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Seamless Handover in Terrestrial Radio Access Networks: A Case Study. 第 5 組 彭瑱瑞 李政穎 陳冠男 郝晉杰. Outline. Motivation Mobile IP Mobile IP in WLAN-GPRS environment Interworking between mIP and GPRS entities Simulation Conclusion. Motivation.
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Seamless Handover in Terrestrial Radio Access Networks:A Case Study 第5組 彭瑱瑞 李政穎 陳冠男 郝晉杰
Outline • Motivation • Mobile IP • Mobile IP in WLAN-GPRS environment • Interworking between mIP and GPRS entities • Simulation • Conclusion
Motivation • An ever-increasing traffic flows over wireless network • Existed wireless technology • WLAN, Bluetooth, GPRS, …. • Two of largest deployed packet-switch technology • 802.11 (WLANs) • High bandwidth, covers small areas • GPRS (WWANs) • Low bandwidth, covers large areas
Motivation (cont.) • Compare between various wireless technology
Motivation (cont.) • Roaming between GPRS/WLAN • Interface change • IP Address change • Upper layer application (TCP/UDP) disconnect • How to • Vertical Handovers with Mobile IP
Mobile IP • Component • MN • HA • FA • Operation • Agent Discovery • Registration • Tunneling
Vertical Handovers with mIP (cont.) • Vertical handover vs Mobile IP • Vertical handover • The mobile node registers its new location while it is still connected through its old access interface • Datagrams buffered into the old network that old interface can still reach • Very efficient in terms of datagram loss • Mobile IP • Handover occurs delay and data loss between different IP networks but over the same interface • Requires additional mechanisms to reduce delay and data loss
Target Usage Scenario • Foreign Agent • Help MN detect movement • Broadcast periodic advertisements and respond to solicitation message • Two scenarios • Foreign agent lend its IP address as CoA to MN • MN can detect movement through other means and acquire an IP address by itself • DHCP, PPP
Target Usage Scenario (cont.) • Another case • MH allocated in private IP address • Datagram traffic to and from the private CoA is transported over the Internet through IP-in-IP tunnels established between public endpoints
Interaction between MH and GPRS • Interaction between MH • Emulate laptop and GPRS handset as a PPP connection • To get IP address • PPP phase • LCP (Link Control Protocol) • PAP (Password Authentication Protocol) • IPCP (Internet Protocol Control Protocol) • Foreign agent discovery • Standard ICMP router discovery cannot be employed • Different protocol stack between IP Network and GPRS • long-haul message • Derives from standard ICMP message • Unicast message
Interaction between MH and GPRS TE MT GGSN Radius Server FA LCP negotiation PCP negotiation PDP context activation Radius authorization FA notification Long-haul unicast agent advertisement Mobile IP registration Interaction between the mobile node, foreign agent, and GGSN
Conclusion • Seamless communication in a heterogeneous networking environment • Mobile IP: ensure IP-level connectivity • Vertical handover: ability to use multiple access interfaces at one