Use some of the network-layer hints, learn others

1
Link-layer Hints for Movement Detection

• Alper Yegin
• IETF 57, Vienna
• July 18th, 2003

2
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

3
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)

4
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 .

5
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

6
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

7
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-0
  2.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?