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FLIP:Flexible Interconnection Protocol
Ignacio SolisKatia Obraczka
Talk overview
● FLIP overview● Why FLIP? Motivation● FLIP headers● FLIP packets● Comparison with IP● Comparison with Diffusion● Conclusions
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)
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
Sensor Networks
● Data gathering● Small power constrained devices● Wireless communication● Long Lifetime● Large Scale● Specific Tasks● Unattended
What about IP?
● Overhead● Addressing scheme?● Routing?● Fragmentation?● Size?● etc.
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)
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.
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.
The ESP packet
● Extra-Small-Packet● For special very small payloads (6 or 14 bits)
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Current Work on FLIP
FLIP Header GTP Header
GTP flags
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Sample FLIP Packets
FLIP ESP packet(extra simple packet)
FLIP/GTP packet
Sample API
● Uses standard socket interface
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FLIP Functions
Comparison with IP
The special cases of Destination and Source and Destination only use 2 byte addresses. Percentages are overhead of header compared to data.
Packet sizes for 1 and 1000 byte payloads
09
/26
/19
02
09
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02
09
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02
09
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02
09
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02
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02
01/19/1900
01/20/1900
02/08/1900
02/11/1900
01/09/1900
01/02/1900
0%
2500%
5000%
7500%
10000%
50% 50% 50% 50% 50% 50%
1000 byte payload Header Overhead
IPv4 FLIP (IPv4) IPv6 FLIP (IPv6) FLIP (D+S) FLIP (D)IPv4 FLIP (IPv4) IPv6 FLIP (IPv6) FLIP (D+S) FLIP (D)
12/3
1/18
99
12/3
1/18
99
12/3
1/18
99
12/3
1/18
99
12/3
1/18
99
12/3
1/18
99
01/19/1900
01/20/1900
02/08/1900
02/11/1900
01/09/1900
01/02/1900
0%
2500%
5000%
7500%
10000%
50% 50% 50% 50% 50% 50%50% 50% 50% 50% 50% 50%
1 byte payload Header Overhead
IPv4 FLIP (IPv4) IPv6 FLIP (IPv6) FLIP (D+S) FLIP (D)IPv4 FLIP (IPv4) IPv6 FLIP (IPv6) FLIP (D+S) FLIP (D)
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Directed Diffusion● Sink node collects data● Sink floods an interest to the whole network, establishing
reverse paths to itself.● Nodes that have the data the sink is interested in report
back (multiple-paths).● Sink reinforces the best path, that is, requests a higher
data rate on that path.● The interest is flooded periodically● Newer versions of Directed Diffusion have other
mechanisms
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Scenario 1: Diffusion Packets
Diffusion Static Header
Flexible HeaderCan we optimize Diffusion
by using FLIP?
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Diffusion Monitoring
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Scenario 2: Simple Data Gathering
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Simulation Parameters
● NS-2, 2000m x 2000m area, 10 runs, 21 secs.● 300 nodes, no movement.● 250m transmission range.● 802.11-like MAC. 660 mW / 395 mW● Starting energy is 1 Joule● Interests are every 5 seconds● 1 source, 1 sink requesting 10pkts/sec
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Simple Data Gathering
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Adding Data Aggregation
● Aggregate data as it flows through the network● Data must meet certain criteria● Not all data can be aggregated● Lossy & lossless aggregation
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Scenario 3: Ring Aggregation
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.
