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Magazine????

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Abstract

1. A new method to support UMTS WLAN vertical
   handover using SCTP
2. Interworking techniques and architectures for
   WLAN 3G integration toward 4G mobile data
   networks
3. IEEE802.11 roaming and authentication in wireless
   LAN cellular mobile networks
4. ??

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Magazine 1

• A new method to support UMTS WLAN vertical
  handover using SCTP

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Note Abstract

• UMTS networks and WLANs
• Third-generation cellular networks
• UMTS/WLAN vertical handover problem
• Overview of Mobile SCTP
• VERTICAL HANDOVER PROCEDURES

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UMTS networks and WLANs

• UMTS
• wide-area connectivity
• low data rate
• high mobility
• WLANs
• higher data rate
• low mobility

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Third-generation cellular networks

• Both UMTS and WLANs
• WLAN offer higher bandwidth
• Mobile users accessing the Internet via UMTS/WLAN
  are free to move
• Handover between UMTS and WLANs
• MIP from IETF
• provides transparent support for host mobility
• routing architecture of mobile host
• Difficult to maintain the continuity between UMTS
  and WLAN
• Point of this article

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UMTS/WLAN vertical handover problem

• UMTS/WLAN vertical handover support via two
  types of SCTP
• single-homing asymmetric configuration
• dual-homing symmetric configuration
• Integrated UMTS/WLAN network architecture
• tightly coupled solutions connect UMTS and WLAN
• loose coupling solutions separate out UMTS and
  WLAN
• loose coupling offers several advantages over
  tight coupling

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Overview of Mobile SCTP (1)

• Originally for VoIP of 3GPP
• Reliability
• Multi-homing
• established over multiple interfaces identified
  by multiple IP addresses
• An SCTP association between two hosts, say, A and
  B, is defined as
• a set of IP addresses at A Port-A
• a set of IP addresses at B Port-B.

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Overview of Mobile SCTP (2)

• base version of SCTP cannot be used directly to
  support UMTS/ WLAN vertical handover
• Fortunately, the recently proposed DAR extension
  for SCTP enables the endpoints to add, delete, or
  change the IP addresses during an active SCTP
  association using address configuration (ASCONF)
  messages.
• basis of mSCTP

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Overview of Mobile SCTP (3)

• mSCTP
• Using for supporting UMTS/WLAN vertical handover
• capabilities to add, delete, and change the IP
  addresses dynamically during an active SCTP
  association

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Overview of Mobile SCTP (4)

• mSCTP Protocol architecture

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VERTICAL HANDOVER PROCEDURES (1)

• FS can also be configured for
• Single-homing The FS provides only one IP
  address to support handover.
• Dual-homing The FS allows more than one (usually
  two) IP addresses to support
• Handover procedure has three basic steps
• Add IP address
• Vertical handover triggering
• Delete IP address

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VERTICAL HANDOVER PROCEDURES (2)

• single-homing configuration

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VERTICAL HANDOVER PROCEDURES (3)

• dual-homing configuration

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SIMULATION RESULTS AND DISCUSSIONS (1)

• use network simulator ns-2 to perform the
  simulations and obtain
• set to be 384 kb/s for the UMTS link and 2 Mb/s
  for the WLAN link
• delay is set to 100 ms
• FTP traffic is started at the MC at time 1 s
• handover triggering process is activated at time
  5 s

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SIMULATION RESULTS AND DISCUSSIONS (2)

• simulation results
• UMTS-to-WLAN handover delay is 533 ms

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SIMULATION RESULTS AND DISCUSSIONS (3)

• simulation results
• WLAN-to-UMTS delay is 513 ms

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SIMULATION RESULTS AND DISCUSSIONS (4)

• throughput performance for vertical handover in
  both directions

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Magazine 2

• Interworking techniques and architectures for
  WLAN 3G integration toward 4G mobile data networks

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Note Abstract

• WLAN/3G interworking function
• INTERWORKING MODEL AND REQUIREMENTS
• NETWORK SELECTION
• INTERWORKING SCENARIOS
• 3G-Based Access Control and Charging
• REFERENCE POINTS
• Access to 3G Packet-Switched Services
• REFERENCE POINTS
• CONCLUSIONS

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WLAN/3G interworking function

• WLAN/3G interworking techniques and
  architectures can support
• Authentication
• Authorization
• Accounting
• WLAN sharing
• Consistent service provisioning

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INTERWORKING MODEL AND REQUIREMENTS (1)

• high-level WLAN/3G interworking model.

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INTERWORKING MODEL AND REQUIREMENTS (2)

• WLAN/3G interworking must
• provide 3G-based authentication
• support 802.1X access control
• support the legacy UAM and open access control
  schemes

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NETWORK SELECTION

• MS needs to perform the following selection
  procedures
• Select a WLAN that supports interworking with 3G
  PLMNs
• MS must select one of the PLMNs
• several solutions of network selection problem
• broadcast an SSID with a suitable format
• transmitting a probe request including a
  predefined well-known (3G-specific) SSID

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INTERWORKING SCENARIOS (1)

• Scenario 1 Common Billing and Customer Care
• Scenario 2 3G-Based Access Control and Charging
  
• Scenario 3 Access to 3G Packet-Switched
  Services
• Scenario 4 Access to 3G Packet-Switched-Based
  Services with Service Continuity
• Scenario 5 Access to 3G Packet-Switched-Based
  Services with Seamless Service Continuity
• Scenario 6 Access to 3G Circuit-Switched-Based
  Services with Seamless Mobility

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INTERWORKING SCENARIOS (1)
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3G-Based Access Control and Charging (1)

• INTERWORKING ARCHITECTURE

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3G-Based Access Control and Charging (2)

• AAA SIGNALING

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3G-Based Access Control and Charging (3)

• AAA SIGNALING
• MS sends its identity to the WLAN within an
  EAP-Response/Identity message
• MSs identity is NAI-1
• username_at_realm
• WLAN discovers route AAA messages to the 3G PLMN
  corresponding to this realm
• AAA access request is sent to the identified 3G
  PLMN over the Wr interface
• WLAN sends network advertisement data to the MS
  
• use a new EAP method called 3G-Info
• XML structure

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REFERENCE POINTS (1)

• 3G internal interfaces
• Wr/Wb
• carries AAA signaling between the WLAN and the 3G
  / home PLMN in a secure manner
• Support Radius by acrossWr/Wb
• Ws/Wc
• provides the same functionality as Wr/Wb but runs
  between a 3G AAA proxy and a 3G AAA server

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REFERENCE POINTS (2)

• Wf
• transport charging information toward the 3G
  operators CGw/CCF located in the visited or home
  PLMN
• Wo
• used by the 3G AAA server to communicate with the
  3G OCS

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REFERENCE POINTS (3)

• Wx
• between the 3G AAA server and the HSS
• used primarily for accessing the WLAN
  subscription profiles of the users
• D/Gr
• used for exchanging subscription information
  between the 3G AAA server and the HLR by means of
  the MAP protocol

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Access to 3G Packet-Switched Services (1)

• INTERWORKING ARCHITECTURE

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Access to 3G Packet-Switched Services (2)

• AAA SIGNALING

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Access to 3G Packet-Switched Services (3)

• AAA SIGNALING

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Access to 3G Packet-Switched Services (4)
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REFERENCE POINTS (1)

• several additional interfaces
• Wn
• used for transporting tunneled user data between
  the WLAN and the WAG
• Wm
• located between the 3G AAA server and PDG
• used to enable the 3G AAA server to retrieve
  tunneling attributes and an MSs IP configuration
  parameters from/via the PDG

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REFERENCE POINTS (2)

• Wi
• provided via the Wi interface based on IP
• Wg
• used by the 3G AAA proxy to deliver routing
  policy enforcement information to the WAG
• Wp
• transports tunneled user data traffic between the
  WAG and the PDG

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CONCLUSIONS

• maintain access to the same 3G packet-switched
  services across several radio access technologies
  
• such as IEEE 802.11, HiperLan/2, UTRAN, and
  GERAN
• Session mobility is an additional requirement
  that needs further consideration and presents
  considerable technical challenges

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Magazine 3

• IEEE802.11 roaming and authentication in wireless
  LAN cellular mobile networks

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Note Abstract

• Integrate wireless LAN service
• IEEE 802.11 WIRELESS LAN ROAMING
• RADIUS PROXY
• IEEE 802.11 HORIZONTAL ROAMING
• MOBILE IP HANDOFF PERFORMANCE IMPROVEMENT
• WIRELESS TRANSMISSION PRIVACY
• SECURITY ANALYSIS
• AUTHENTICATION AND KEY NEGOTIATION DEMONSTRATION
• SUMMARY

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Integrate wireless LAN service (1)
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Integrate wireless LAN service (2)

• IEEE802.11 service integration functionality
• integrate into cellular networks
• Wireless network security
• Service quality
• refers to handoff speed and packet loss rate

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Integrate wireless LAN service (3)
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IEEE 802.11 WIRELESS LAN ROAMING (1)

• IEEE802.11 roaming structure is based on
• AAA broker with a Remote Authentication Dial-In
  User Service (RADIUS) server proxy
• CA servers
• are special servers that issue and verify
  certificates to fixed nodes or networks upon
  request so that they have proofs to identify
  themselves
• are organized in a tree topology and working in a
  distributed way

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IEEE 802.11 WIRELESS LAN ROAMING (2)
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RADIUS PROXY

• RADIUS server retrieves
• remote servers domain from the users request
• includes the network access identifier
• identifier_at_domain_name

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IEEE 802.11 HORIZONTAL ROAMING (1)

• Each network domain is interconnected by AAABs
• In order to provide IP mobility
• foreign agent (FA) is placed into the NAS
• The architecture is able to process two
  horizontal roaming scenarios
• The current IEEE802.11 device connects to the
  network via the NAS
• Seamless roaming

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IEEE 802.11 HORIZONTAL ROAMING (2)
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IEEE 802.11 HORIZONTAL ROAMING (3)
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IEEE 802.11 HORIZONTAL ROAMING (4)
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MOBILE IP HANDOFF PERFORMANCE IMPROVEMENT (1)

• roam between a wireless LAN and a cellular
  network
• routed to the mobile station through its HA
• HA redirects the data flow to the new IP
  address
• For typical data applications is not necessary to
  use real-time seamless handoff
• For real-time Internet applications like voice
  or streaming video ,handoff latency and packet
  loss performance have become more and more
  critical

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MOBILE IP HANDOFF PERFORMANCE IMPROVEMENT (2)

• In order to reduce the latency of Mobile IP
  handoff
• used to assist Mobile IP handoff
• pre-registration and authentication data can be
  sent to the mobile station before it moves
• Additional flow control should be taken in the
  handover perio

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WIRELESS TRANSMISSION PRIVACY (1)

• built-in WEP encryption cannot guarantee data
  transmission privacy
• User location updates are transparent to the
  scheme since user mobility is handled in the
  network layer
• FA just relays the authentication message between
  the mobile station and its home network

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WIRELESS TRANSMISSION PRIVACY (2)

• Authenticating parties share a secret key
• stored in either the mobile station or its
  Subscriber Identity Module (SIM) card
• Authenticating parties do not share a secret key
• authentication between two mobile stations or a
  mobile station and a fixed Internet server
• Visit the Internet public resourc
• no authentication is needed

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WIRELESS TRANSMISSION PRIVACY (3)

• Authentication and key negotiation protocol
  between two mobile stations belonging

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WIRELESS TRANSMISSION PRIVACY (4)

• Scheme variation in various authentication
  scenarios

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SECURITY ANALYSIS (1)

• MS1 finds MS2s home address and creates a nonce
  with the corresponding hash value
• HA1 decrypts the message from MS1 HA1 realizes
  that MS1 intends to authenticate with a third
  party
• CA decrypts the message from HA1 and verifies
  IDHA1
• HA1 decrypts the message from CA, and gets the
  public key and device ID of HA2. HA1 stores the
  pubHA2 and IDHA2 pair
• HA2 will buffer the latter if the latter comes
• that must not be compromised

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SECURITY ANALYSIS (2)
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AUTHENTICATION AND KEY NEGOTIATION DEMONSTRATION

• demonstration uses RSA as the public key
  algorithm
• DES as the symmetric algorithm
• MD5 as one-way hash functions
• If the slowest network connection speed is 14.4
  kb/s in the cellular network with overhead of
  the transmission considered
• data transmission can be finished in less than 3
  s

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SUMMARY

• The proposed architecture offers a smooth
  transition of wireless LAN hot spots from
  non-roaming-supported to seamless-roam-ing-support
  ed
• A fast network switchover mechanism is available
  to improve the performance of streaming
  applications
• wireless transmission security is carefully
  considered

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Q A
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