IP-based Mobility and Handover Optimization (T3) Tutorial Authors: H. Anthony Chan, Ph.D. Huawei Technologies, USA [email protected]Ashutosh Dutta, Ph.D. NIKSUN Innovation Center, NJ, USA [email protected]Presented by Ashutosh Dutta IEEE WCNC 2011 Cancun, Mexico
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IP-based Mobility and Handover Optimization (T3)wcnc2011.ieee-wcnc.org/tut/t3.pdf · IP-based Mobility and Handover Optimization (T3) ... H. Anthony Chan, Ph.D. Huawei Technologies,
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• 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
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
• 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
– 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
•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
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
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