Virtual ring routing Virtual ring routing Some slides from http:// - - PowerPoint PPT Presentation

Virtual ring routing Virtual ring routing

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Some slides from http://research.microsoft.com/en-us/um/people/antr/vrr- sigcomm06.ppt

VRR: the virtual ring VRR: the virtual ring

90E 910 FFF topology-independent node identifiers, e.g., MAC address

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8F6 90E 8F0 8E2 nodes organized into virtual ring by increasing identifier value each node maintains a virtual neighbor set (vset)

VRR: routing paths VRR: routing paths

8F6

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physical network topology 8F6

nodes only maintain paths to virtual neighbors:

• vset-paths are typically multi-hop
• vset-paths are maintained proactively

VRR: forwarding table VRR: forwarding table

endpointB pathId nextA nextB endpointA

10E 10 ME F42 31 8F6 90E 910 8F6 ME 14A 140 F42 10E 2 14A F42 8F6

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• vset-paths recorded in forwarding tables along path
• forwarding table contains
• vset-paths between node and vset members
• vset-paths between other nodes that go through node
• paths to physical neighbors

forwarding table for node 8F6 8F6 F42 ME F42 FF 140 10E

VRR: forwarding VRR: forwarding

• forward message destined to x by

– picking endpoint e numerically closest to x – forwarding message to next hop towards e

• deliver message to node with id closest to x

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• deliver message to node with id closest to x
• how does this work ?

– can find x because nodes are connected in a ring – low stretch because of additional forwarding state – many alternate paths to route around failures

VRR: example routing VRR: example routing

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physical network Topology

VRR: example routing VRR: example routing

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physical network Topology there may be some stretch

Node joining Node joining

broadcast hellos to find physical neighbors send setup request to 16E

130 Network Topology

19A 164 8F6 16E

send setup request to 16E (itself) through proxy (19A)

Node joining Node joining

164 sends setup to 16E with its vset 16E sends setup requests to nodes in received vset 16E adds node to vset

131 Network Topology

19A 164 8F6 16E 171

16E adds node to vset when it receives setup

Size of routing table Size of routing table

• Assume the nodes are randomly placed,

each vpath

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Simulation experiments in ns Simulation experiments in ns-2 2

• ran experiments with 802.11b MAC
• varied network size, mobility, session lifetime
• compared with DSDV, DSR, and AODV

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• VRR performed well in all experiments

– high delivery ratios even with fast movement – significantly lower delays with route instability

Delivery ratio: fast movement Delivery ratio: fast movement

60 70 80 90 100 ratio

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10 20 30 40 50 60 50 100 150 200 Number of nodes Delivery ra

DSDV DSR AODV VRR

Delay: fast movement Delay: fast movement

8 10 12 14 econds) DSDV DSR

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2 4 6 50 100 150 200 Number of nodes Delay (sec AODV VRR

Sensor network Sensor network

• sensor network testbed

– 67 mica2dot motes in UCB building

• comparison with BVR
• delivery ratio with mote failures

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• delivery ratio with mote failures

Sensor network: mote failures Sensor network: mote failures

100 110 120 130

• f nodes

92 94 96 98 100

ackets delivered

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50 60 70 80 90 0 1 2 3 4 5 6 7 8 9 101112131415

Time (mins) Number of

80 82 84 86 88 90

Number of nodes VRR delivery ratio BVR delivery ratio Percentage of pa

Wireless office testbed Wireless office testbed

• 30 machines running windows
• communicate using 802.11a
• throughput comparison with LQSR using ttcp

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Wireless office testbed: throughput Wireless office testbed: throughput

8 10 12 h (Mbps)

MR-LQSR VRR

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2 4 6 Machine Bandwidth

Why a virtual ring? Why a virtual ring?

• Alternatively, use an Euler tour to define coordinates on

the sensor nodes.

– An Euler tour is a cycle that visits every vertex. – Can be constructed by a depth-first tour on a spanning tree. – Also use shortcuts for greedy routing.

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