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Link-layer Hints for Movement Detection. Alper Yegin IETF 57, Vienna July 18th, 2003. Detection and Reaction Cycle. Collect clues Link-layer hints Network-layer hints Make determination Change configuration Use some of the network-layer hints, learn others. Network-layer Can….
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Link-layer Hints for Movement Detection Alper Yegin IETF 57, Vienna July 18th, 2003
Detection and Reaction Cycle • Collect clues • Link-layer hints • Network-layer hints • Make determination • Change configuration • Use some of the network-layer hints, learn others
Network-layer Can… • Detect presence of a new router (or absence of an existing router) • Receive unsolicited router advertisements • Solicit advertisements • Detect presence or absence of a DHCP server • Unsolicited/solicited • Detect presence or absence of an “on-link” prefix • Observe traffic (promiscuous mode)
Link-layer Could… • Tell IP when link is torn down (link down) • Asynchronous notification • Tell IP when link is established (link up) • Asynchronous notification • Tell IP the link id when asked • E.g.: SSID with IEEE 802.11 • More fancy ones ….
Process • Passively collect hints • New prefixes advertised • Prefix goes stale • Prefix part of IP addresses change • Link up received • Actively collect hints • Send router advertisement • Learn the current link id • Make the determination
Notes • Who receives the L2 hints • Preferably host, but network-side (e.g., router) is useful too • Interpreting detection of a new link • Not necessarily means configuration change for network-layer • Security concerns
What Can We Do at IETF? • Define useful/practical link-layer hints • Details are link-layer specific, so use abstraction • www.yegin.org/alper/draft-manyfolks-l2-mobilereq-02.txt • Communicate with other SDOs • IEEE Handoff ECSG • “Summary of ongoing / proposed work in SEAMOBY, TRIGTRAN and IRTF's Micro Mobility initiative and requirements they might bring to the Handoff SG” • 3GPP/3GPP2 • Define two movement detection schemes • When L2 hints available • When L2 hints are NOT available (partial availability?) • Others?