 MIH Switch L, R All
3 MIH Configure L, R All
4 MIH Scan L, R All
List of GNI Information Elements Name of the information element Description Media
Types
List of networks available List all network types that are available given a location or POA information
All
Location of POA Geographical Location, Civic address, PoA ID All
Network standards supported List of all available transmission technologies available
All
Network Identifier Unique ID of the network or network provider All
Operator Name of the network provider All
IP Version Indicates the version Internet Protocol used All
Roaming Partners List of direct roaming agreements All
Cost Indication of costs for service/network usage All
SLAList Service level Agreement list All
List of LLI Information Elements
Name of the Information Element Description Media Types
Neighbor Information Neighboring network information, measurement report
All
Security Link layer security supported All
Quality of Service Link QoS parameters All
AccessRouterInfo Access Router Parameters All
List of HLI Information Elements
Name of the Information Element Description Media Types
IMS Access (MMS, SMS, Presence, Instant Message, Push-to-Talk, …)
Indication whether specific service is supported or not
N/A
ISP Supported Internet Service Provider that provides the access to internet
N/A
Location based services List of Local services that are available given a location
N/A
VPN Supported Network enables VPN services
N/A
MIP Supported Network enables MIP version and services
N/A
Use of NAT NAT is used for internet access
N/A
Optimization Case Studies
Initial Experimental Results on Mobility Optimization(Systems Evaluation)
Experimental Validation of Mobility OptimizationCase Studies
Following are the experimental case studies where we have been able
optimize the handoff delay and reduce the packet loss by deploying several
Optimization Techniques discussed above
• Case I - Optimizing data path between CH and MH
• Case II - Optimizing Binding Update
• Case III - Optimizing Layer 3
• Case IV - Optimizing Security Association
• Case V - Make-before-Break Technique
• Case VI - Maintaining Security Association
• Case VII - Media Independent Pre-authentication proactive handover and buffering
• Case VIII – Optimized IMS Handoff• Case IX - Multicast Mobility
Media-independent Pre-Authentication
• MPA is:
–a mobile-assisted higher-layer authentication,
authorization and handover scheme that is
performed a-priori to establishing L2 connectivity to
a network where mobile may move in near future
• MPA provides a secure and seamless mobility
optimization that works for
–Inter-subnet handoff
–Inter-domain handoff
–Inter-technology handoff
•Use of multiple interfaces
• MPA works with any mobility management protocol
Functional Components of Proactive
Handoff
1) Pre-authentication/authorization
– Used for establishing a security association (SA) between the
mobile and a network to which the mobile may move
2) Pre-configuration
– Used for obtaining parameters (e.g., an IP address) from the
network to which the mobile may move
– The SA created in (1) are used to perform secured configuration
procedure
3) Secured Proactive Handover (PH)
– Used for sending/receiving IP packets from the current network
using the pre-configured parameters of the new network
Media-independent Pre-Authentication (MPA)• MPA is a mobile-assisted higher-layer authentication,
authorization and handover scheme that is performed a-priori to establishing L2 connectivity to a network where mobile may move in near future
• MPA provides a secure and seamless mobility optimization that works for Inter-subnet handoff, Inter-domain handoff and Inter-technology handoff
• MPA works with any mobility management protocol
TimeConventional
Method
AP DiscoveryAP DiscoveryAP DiscoveryAP DiscoveryAPAPAPAP
SwitchingSwitchingSwitchingSwitching
MPA
Pre-authentication
IP address
configuration
& IP handover
Time
Client
Authentic
ation
Packet Loss Period
Media Independent Pre-authentication -
Seamless Handoff (a deployment scenario)
AA CA
MN-CA keyAR
Network 3
AR
AA CA
MN-CA key
Network 2
INTERNETInformation
Server
Mobile
Current
Network 1AR
AP1 Coverage Area AP 2 & 3 Coverage Area
AR
Network 4
CN
AP3AP2AP1 CTN
TN
CTN – Candidate Target Networks
TN – Target Network
Home
Network HA
MPA Overview
CN: Correspondent NodeMN: Mobile NodeAA: Authentication AgentCA: Configuration AgentAR: Access Router
AA CA
A(X)
2. DATA [CN<->A(Y)] over proactive handovertunnel [AR<->A(X)]
AR
L2 handoff procedure
Domain X Domain Y
CN
Data in new
domain
1. DATA[CN<->A(X)]
MN-CA key
Preconfiguration
pre-authentication
MN-AR key
3. DATA[CN<->A(Y)]
Data in old
domain
MN
A(Y)
BU
Proactive handovertunneling end
procedure
Tunneled Data
MN
Proactive Handoff Experimental Results (Case III) Mobility Type MIPv6
Handoff
Parameters
Buffering Disabled
+ RO Disabled
Buffering
Enabled
+ RO
Disabled
Buffering Disabled
+ RO
Enabled
Buffering
Enabled
+ RO
Enabled
Buffering
Disabled
Buffering
Enabled
L2 handoff (ms)
4.00 4.33 4.00 4.00 4.00 5.00
Avg. packet loss
1.33 0 0.66 0 1.50 0
Avg. inter-packet interval (ms)
16.00 16.00 16.00 16.00 16.00 16.00
Avg. inter-packet arrival time during handover (ms)
n/a 45.33 n/a 66.60 n/a 29.00
Avg. packet jitter (ms)
n/a 29.33 n/a 50.60 n/a 13.00
Buffering period (ms)
n/a 50.00 n/a 50.00 n/a 20.00
Avg. Buffered Packets
n/a 2.00 n/a 3.00 n/a 3.00
SIP Mobility
Performance (MPA-Non-MPA) – Single
I/F• MPA
– No packet loss during pre-authentication, pre-configuration and pro-active handoff before L2 handoff
– Only 0 packet loss, 4 ms delay during handoff mostly transient data
• Includes delay due to layer 2, update to delete the tunnel on the router
• We also reduced the layer 2 delay in hostap
Driver
• L2 delay depends upon driver and chipset
• non-MPA
– About 200 packets loss, ~ 4 s during handover
• Includes standard delay due to layer 2, IP address acquisition, Re-Invite, Authentication/Authorization
– Could be more if we have firewalls also set up
MPA Approach
Non-MPA Approach
handoff
802.11 802.11
4 s
Handoff Delay
~ 18 s
802.11 CDMA
Handoff Delay
16 s
802.11 CDMA
a. MIP-based Non-optimized handoff
b. SIP-based Non-optimized handoff
c. MPA and 802.21 assisted optimizedhandoff
802.11 CDMA
Optimized handoff delay with MPA (Multiple I/F)
Optimized Handoff - Audio
Optimization in IMS Testbed
P-CSCFP-CSCF S-CSCF
AS
HSS
I-CSCF
PDSN HA
VN1-re2VN2-re3
802.11b 802.11b
Visited Network 1
Visited Network 2
DHCPDHCP
RAN Emulator
Mobile Node
K6Router
192.168.6.0/24192.168.8.0/24
6.2
6.1
8.2HN-HA
HN-AS-SCSCFHN-HSS-ICSCF
VN1-PCSCF
VN1-DHCP
VN2-PCSCF
VN2-DHCP
VN2-PDSN
VN1-PDSN
VN1-RE-12
PDSN
RAN Emulator
VN2-RE-21
8.1
Mobile Node
Domain: kddi.testbed
VN1-re1
802.11b
Home Network
IPTV Server
HN-IPTVServer
RAN Emulator
VN1-RE-11
6.3
PDIF
VN2-PDIF
VN2-re4
802.11b
::5::10::15::25::5::10::15
3ffe:2::/64
3ffe:1::/643ffe:5::/64
::1
::1
::1
::10::5
3ffe:5::30
(Mobile IP case) mh2
3ffe:5::35
(Mobile IP case)
::20::15::25
PDIF
VN1-PDIF
VN1-re5
802.11b
<PPP address on PDSN>
mh1 3ffe:11::MAC/64
mh2 3ffe:11::MAC/64
<PPP address on PDSN>
mh1 3ffe:22::MAC/64
<Address on PDIF>
mh1 3ffe:33::MAC/64
<Address on PDIF>
mh1 3ffe:44::MAC/64
PCRF
VN2-PCRF
::30
VN1-PCRF
::30
PCRF
To visited domain
mh3
3ffe:5::40
(Mobile IP case)
Mobile NodeMobile Node3ffe:5::30
(Mobile IP case)
Current demonstration• P-CSCF fast handover
– Non-Optimized– Reactive– Proactive
• Optimized Roaming– Dual anchoring– Home address anonymity
Functions-Protocol MappingFunctions Protocols
Signaling, Personal Mobility SIP
Policy Control, Feature Interaction
Diameter
Mobility Management MobileIP[v4,v6], SIP, ProxyMIPv6
Security IPSec, L2 Security
Server Configuration DHCP
Address configuration Stateless Autoconfig, DHCPv6
Streaming, IPTV RTSP
Name Resolution DNS
Multicast Routing PIM-SM
Multicast Mobility Remote Subscription based
Non-Optimized Mode of Operation
MIP Registration Request
MN old P-CSCF new P-CSCF S-CSCF
401 Auth. (Reg.) - new Key, vector
REGISTER (MN address)
Medialoss
Radio
handoff
old DHCP new DHCP HA
MIP Registration Reply
Non Encrypted
Non Encrypted
new SA setupnew SA setup
Open Gate
Createa new context
Re-INVITE
401 Auth. (Reg.) - vector
Encrypted by new SA 200 OK (Reg.)
REGISTER (Auth, MN address)
200 OK (Reg.)
REGISTER (Auth, MN address)Encrypted by new SA
Encrypted by new SA
Encrypted by new SA
REGISTER (MN address)
DHCP Inform (pcscf, pcscf-neighbor)
DHCP Ack (new P address, neighbor P addresses)
200 OK (Reg.)
Re-INVITE
200 OK (Reg.)
Reactive Mode of Operation
M IP Registra tion Request
M N old P -C S C F new P -C SC F S-C SCF
Do C on text T ransfer (new P address, M N address)
401 Au th. (R eg.) - new K ey, vec tor
C ontext T ransfer (M N In form ation)
REG ISTE R (MN address )
Med ia
loss
R adio
hando ff
O pen G ate
R EG IST ER (MN address)
o ld D HC P new DHC P H A
M IP Registra tion Reply
R e-C reatethe context
Non
Encrypted
Non
Encrypted
new SA setup
401 A uth. (R eg.) - vec tor
Encryp ted by
new SA200 O K (R eg.)
REG ISTE R (Auth, M N address )
200 O K (Reg.)
REG IST ER (Auth, M N address)Encryp ted by
new SA
new SA s etup
C ontext T ransfer Ack (MN address)
DH C P Inform (pcscf, pcscf-neighbor)
DH C P Ack (new P address, neighbor P addresses)
Proactive Mode of Operation
M IP R eg istra tion Request
M N old P-C SC F new P-C SCF S-CSCF
M oveNotify (new P address, MN address)
401 Auth . (Reg.) - new Key, vector
Context Transfer (old Key, M N Inform ation)
R EG ISTER (M N address)
new SA setup
Re-Createthe context
Media
loss
Radiohandoff
O pen G ate
401 Auth . (Reg.) - vector
REG ISTER (MN address)
old DHC P
Encrypted by
new SA
new DHCP HA
M IP R eg istra tion Reply
Encrypted by
old SA
o ld SA setupEncrypted by
old SA
Encrypted by
old SA
200 OK (Reg.)
R EG ISTER (Auth , M N address)
200 O K (Reg.)
REGISTER (Auth, MN address)Encrypted by
new SA
new SA setup
Context Transfer Ack (M N address)
D HCP Inform (pcscf, pcscf-neighbor)
D HCP Ack (new P address, neighbor P addresses)
Basic Functional Components During
Handoff in IMS/MMD
•Handoff related functions in IMS
– Layer 2 Configuration
– Layer 3 Configuration
– Mobility Binding
– Session Registration
– Security Association
– Session Maintenance
– Media control on PDSN
0 3000 6000 9000 12000
Proactive
Reactive
Non-Optimized
Typ
es o
f H
andoff
Time in ms
PPP Termination
Layer 2 Delay
PPP Activation
MIP-Solicitation
MIP-Binding Update
DHCP Trigger
DHCP Inform
SIP Trigger
SIP+Security
Media Redirection
Figure 1: Levels of Optimization
MIPv6-SIPM-ProxyMIPv6 in IMS
0 2000 4000 6000 8000 10000
Proxy MIPv6 (cdma2000)
Proxy MIPv6 (WiFi)
SIP mobility (cdma2000)
SIP mobility (WiFi)
MIPv6 (cdma2000)
MIPv6 (WiFi)
Handoff time [ms]
IEEE 802.11b handoff PPP negotiation
Layer 3 address configuration Binding update
SIP server address configuration SIP Registration
SIP re-INVITE/Gate open
MIPv6-SIP-ProxyMIPv6 results –effect of RAN delay
0
2000
4000
6000
8000
10000
12000
14000
16000
18000
20000
50 100 150 200 250 300 350 400 450 500
RAN delay [ms]
Han
doff
tim
e [m
s]
MIPv6 SIP mobility Proxy MIPv6
Multicast Mobility (remote Subscription)
Internet
Home Network
HA
MN
Visited Network 1
DHCP
MN
Multicast Tree
Visited Network 2
MN
MR1 MR2
DHCP
Handover
Source
Fast-handoff with Multicast mobility
S1 S2p1 p2
BS0BS1
Sources
Backbone
Ad server
Local
Server
m1
m2
Local
Program
RTSP
Ad server
Local
Server
m1
m2
Local
Program
RTSP
BS2
M-Proxy
(P1,a1) (P2,a2)P2,a2
P2,a3
S0
S1
(a1,a2)
(a3)
• Fast-handoff for the mobiles
• QoS negotiation
RTCP
IGMP
Layer 2 Handoff for Multicast
0
1
2
3
4
5
0 200 400 600 800
Time in Seconds
Pro
toc
ols RTP
DRCP
Router Query
Q.Response
IGMP-802.11 (Subnet) Handoff
0
1
2
3
4
5
0 200 400 600 800 1000
TIme in Seconds
Pro
toc
ols
In
sta
nc
e a
t M
ob
ile
RTP
DRCP
Router Query
Q.Response
JOIN Latency JOIN Latency
Subnet
handoff
Subnet
handoff
Ping-Pong Ping-Pong
There is no JOIN Latency but Leave latency
inherent
JOIN Latency is about 60 seconds
Proxy assisted subnet handoff
0
1
2
3
4
5
0 200 400 600 800
Time in Seconds
Pro
toc
ols
at
mo
bil
e
RTP
DRCP
Router Query
Q.Response
JOIN latency is almost zero
Leave latency is still an issue
LEAVE latency during 802.11subnet handoff
0
1
2
3
4
5
120 180 240 300 360 420 480 540 600
Timr in Seconds
Pro
toc
ols RTP
DRCP
Router Query
Ping Mobile
Maximum leave latency is about 3 min.
Leavelatency
Proactive Proxy-based handoff for Multicast in 802.11
environment (Case III)
Bluetooth
APCDMA
Corresponding Host
Router/ Foreign Agent Router/ Foreign Agent
802.11
AP
Home Agent
BackboneNetwork
Visiting Network A Visiting Network B
Home Network
Ether
Bridge
Video StreamVideo Stream
Multi-Interface Mobility Management (Make-before-Break)
IntraIntra--Subnet MobilitySubnet MobilityInterInter--SubnetSubnet
MobilityMobility
Movement type Cellular-802.11b
802.11b –
Cellular
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
Operation 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
Packet Transmission Delay for Voice Traffic
0.00000010
0.00000100
0.00001000
0.00010000
0.00100000
0.01000000
0.10000000
1.00000000
36
46
0
37
80
0
39
14
0
40
48
0
41
82
0
43
25
2
45
58
6
49
31
7
52
62
4
56
93
3
60
94
0
62
28
0
63
62
0
Packet Numbers
Tra
ns
mis
sio
n D
ela
y i
n (
Lo
g S
ca
le)
Transmission Delay
802.11
Cellular
802.11
Packet Transmission Delay for Voice Traffic
0.00000010
0.00000100
0.00001000
0.00010000
0.00100000
0.01000000
0.10000000
1.00000000
36
46
0
37
80
0
39
14
0
40
48
0
41
82
0
43
25
2
45
58
6
49
31
7
52
62
4
56
93
3
60
94
0
62
28
0
63
62
0
Packet Numbers
Tra
ns
mis
sio
n D
ela
y i
n (
Lo
g S
ca
le)
Transmission Delay
802.11
Cellular
802.11
Inter-Packet Delay Variation betw een CH and MH (Voice)
0.0010
0.0100
0.1000
1.0000
10.0000
36
46
0
37
48
4
38
50
8
39
53
2
40
55
6
41
58
0
42
60
4
44
01
2
46
01
9
48
86
7
51
67
1
54
17
2
58
27
9
60
85
2
61
87
6
62
90
0
Packet Numbers
Inte
r-P
ac
ke
t D
ela
y d
iffe
ren
ce
(lo
g s
ca
le)
Delay Variation
802.11 802.11
Inter-Packet Delay Variation betw een CH and MH (Voice)
0.0010
0.0100
0.1000
1.0000
10.0000
36
46
0
37
48
4
38
50
8
39
53
2
40
55
6
41
58
0
42
60
4
44
01
2
46
01
9
48
86
7
51
67
1
54
17
2
58
27
9
60
85
2
61
87
6
62
90
0
Packet Numbers
Inte
r-P
ac
ke
t D
ela
y d
iffe
ren
ce
(lo
g s
ca
le)
Delay Variation
802.11 802.11
(a) Packet Transmission Delay(b) Inter-packet departure and arrival delay variation for
CBR (Voice)
Mobile IP with VPN
SIP-based multi-interface mobility management
Experimental results for handoff delay with multiple Interfaces
without optimization
SIP Mobility (MIMM) – Make-before-break (802.11 – CDMA)
MN: WLAN - Eth0 – 10.1.10.2CDMA - PPP0 – 166.157.116.186
CN – 165.254.55.2
•Jitter observed in Cellular Network-Several Re-INVITE retransmissionin CDMA network-Packets are received in eth0 duringSIP Re-INVITE sequence- No packets are lost during the handoff
MNCN
(ppp0)
RTP (28790)16.202
16.240
16.242RTP (28791)
(eth0)
(ppp0)
(eth0)
Re_INVITE (IP1)
Re-INVITE (Re-trans) –IP116.750(ppp0)
RTP (28792)16.285(eth0)
16.322
16.362
RTP (28793)
RTP (28794)
Re_invite (Re-trans)- IP117.761
RTP
RTP
(eth0)
(eth0)OK
19.639(ppp0)RTP
(eth0)
19.758ACK
(ppp0)RTP
RTP(eth0)
(eth0)28888
RTP 2888920.549(ppp0)
20.122
20.669(ppp0)RTP 28890
Handoffdelay
20.769(ppp0)
20.869
(eth0)
(eth0)
MIP with Make-before-break (802-11-CDMA)MN HA CN
RTP 644407eth0 39.594
RTP 644408eth0 39.630
RTP 644405
RTP 644406
Mobile IP (reg)eth0 39.514
ppp0 39.520
eth0 39.551
RTP 644409eth0 39.674
RTP 644410ppp0 40.059
ppp0 40.119RTP 644411
Mobile IP (Rep)
ppp0 40.219
ppp0 40.339RTP 644412
ppp0 40.629RTP 644413
RTP 644414ppp0 40.649
RTP 644415ppp0 40.659
Tunnlled data
Non-tunneled data
Signaling
CN – 207.3.232.223, MN – WLAN – eth0 – 10.1.10.2
CDMA – PPP0 – 166.157.32.161
Data Sentat 40 ms interval
Jitter in cellular
eth0 – wavelan InterfacePpp0 – cellular interface
Deployment Roaming Scenarios
vDHCPvP-CSCF
hMN
hAGW
hMN
Home domainVisited domain
vS-CSCF
vASvAAA
hMNhMN
Home Local MobilityGlobal MobilityVisited Local Mobility
Internet
hMN hMN
hAGWhAGW
Trust domain
vPCRF
hDHCPhP-CSCF
hS-CSCF
hAShAAA
hPCRF
vAGWvAGWvAGW
hHAvHA
Roaming Movement Matrix
MIPv6
PMIPv6/MIPv6
PMIPv6/MIPv6
Simple IPv6MIPv6 (Case IV)
MIPv6
PMIPv6/MIPv6 (Case VI)
Simple IPv6PMIPv6/MIPv6 (Case III)
MIPv6
PMIPv6/MIPv6
Simple IPv6Simple IPv6CMIPv6
MIPv6
Simple IPv6MIPv6
MIPv6
PMIPv6/MIPv6
Simple IPv6 PMIPv6/MIPv6 (Case II)
MIPv6
PMIPv6/MIPv6 (Case V)
Simple IPv6 Simple IPv6 (Case I)Simple IPv6
Visited DomainHome DomainMN Stack
This case may not happen.
Multi-Media Session Continuity (3GPP)• The MMSC solution will provide IMS level multimedia session
continuity when the user is moving between 3GPP access systems or when the user is moving between 3GPP and non-3GPP access systems with minimum disruption
• Two basic scenarios are PS-PS and PS-PS in conjunction to PS-CS
Non-3GPP
(e.g. WiMAX)
E-UTRAN
Intermediate
IMS elements
MGCF
P-CSCF-a1
Voice + data
Voice + data
P-CSCF-a2
UE-1
UE-2
Voice + data
WLAN
UTRAN/
GERAN
Intermediate
IMS elements
MGCF
P-CSCF-a1
Voice + data
Voice + data
Data
P-CSCF-a2
Voice
UE-1
UE-2
PS-PS Scenario
PS-PS in conjunctionto PS-CS Scenario
Mobility Modeling
217
Scheduling
of handover
operations
Relevant
optimization
principles
Example experimental mobility systems Potential
Target
Mobility
System
SIP-based
Fast
handoff
Mobile
VPN
Media
Independent
Pre-authentication
Simultaneous
Mobility
Optimized
handoff
In IMS
Muti-layer
Mobility
Multicast
fast
handoff
Sequential Direct path between
CH and MH X
Limit binding update
between CH and MH X X
Maintain Security
association
between end-points
X
Anchor-based
ForwardingX X
Post-handoff triggers X
Proactive Pre-handoff triggers X X
Proactive network
discovery X
Proactive
authentication X
Proactive identifier
configuration X
Proactive
binding updateX X
Dynamic Buffering X
Proactive context
transfer X
Parallel Discovery of Layer 2
and Layer 3 PoA X
Binding update X
Optimized mobility system design
Mobility model Problem: In the absence of any formal mechanism it is difficult to predict or
verify the systems performance of un-optimized handover or any specific handoff optimization technique
Proposal
• Analyze the basic primitives of a handoff event
• Model the handoff-related processes as Discrete Event
Dynamic Systems (DEDS)
• Deterministic Timed Transition Petri Net (DTTPN) to build various un-optimized mobility models and their associated optimization techniques
Key advantages :
• This model can predict systems performance for optimized handoff operations
• This model can design optimal path for sequence of execution of events based on expected performance and resource constraints
• This model can verify systems behavior (e.g., deadlocks) during handover
218
Framework for Systems Optimization
Design a Generalized Systems Model to characterize
Mobility Optimization
• List a common set of properties that get affected (changed)
during different types (micro, macro, domain) mobility
• Need a generalized Systems Model to represent these
Mobility experiments
– A Systems Model for mobility optimization can be
characterized as a Discrete Event Systems Model
– An FSM model can be used to model the state transition
for mobility optimization
• Conduct a performance evaluation using this generalized
model (e.g., Timed Petri Net)
Systems Optimization Approach • We model mobility events as a set of discrete state transition events
within a layer and between layers
• Mobility events contribute to the change in state (e.g. Discrete State Events) within a mobile due to layered transition
• State transitions take place within a layer and between layers during mobility events
• We propose various handoff optimization techniques – Proactive, Reactive, Parallel– That help reduce the handoff delay at different layers– Mitigates effect of handoff delay (i.e., packet loss), jitter
• We map our optimization techniques to the mobility system model
• We perform experiments and simulation to show the implementation results for the following cases
Pa Pb
Pa Pb
Pa
Pb
Pa
Pb
tc
Pa
Pb
pb
pa
tc
tc
ta tc tb
ta tbta
tc tb
tc ta
tb
ta
tb
pa starts before pb
pa meets pb
pa overlaps pb
pa during pb
pa starts pb
pa finishes pb
pa starts with pbpa
pb
tc
tb
tc ta
ta
tb
Timing Diagram for sequence of events
Petri Net Primitives
t1 t2
b. Conflict
P1
p1
p2
p1
p2
t1
p1
p2
t1
t2
t3
d. Synchronization
f. Confusion
P1 t1 t2 P3
a. Sequential
c. Concurrent
p1
p2
t1
t2
P3
e. Merging
p1
p2 p3
t1
t2
g. Mutual exclusiveh. Priority
Sample Handover OptimizationExample (1) - Proactive Handover
Mobility Type
Mobile IPv6 SIP mobility
Handoff
Parameters
Bufferin
g
Disable
d
+ RO
Disable
d
Buffering
Enabled
+ RO
Disabled
Buffering
Disabled
+ RO
Enabled
Buffering
Enabled
+ RO
Enabled
Buffering
Disabled
Buffering
Enabled
L2 handoff (ms)
4.00 4.0 4.00 4.00 4.00 4.00
L3 handoff
(ms)
1.00 1.00 1.00 1.00 1.00 1.00
Avg. packet loss
1.3 0 0.7 0 1.50 0
Avg. inter-packet interval (ms)
16.00 16.00 16.00 16.00 16.00 16.00
Avg. inter-packet arrival time during handover (ms)
21 45 21 67 21 29.00
Avg. packet jitter (ms)
n/a 29.00 n/a 51.00 n/a 13.00
Buffering period (ms)
n/a 50.00 n/a 50.00 n/a 20.00
Avg. Buffered Packets
n/a 2.00 n/a 3.00 n/a 3.00
Results: Media independent proactive handoff
802.11802.11
4 s
223
Non-optimized handoff (200 packets loss, ~ 4 s handover delay)
Media Independent Pre-auth handoff (No packet loss – 5 ms handoff delay)
802.11 802.11Interruption
AAA
nAR
L3 PoA
MN
AP1
L2 PoA
AP0
(L2 PoA)
Pre-authentication
Network ANetwork B
Pre-configuration
pAR
L3 PoA
Core
Network DHCPserver PANA
server
Buffering
module
Tunneling
module
MN
HA (MIP)Home
Network
Proactive
Handover
Tunnel
CN
Network C Network D
224
Sample Handover Optimization: Example (2) -
IMS
0 3000 6000 9000 12000
Proactive
Reactive
Non-Optimized
Typ
es o
f H
andoff
Time in ms
PPP Termination
Layer 2 Delay
PPP Activation
MIP-Solicitation
MIP-Binding Update
DHCP Trigger
DHCP Inform
SIP Trigger
SIP+Security
Media Redirection
DOMAIN
research.telcordia.com
P-CSCF P-CSCFS-CSCF
ASI-CSCF I-CSCFHSS
SPE
I-CSCF
InternetInternet
HUB
HUB
HUB
192.168.10.0/24
Mobile
Phone
Mobile
Phone
SIP-UA
mh3
URI: user3
SIP-UA
mh1
URI: user1
SIP-UA
mh2
URI: user2
PDSN
Gateway
FA
Gateway
PDSN
FA
HA
Sample Testbed
kddiv1kddiv2
802.11b802.11b
CH 8 CH 8
Home NetworkVisited Network 1Visited Network 2
Database Monitor
Packet Snooper
DHCP
HUB
CDMA 2000
RAN
Emulator
kddiw2
DHCP
HUB
CDMA 2000
RAN
Emulator
Mobile
192.168.20.0/24
192.168.30.0/24
Router
192.4.30.0/24
192.168.6.0/24
192.168.7.0/24
192.168.8.0/24
192.168.9.0/24
10.5
10.4 10.3 10.2
20.5 20.4 20.3 20.2
6.2
6.1
7.1
8.2
8.1
9.1
20.1
10.1
30.1
30.230.330.4
kddi1
kddi2
kddi3
kddi4kddi5kddi6
kddi7kddi8kddi9
kddigw2
kddigw1
kddiw1
213-111
Figure 2: Handoff delay with 3 levels of optimization
Figure 1: IMS Experimental Testbed
Components optimized
ConnectedP8
Disconnected
NetworkDiscovered
NetworkSelected
MobileConfigured
AuthenticatedSecurityAssociationEstablished
Updated
NetworkResourceDiscovery Network
SelectionDetectionProcess
NetworkConfiguration
AuthenticationProcess
Binding Update
MediaForwarding
P1 P2 P3
P4P5P6
P0
t1 t2t3
t4
t5t6t7
P7
Intra-domainBinding update
t8t9
BufferingRedirection
t0
p01
p02
p03
t01
t02
t03
t013
t04
Security AssociationProcess
Modeling Mobility Event as Discrete Event Dynamic Systems (DEDS)
Description of Places and TransitionsPlace Description
P0 Mobile is in disconnected state
P1 Network and resources discovered
P2 Target network selected
P3 Mobile is configured and registered
P4 Mobile is authenticated
P5 Security Association is established
P6 Binding Update is complete
P7 Intra-domain binding update is complete
P8 Mobile is connected state
Transition Description Time Delay
t0 Mobile gets disconnect trigger 1t
t1 Mobile discovers the network and resources at the new PoA 2t
t2 Mobile selects the network 3t
t3 Mobile goes through configuration and registration 4t
t4 Mobile goes through authentication process 3t
t5 Mobile goes through key derivation and security association process 2t
t6 Mobile goes through binding update process 6t
t7 Mobile goes through hierarchical binding update 5t
t8 Mobile gets redirected to the mobile 2t
t1
p1p0 t2
p2t3
Layer 2association
Router Solicitation Domain
advertisement
2
Mobile connected
p6
p3p4
p5
Channelavailable
(Resource: Battery Power) (Resource: CPU Cycles)(Resource: Bandwidth)
Petri net modeling: Handoff attachment process
t1p1
p0 t2p2
t3
p4p3 p5
3
1
IdentifierAcquisition
Duplicate Address Detection Address
Resolution
12
2
MobileConfigured
MobileAuthenticated
(Resource: Battery Power) (Resource: CPU cycles)(Resource: Bandwidth)
p6
Petri net modeling - Handoff configuration process
Dependency analysis among handover operations
Handoff Process Precedence Relationship
Data it depends on
P11 – Channel Discovery P00 Signal-to-Noise Ratio valueP12 – Subnet discovery P21,P22 Layer 2 beacon ID
L3 router advertisementP13 – Server discovery P12 Subnet address
Default router addressP21- Layer 2 association P11 Channel number
MAC address Authentication key
P22- Router solicitation P21, P12 Layer 2 bindingP23- Domain advertisement P13 Server configuration
Router advertisementP31 – Identifier acquisition P23,P12 Default gateway
Subnet address Server address
P32 – Duplicate addressdetection
P31 ARPRouter advertisement
P33 – Address resolution P32, P31 New identifierP41 – Authentication P13 Address of authenticatorP42 – Key Derivation P41 PMK (Pairwise Master Key) P51 – Identifier update P31,P52 L3 Address
Uniqueness of L3 addressP52 – Identifier verification P31 Completion of COTIP53 – Identifier mapping P51 Updated MN address
at CN and HAP54 – Binding cache P53 New Care-of-address mappingP61 – Tunneling P51 Tunnel end-point address
Identifier addressP62 – Forwarding P51, P53 New address of the mobileP63 – Buffering P62, P51 New identifier acquisition P64 – Multicasting/Bicasting P51 New identifier acquisition
229
Resource usage per mobility eventsSub transitions
Sub-operations Resource Consumption
Bytes exchanged
CPU samples
Power due to transmission(nanojoules)
t00 Layer 2 un-reachability test 43 5 51600
t01 Layer 3 unreachability 86 3 103200
t11 Discover layer 2 channel 109 3 130800
t12 Discover layer 3 subnet 110 4 132000
t13 Discover server 126 5 540000
t21 Layer 2 association 99 2 118800
t22 Router solicitation 70 4 84000
t23 Domain advertisement 226 4 271200
t31 Identifier acquisition 1426 5 1711200
t32 Duplicate address detection 164 6 196800
t33 Address resolution 60 3 72000
t41 Layer 2 open authentication 94 3 112800
t42 Layer 2 EAP 2842 6 3410400
t43 Four-way handshake 504 4 604800
t51 Master key derivation (PMK) 0 10 0
t52 Session key derivation (PTK) 0 6 0
t61 Identifier update 204 4 422400
t62 Identifier verification 148 6 177600
t63 Identifier mapping 0 8 0
t64 Binding cache 0 3 0
t71 Fast binding update 110 3 132000
t72 Local caching 0 6 0
t81 Tunneling 60 2 72000
t82 Forwarding 100 2 120000
t83 Buffering 120 3 144000
t91 Local id mapping 40 4 48000
t92 Multicasting/bicasting 192 2 230400 230
Petri net modeling of handoff processes
P00 t01
t11
t41
p11
p41
t13
p13
t42
p42
t21
p21
t22
p22
t12
p12
t23
p23 P52
t52 t51 P51
t53 p53
t64p64
t62
p62
t63
p63
t54 p54
p61
t31 t32 t33
p31 p32 p33
t70
Resource network capacity
Resource Battery
Resource CPU
PotentialParallelOperation
Connected
Verification of handover systems performance in Petri net
1.Reachability analysis to study behavioral characteristics (e.g., deadlocks)
2.Cycle time of Deterministic Timed Petri net
– Minimum cycle time (C) is an indicator of maximum system performance (delay vs. resource)
3.Floyd algorithm– S matrix is formed out of token loading matrix, transition
matrix and distance matrix
– Inspection of the diagonal elements of matrix “S” indicates whether systems meets the required performance
Scheduling of handoff operations
233
Association
Network
discovery
P11
t11
PA2
4-way
Handshake
(SA)
t1
t4 t5
P2 P3
Connected
Dis
connected
Pre-authentication
Current Network Target Network
PA1
PC
PB1
PD
t12
t13
AP
Key installation
P12
P1
Resources CPU
PC
Resource s
Battery
PB
4-way
handshake
completet3
t4 t5
P2
P3
t2
Scanning
Authentication
Network
Discovered
4-way
Handshake
Operation
P1
Resources
Network capacity
Mobile
Authenticated
Connected
Association
P0
P01
P02
2 2
t1
PA
PC CPU
Battery
PB
t3
t4
t5
P2
t2
Scanning
Authentication
Network
Discovered
4-way
Handshake
P1
Resources
Network Capacity
Mobile
Authenticated
Connected
P0
P01
P02
2
t1
P03
P3Association
4
PA
C. Proactive operations
B. Parallel operations – Level of concurrency =2
D. Parallel operations – Level of concurrency = 3
A. Sequential operations
Batterypower
scanning Authentication 4-way
Handshake
t2 t3 t4 t5
P2 P3 P4
Association
Connected
Mobile
Disconnected
Network capacity
CPUcycles
P1
PA
PB
PC
P0
t1Disconnection
Network
Discovered
Mobileauthenticated
1 token
Deadlocks in HandoffPA
CPU
Memory
PB
4-way handshakecompletet2
t3 t4
P2
P3
t1
Scanning
Authentication
Network
Discovered
4-wayHandshakeOperation
P1
ResourcesNetwork b/w
Mobile
Authenticated
ConnectedAssociation
P0
P01
P02
2
2
a. Deadlock due to resource constraint
Deadlock
b. Deadlock avoidance with additional resources
No -Deadlock
Deadlock analysis for simultaneous mobility
235
Deadlock Scenario (non-optimized) Deadlock verification (deadlock exists)
Deadlock avoidance with retransmission Deadlock verification (No deadlock)
Deadlock
Deadlock
01/06/2009 HICSS-42 236
Results from Cycle Time-based approach
Proactive
Concurrent
Sequential
Optimization
schedule
17117P1t1P2t4P3t5P1
4201420p0t1p01t2p1t3p3t4p0
4701470p0t1p1t2p2t3p3t4p4t5p0
Max Di/Ni
Minimum cycle
Time (ms)
NiDiRelevant
loop in Petri Net
t5
t4
t3
t2
t1
Transition
5 msAssociation
10 ms4-way handshake
50 msAuthentication
400 msScanning
5 msDisconnection
Trigger
Experimental
Results
Handoff
operation
C. Proactive – meets systems performance C=100
A. Sequential : Does not meet systems performance Cycle
time C =100
B. Concurrent: does not meet systems performance for C= 100
D. Concurrent– meetssystems performance C= 410
Verification of handoff systems performance using Floyd algorithm
237
Summary of rules of handoff optimization• In general, handoff event can be described as Discrete Event Dynamic Systems
where optimization at each sub-component level contributes to the overall optimization process
• Optimization techniques can primarily be defined as the following category– Sequential– Parallel– Predictive
• Minimize execution time by maximizing parallelism between various functional components– A system that introduces parallelism into a sequential program in such a way as to
maintain correct results is called determinate
• Reduction of signaling overhead during handoff operation at component level– Caching– Local redirection to reduce the traversal of signaling
• Proactive execution of handoff events• Cross layer triggers• Optimal buffering strategy to reduce packet loss• Local agent assisted media redirection• Research Issues
– Resource utilization for proactive handoff operations– Extent of parallelism between operations– Optimum handoff strategy
Conclusions• Several types of IP-based mobility protocols have evolved over the years
– End-to-end – Infrastructure-assisted – Mobile controlled vs. Network controlled– Mobility across layers
• There is no one-size-fit all solution for all types of application and deployment environment
• A specific mobility protocol needs to be chosen based on the following:– Type of application (e.g., Real-time, Non-Real-time)– Operating environment (e.g., intra-domain vs. inter-domain)– Extent of operator control
• Mobility protocols in their current form are not sufficient to support many of the delay sensitive real-time communication
• Optimization is needed at each layer to provide cellular like handoff quality• Optimization framework and fundamental rules of optimization can be applied to
any type of mobility protocol • Any deployment strategy needs to look at the fundamental rules of optimization
during the design process