FLIP: a Flexible Protocol for Efficient Communication Between Heterogeneous Devices

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FLIPa Flexible Protocol for Efficient
Communication Between Heterogeneous Devices
Ignacio Solis, Katia Obraczka and Julio
Marcos Information Sciences Institute, University
of Southern California The authors have
since moved. Solis and Obraczka are now
affiliated with the University of California,
Santa Cruz.
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Talk overview

• FLIP overview
• Why FLIP? Motivation
• FLIP headers
• FLIP packets
• Comparison with IP
• Comparison with Diffusion
• Conclusions
• Future Work

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What is FLIP?

• FLIP is a network protocol that aims to be
  flexible. It tries to reduce the overhead as much
  as possible for small devices but does not limit
  the functionality of more powerful ones.
• Configurable by higher layers (Header morphing)

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Why FLIP?

• Generic protocols have too much overhead for
  small devices.
• Specific protocols are not general enough.
• Applications need access to the lower layers to
  optimize use.
• Every bit counts

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Sensor Networks

• Data gathering
• Small power constrained devices
• Wireless communication
• Long Lifetime
• Large Scale
• Specific Tasks
• Unattended

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What about IP?

• Overhead
• Addressing scheme?
• Routing?
• Fragmentation?
• Size?
• etc.

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Fields defined by FLIP

• Version (1 byte)
• Destination (2, 4 or 16 bytes)
• Source (2, 4 or 16 bytes)
• Length (2 bytes)
• Time To Live (1 byte)
• Flow (4 bytes)
• Protocol (1 byte)
• Checksum (2 bytes)

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The Meta-Header Bitmap

• The meta-header bit map defines which fields will
  be included in the header.
• Each header field will be represented by one or
  more bits in the meta-header.
• If the bit is on, the field will appear.

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The continuation bit

• We don't really need the whole meta-header bitmap
  since not all fields might be required.
• The bitmap is divided in groups which are then
  placed on different bytes.

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The ESP packet

• Extra-Small-Packet
• For special very small payloads (6 or 14 bits)

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FLIP's Meta Header
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Sample FLIP packet
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Sample API

• Uses standard socket interface

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Comparison with IP
Packet sizes for 1 and 1000 byte payloads
The special cases of Destination and Source and
Destination only use 2 byte addresses.
Percentages are overhead of header compared to
data.
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Comparison with Diffusion
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Conclusions

• FLIP incurs in small overhead when providing IP
  functionality.
• Header overhead on special cases can be very
  small. For example on very small payloads.
• It does not try to replace protocols such as IP.
• More research is needed since many variables are
  yet to be determined.

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Future Work

• Design of the other components.(Transport,
  routing, etc.)
• MAC layer integration/awareness.
• Header field ordering.
• Scenario simulations with FLIP enabled/disabled
  protocols.
• Real world differences.
• Is it worth it?

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Thank You
http//www.cse.ucsc.edu/isolis/flip
Ignacio Solis isolis_at_cse.ucsc.edu Katia
Obraczka katia_at_cse.ucsc.edu Julio Marcos
julio_at_donjulio.net