1. doc.: IEEE 802.11-03/827r0 Submission November 2003 Eleanor Hepworth, Siemens Roke ManorSlide 1 Co-existence of Different Authentication Models Eleanor Hepworth, Siemens Roke Manor eleanor.hepworth@roke.co.uk

2. doc.: IEEE 802.11-03/827r0 Submission November 2003 Eleanor Hepworth, Siemens Roke ManorSlide 2 Issues for Co-existence Multiple ways to support authentication for Public Access WLAN access Operator requirement for a smooth migration path / way to support both (co-existence) Need some enhanced features in the hotspot e.g. capability advertisement –802.11 flexibility allows this to be supported in multiple ways –interoperability problems? (analogous to those encountered for Virtual APs)

3. doc.: IEEE 802.11-03/827r0 Submission November 2003 Eleanor Hepworth, Siemens Roke ManorSlide 3 Authentication Models Two basic models for PWLAN –UAM: defined by WiFi Alliance –802.11i: defined by IEEE UAM is widely implemented in existing hotspots –Question now facing operators is whether and how to move towards 802.11i without annoying subscribers

4. doc.: IEEE 802.11-03/827r0 Submission November 2003 Eleanor Hepworth, Siemens Roke ManorSlide 4 Operator Goals Common user experience Support for as many subscribers as possible (including roamed users) Stepwise introduction of new components (avoid all or nothing upgrades) Reuse of existing infrastructure where possible Therefore, one option is to allow solutions to co-exist in the same network

5. doc.: IEEE 802.11-03/827r0 Submission November 2003 Eleanor Hepworth, Siemens Roke ManorSlide 5 Hotspot Requirements To support this, hotspot needs to provide –Operator Advertisement –Capability Advertisement e.g. data rate/QoS, authentication model, cost Possible solution in virtual APs –SSID provides clue as to capabilities of the virtual AP/access network

6. doc.: IEEE 802.11-03/827r0 Submission November 2003 Eleanor Hepworth, Siemens Roke ManorSlide 6 Operator Advertisement Can be implemented in two ways 1.The hotspot operator advertises their own identity but provides roamed information via some other mechanism e.g. EAP I-D in IETF – requires support in APs. 2.Each roamed operator advertises their association with the hotspot via SSIDs in beacons and probe responses (i.e. multiple operators share the same hotspot infrastructure) Information needs to be “meaningful”, especially for option 2 (SSIDs are not local anymore) –we need a standard naming convention, who is responsible for defining this?

7. doc.: IEEE 802.11-03/827r0 Submission November 2003 Eleanor Hepworth, Siemens Roke ManorSlide 7 Capability Advertisement May wish augment SSID with additional information –SSID is currently unstructured –A structure is needed, who defines this? (Need a consistent way for a driver to interpret what information is being provided by the SSID)

8. doc.: IEEE 802.11-03/827r0 Submission November 2003 Eleanor Hepworth, Siemens Roke ManorSlide 8 Virtual APs Do Virtual APs provide the solution for all PWLAN requirements? Scenario: if 5 operators are sharing a hotspot, each wanting to advertise UAM and WPA access, this leads to 10 VAPs per AP –There are scalability and administrative overhead concerns

9. doc.: IEEE 802.11-03/827r0 Submission November 2003 Eleanor Hepworth, Siemens Roke ManorSlide 9 Conclusions No clear impacts on 802.11 standard –BUT, there are interoperability issues Many different external standardisation bodies are investigating the use of SSIDs for operator/capability advertisement –Who should provide guidance on these aspects? Need to verify that Virtual APs provide the necessary support –Who is responsible for this?