1. Implementation and Evaluation of a Performance Enhancing Proxy for Wireless TCP Scenarios and Architecture

2. Scenarios of interest Definition Scenario: Every time, hardware changes (including configurations) have to be done, a new scenario is created.

3. Meta-Modell for Scenarios ??????

4. Classification Classify Scenarios in different Classes: Wired Wireless –Local (fixed IP) –Mobile Handover Access Points Handover Access Techniques

5. Standard Wired Scenarios Possible Scenarios: Server & Client in same net (LAN), client-server- path known and traffic „stable/static“ Wired World = Internet, Client & Server in different subnets, path unknown, traffic variable, more congestion Client Server (e.g. HTTP, FTP) ”Wired World”

6. Fixed wireless Scenario Possible Scenarios: Server in same/different subnet as Client High BER Signal loss, reconnect Wired World WLAN AP Server (e.g. HTTP, FTP)

7. Mobile Wireless Scenario (Access Points) Possible Scenarios: AP‘s same/different subnet Server & Client same/different subnet Wired World WLAN AP Server (e.g. HTTP, FTP) WLAN AP Handover

8. Mobile Wireless Scenarios (Access Techniques) Possible Scenarios: WLAN -> GPRS -> WLAN WLAN -> UMTS -> WLAN WLAN -> Bluetooth -> WLAN..... Wired World WLAN AP Server (e.g. HTTP, FTP) GPRS AP Handover

9. Current Network Architecture

10. IP LAB: Current Architecture E A B C D Internet GPRS Network Server (e.g. Video application) WLAN (802.11) Wired access (Ethernet) Cellular access (GPRS) Router Switch WLAN AP Router

11. Meta-modell for Network Architectures

12. Meta-Network-Modell TCP Proxy Server (e.g. HTTP, FTP) ”Wireless World” ”Wired World”

13. Possible Network Architectures

14. Classification of Architectures Intercepting –In-Path –Router-Config –Gartious ARP Forced (Terminologie??) –IP-Tunneling –IP-Header-Modification

15. Full Intercepting Proxy Network Design Internet GPRS Network Server (e.g. HTTP, FTP) Cellular access (GPRS) A Router Switch WLAN AP 1 WLAN AP 3 B Router D E C TCP Proxy Intranet StudNet Terminal WLAN AP 2 Client Switch WLAN AP 4 TCP Proxy Wireless World Wired World

16. Possible Scenarios in Full Intercepting Server -> Switch -> Client Server -> Switch -> TCP Proxy -> WLAN AP 3-> Client Server -> Switch -> Routers -> Switch -> TCP Proxy -> WLAN AP 1 -> Client Server -> Switch -> Routers -> TCP Proxy -> Internet -> Intranet -> Terminal Handover WLAN AP 1 -> WLAN AP 2 Handover WLAN AP 2 -> WLAN AP 3 Handover WLAN AP 3 -> WLAN AP 4 Handover WLAN AP -> GPRS

17. Problems of Full Intercepted Proxy Scenario Hardware efforts (4 Proxies) -> reduction to max. 2 proxy PC‘s for handover possible => reconfig for every Scenario needed Internal Server access by Port-Forwarding How to realize GPRS handover (Server IP change from internal to external IP needed, use Mobile IP??)

18. Improved Intercepting Proxy Network Design Internet Server (e.g. HTTP, FTP) GPRS Network Cellular access (GPRS) A Router Switch WLAN AP 1 WLAN AP 3 B Router D E C TCP Proxy Intranet StudNet Terminal WLAN AP 2 Client Switch WLAN AP 4 Switch Wireless World Wired World IMPOSSIBLE

19. Forced Proxy Scenarios Internet GPRS Network Server (e.g. HTTP, FTP) A Router Switch WLAN AP 1 WLAN AP 3 B Router D E C Intranet StudNet Terminal WLAN AP 2 Client Switch WLAN AP 4 TCP Proxy Wireless World Wired World

20. Problems of Forced Proxy Solution How to implement forced Proxy? Possible Solutions: –„TCP packet in TCP packet“-solution (IP- Tunneling) –Modifying TCP packet: Target IP in Optional field, Proxy IP in Dest. Field How to access internal Proxy from outside world (New TCP Proxy protocol on new port + port forwarding)? More network traffic, evtl. More hops GPRS problem not resolved (MobileIP)

21. Router Config Proxy Scenarios Internet GPRS Network Server (e.g. HTTP, FTP) Cellular access (GPRS) A Router Switch WLAN AP 1 WLAN AP 3 B Router D E C Intranet StudNet Terminal WLAN AP 2 Client Switch WLAN AP 4 TCP Proxy Wired World Mixed World Wireless World Mixed World

22. Automated Forced Proxy Network Design Idea: –Categorize every port on router in „wireless, wired, (evtl. Mixed?)“ –Force router to send packets from wireless to wired over TCP Proxy ( send from Mixed or to Mixed always over TCP proxy) Problems: –Is this possible? –How to force WLAN AP 3 & 4 to use Proxy?

23. Functional Architecture „Implementation Plan“

24. Functional Implementation Router Config ARP to catch all packets Internet GPRS Network Server (e.g. HTTP, FTP) Cellular access (GPRS) WLAN AP 3 D Router E Intranet StudNet Terminal Client Switch WLAN AP 4 TCP Proxy