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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 • During handoff process (e.g., authentication), a temporary access is necessary. • During the temporary access, the authentication (e.g., 802.1x) and the creation of encryption key (e.g., PTK) will be handled. Fujio Watanabe, DoCoMo USA Labs

  7. Temporary Access during Handoff • AAAF is responsible of the temporary access and distribution of a handoff key. AAAH HO Key AAAF PTK per STA 802.1x Handoff AP2 AP1 HO Key HO Key Filtering HO-Key Response HO-Key Request HO Key Fujio Watanabe, DoCoMo USA Labs

  8. Merit of Handoff Key • The performance of pre-authentication using the handoff key (HO-Key) does not depend on mobility prediction. • The HO-Key minimize a disruption time of real time application during handoff. • The HO-Key is periodically changed. • The HO-Key supports a fast handoff. Fujio Watanabe, DoCoMo USA Labs

  9. Additional Changes • HO-Key Request Message from STA • HO-Key Response Message to STA • Distribution of HO-Key (encrypted by a current PTK) and inform a periodic cycle of HO-Key rekeying, temporary access expired time • Distribution of HO-Key between AAAF and APs (e.g., IETF) Fujio Watanabe, DoCoMo USA Labs

  10. 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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