A Mobility Gateway for SmallDevice Networks

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A Mobility Gateway for Small-Device Networks

• Robert Chalmers
• University of California, Santa Barbara
• robertc_at_cs.ucsb.edu
• Pervasive Computing 2004
• March 16, 2004

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Introduction

• small, connected devices are proliferating
• cell phones PDAs
• people expect ubiquitous connectivity
• voice is already here
• data is coming, on a small scale
• future devices will follow this trend
• appliances, sensors our environment

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Small Device Networks

• applications
• personal networks
• smart homes
• sensor networks
• keep them cheap
• limited processing and memory
• energy constrained
• new design constraints
• breaks end-to-end argument

twister net
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Degrees of Freedom

• protocol complexity
• addressing modalities
• mobility
• intelligence in the network
• topology
• route complexity
• bandwidth efficiency

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Degrees of Freedom

• protocol complexity
• addressing modalities
• mobility
• intelligence in the network
• topology
• route complexity
• bandwidth efficiency

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Protocol Complexity

• not all devices need the same network services

get loud.mp3
light is off
complex
simple
cheap
expensive
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Addressing Modalities

• 32 or 128-bit addressing may not be appropriate
• fewer bits to suit the application and population
  size
• apply semantics
• geographic/relative location
• attributes of source/destination
• tradeoffs
• gain optimization and flexibility
• lose inter-operability

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Mobility

• creates a distinction between
• who you are authentication, authorization,
  lookup
• where you are routing
• existing techniques
• host-based routing
• in routers per node state
• in packets increases packet overhead
• use two addresses
• a mapping must be maintained, but where?

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Mobility Mobile IP
128.111.52.30 ? 213.145.23.10
home agent 128.111.52.1
who 128.111.52.30
where 213.145.23.10
mobile node
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Mobility Mobile IP
128.111.52.30 ? 213.145.23.10
home agent 128.111.52.1
im cool. how you doin? moved to 213.145.23.10
who 128.111.52.30
where 213.145.23.10
128.111.52.30 ? 213.145.23.10
mobile node
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Mobility Mobile IP

• problems
• high signaling load
• long hand-off delays
• device complexity

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Intelligence in the Network

• interface between small-devices and Internet
• breaks the end-to-end argument
• reduces complexity of small devices
• conserve scarce resources power, bandwidth
• map between devices with different capabilities

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A Mobility Gateway
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A Mobility Gateway
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A Mobility Gateway
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Room for Improvement
Mipv6 overhead without security
Mipv6 overhead with security
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Impact
Power profile of a Dust Mote
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Degrees of Complexity

• dimensions are not independent
• optimizations are often tradeoffs
• no silver bullet
• integration is possible
• highly optimized small-devices
• IP-world of larger Internet
• must break the strict end-to-end philosophy

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Thank You
Robert Chalmers University of California, Santa
Barbara robertc_at_cs.ucsb.edu Pervasive Computing
2004 March 16, 2004