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Connectivity Problems

Connectivity Problems. Fujio Watanabe, Alex Hagen, Gang Wu DoCoMo USA Labs fwatanabe@ieee.org. Background. Hotspot » Continuous Coverage Seamless connectivity is required for multimedia applications. VoIP end-end delay <250-300ms VoIP Jitter <80ms VoIP has 050-xxxx-xxxx numbering.

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Connectivity Problems

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  1. Connectivity Problems Fujio Watanabe, Alex Hagen, Gang Wu DoCoMo USA Labs fwatanabe@ieee.org Fujio Watanabe, DoCoMo USA Labs

  2. Background • Hotspot » Continuous Coverage • Seamless connectivity is required for multimedia applications. • VoIP end-end delay <250-300ms • VoIP Jitter <80ms • VoIP has 050-xxxx-xxxx numbering Fujio Watanabe, DoCoMo USA Labs

  3. Introduction • This presentation raises a problem of the time required for authentication while the STA moves from one AP to another. • In providing the VoIP service over WLAN, the most viable concern is the amount of disruption time to process the handoff of an ongoing VoIP call (or session). Fujio Watanabe, DoCoMo USA Labs

  4. Problems (1/2) • Disruption of real time applications • At least 15 messages are required whenever the STA changes AP. • Long authentication & authorization time may take a few seconds (RADIUS based AAA: 4 local loop traversals). • Prediction (not related security) • Mobility prediction may be incorrect. (Seamoby, IETF) • Pre-authentication proposed will help but needs exact prediction information and may not be efficient. Fujio Watanabe, DoCoMo USA Labs

  5. Problem (2/2) 11-02-758r1-F-fast-handoff.ppt • Pre-authentication will have difficulty in highly mobile situations. • Pre-authentication will have difficulty when coverage overlap is small. • Pre-authentication is significantly more complex. • Pre-authentication derives a new security context per AP. Fujio Watanabe, DoCoMo USA Labs

  6. Approaches • Real-time applications need to have an immediate access to the new AP in case of handoff. • During handoff process (e.g., authentication), a temporary access is necessary. • Collaboration with IETF Fujio Watanabe, DoCoMo USA Labs

  7. Example of Temporary Access during Handoff • Data frame before authentication is encrypted by a handoff key. • A handoff key is a symmetric or an asymmetric key. HO-key HO-key Handoff PTK per STA 802.1x Filtering MAC Fujio Watanabe, DoCoMo USA Labs

  8. Conclusion • Need to improve the pre-authentication method to minimize the disconnection time during handoff. • An alternative approach is to develop a new method to transmit data frames during handoff. Fujio Watanabe, DoCoMo USA Labs

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