1. presented by Hasan SÖZER1 PUBLIC ACCESS MOBILITY LAN: EXTENDING THE WIRELESS INTERNET INTO THE LAN ENVIRONMENT JUN LI STEPHEN B.WEINSTEIN JUNBIAO ZHANG NAN TU NEC USA INC.

2. presented by Hasan SÖZER2 Outline Introduction PamLAN Architecture & Protocol Components Security Issues Mobility Management Conclusion

3. presented by Hasan SÖZER3 Introduction Aim is to meet Ubiquitous access High data rate Local services Need for Wireless LAN environments

4. presented by Hasan SÖZER4 Introduction (cont’d) Architectural guidelines for WLAN environments Large-scale IP-based Supporting mobile/portable appliances

5. presented by Hasan SÖZER5 Introduction (cont’d) IP-level service Independence from wireless medium access technology Multi-segment LAN Supporting handoffs Based on wired LAN environment Wireless access points are imbeded

6. presented by Hasan SÖZER6 Introduction (cont’d) Recent developments in Cellular systems Wireless LAN technologies Most WLANs are Either private (i.e. For companies) Or available through subscription

7. presented by Hasan SÖZER7 PamLAN IP-based Public Access Mobility LAN Supports Internet Access via WLANs Multiple air interfaces Multiple virtual operators Location dependent services Local IP mobility QoS (within wired network)

8. presented by Hasan SÖZER8 PamLAN Stakeholders: Network operators Hotel, airport,... Third-party service providers (like ISPs) Franchises obtained from PamLAN operator Also called: virtual operators End users

9. presented by Hasan SÖZER9 PamLAN May have multiple LAN segments Airports, hotels, universities,... Can be built on existing LANs By adding wireless access points

10. presented by Hasan SÖZER10 PamLAN vs. Cellular Systems Even 3G mobile communication systems would not be sufficient for evolving Internet applications 384 kb/s outdoors, 2 Mb/s indoors downstream burst rates Intrinsic problem: providing continuous coverage in reserved spectrum Investment/Capacity scalability???

11. presented by Hasan SÖZER11 PamLAN vs. Cellular Systems WLANs have free spectrum Problem: Potential interfarence i.e. IEEE 802.11b & Bluetooth Property owners may be agreed or enforced on compatibility

12. presented by Hasan SÖZER12 Promises of PamLAN Addresses problems in current WLANs Lack of public access Being tied down to a single access point Single air interface Not a breakthrough in technological capacities Combination of available technologies

13. presented by Hasan SÖZER13 PamLAN : Usage of WLAN WLANs Has cost/performance advantages when compared with cellular mobile systems Likely to be the prefered technology in future for Internet appliance communication sessions

14. presented by Hasan SÖZER14 Architecture PamLAN/VOLAN/VLAN hierarchy PamLAN: multiple virtual operators VOLAN: Virtual Operator LAN Extends VLAN capabilities across subnetworks VLAN: Virtual LAN Implements user group feaures Simulates a physical LAN on a multisegment LAN environment

15. presented by Hasan SÖZER15 Architecture (cont’d) Switched Ethernet LAN Access Points Supporting IEEE, Bluetooth, Cellular,... IP-based access router with proxies Gateway routers Internet access through IP-tunneling

16. presented by Hasan SÖZER16 Architecture (cont’d)

17. presented by Hasan SÖZER17 Architecture (cont’d) QoS is supported by Ethernet Switches CSMA/CD + full duplex (no contention) Integration of Cellular IP & Mobile IP for supporting mobility MPLS (Multi-Protocol Label Switching) Brings QoS across multiple LAN segments

18. presented by Hasan SÖZER18 Related Protocols & Standards IEEE VLAN standard 802.1Q 12 bit VLAN ID imbedded within 4 byte section of Ethernet header determines membership IEEE 802.1p header for QoS 3 bit section in IEEE 802.1Q header that differentiate 8 frame priorities

19. presented by Hasan SÖZER19 Large Scale PamLAN For single VLAN QoS can be easily supported For large scale WLANs? Intermediate routers work at layer 3 Layer 2 information is lost Source & destination addresses must be used for VOLAN membership Intermediate routers must know all IP addresses for VLAN mapping

20. presented by Hasan SÖZER20 Large Scale PamLAN (cont’d) Solution: MPLS Simple & efficient Access points & Internet gateways handle VOLAN provisioning Intermediate routers are shielded from details VLAN for grouping traffic per VOLAN MPLS for whole PamLAN

21. presented by Hasan SÖZER21 MPLS (Multi-Protocol Label Switching) Tunnels traffic between gateways & access points Intermediate routers only examine MPLS labels, which imposes a path Forwarding Equivalence Class (FEC) Formed based on VOLAN membership & QoS FEC is inserted in MPLS label Used for 802.1p priority within VLAN

22. presented by Hasan SÖZER22 MPLS (cont’d)

23. presented by Hasan SÖZER23 MPLS (cont’d) Traffic engineered paths can be set up among access points and Internet gateways according to service contracts between PamLan & virtual operators

24. presented by Hasan SÖZER24 Protocol Stack

25. presented by Hasan SÖZER25 Security Issues Mutual Authentication Secure Channel Establishement Authorization Filtering at the access point

26. presented by Hasan SÖZER26 Mutual Authentication RADIUS (Remote Authentication Dial-In User Service) IP-based authentication (~802.11 proposal) 5 Basic Steps: Obtaining IP (DHCP) Login session access point: relay agent to virtual operator Challenge-responce protocol for authentication PKC for securing channel

27. presented by Hasan SÖZER27 Mutual Authentication (cont’d)

28. presented by Hasan SÖZER28 Securing Channel After authentication User’s profile is transfered to the access point including his/her public key Access point sends session key encrypted under the corresponding public key IPSEC together with ESP can be used for security at IP layer depending on user requests

29. presented by Hasan SÖZER29 Authorization Control Based on user credentials, packets can be filtered at the access point

30. presented by Hasan SÖZER30 Accounting 3 possible charging policies Flat-fee based Per-session Usage based Avoidance dispute by digital signature

31. presented by Hasan SÖZER31 Mobility Issues Mobility should be supported at layer 3 Multiple subnetworks within PamLAN Micromobility Roaming within PamLAN

32. presented by Hasan SÖZER32 Mobility Issues (cont’d) Possible approaches Cellular IP: refreshing router contents can be a burden for too many users MPLS based: only end points have to update location Old, new access points and Internet gateway need to be informed

33. presented by Hasan SÖZER33 Mobility Issues (cont’d) Fast handoff No repetative authentication Move user profile from old access point to the new one Access point re-establishes connection with virtual operator Access point sends old session key and new session key encrypted under user’s public key

34. presented by Hasan SÖZER34 Conclusion Sequre Extensible Multiple services Multiple air interfaces ? Are all appliances capable of handling PKC opreations