augmenting the backpressure collection protocol to support multiple sinks

Augmenting the Backpressure Collection Protocol to Support Multiple Sinks

Varun Shimoga Prakash, Dr. Omprakash GnawaliNetworked Systems Laboratory

Dept. of Computer ScienceUniversity of Houston

Problem Statement

• Enable the Backpressure Routing technique to route packets to multiple sinks within a network.

Expectations from the Solution

• Small Memory Overhead• Packet Delivery Performance• Adherence to conditions imposed by

Backpressure Routing.

Possible Solutions

• Virtualization of Queue Management• Clustering of Network• Feedback based model.

Virtualization of Queue Management

• Each node stores its local backpressure to each of the sink in the network.

• Single Queue of Packets• Backpressure values create a virtual queue for

each sink.• Backpressure values propagated through

beacons or snooping.

Source Node 3

Source Node 4

Source Node 1

Source Node 2

Sink Node 1 Sink Node 3

Sink Node 2

{Sink_1: Active}

1

4

3

2

{Sink_2: Active}

1

3

2

4

{Sink_1: 1Sink_2: 1} 4

3

2

{Sink_3: Active}

1

2

3

4

{Sink_3: 1}

1

2

3

{Sink_3: 2Sink_1: 2Sink_2: 2}

1

2

3

{Sink_3: 2Sink_1: 3Sink_2: 3}

1

2

3

Disadvantages

• More the number of sinks, larger the packet header and storage of local backpressure to sinks.

Possible Solutions

• Virtualization of Queue Management• Clustering of Network• Feedback based model.

Clustering of Network

• Create imaginary clusters in the network where sinks are the centroids.

• Controlled Broadcast until packets reach a node in the desired cluster of a sink.

The Network is clustered around eachSink. There is an affiliation of each of theNodes towards the cluster to which it belongs.

Source

Sink

Broadcast Message

Broadcast Message

This node has a gradient sloping towards the local sink. Route messagethrough Backpressure routing.

Disadvantages

• Controlled Broadcasting does not allow Linear Networks.

• Without controlled broadcasting, undesirable redundancy of messages increases.

Possible Solutions

• Virtualization of Queue Management• Clustering of Network• Feedback based model.

Feedback Based Model

• Sink sends feedback to the last node before it.• Feedback propagate to all nodes in network.• Based on feedback and past performance,

nodes choose their next hop.

Source Node 3

Source Node 4

Source Node 1

Source Node 2

Sink Node 1 Sink Node 3

Sink Node 2

Task: Send packets from Source Node 3 to Sink Node 1

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2

3

Initially Broadcastthe packet

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2

3

Broadcast

Broadcast

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2

3

Broadcast

Negative Feedback

1

2

3

Broadcast

Negative Feedback

Sink Node 1

Positive Feedback

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2

3

Sink Node 1

Positive Feedback

Sink 1:

1

2

3

Sink Node 1

Positive Feedback

Sink 1:

Sink 1:

1

2

3

Sink Node 1

Positive Feedback

Sink 1:

Sink 1:

Sink 2:

Sink Node 2

Sink 3:

Disadvantages

• Convergence of the entire network takes more time in case of mobile sinks.

• New weight parameter (feedback) to be considered to calculate weight.