Virtual Wire for Managing Virtual Dynamic Backbone in Wireless Ad Hoc Networks

Bo Ryu , Jason Erickson , Jim SmallcombACM MOBICOM 1999

OutlineIntroductionThe Concept Notation and Basic RulesManagement of VDB Backbone Selection Process (BSP) Backbone Connection Process (BCP) Backbone Maintenance Process (BMP)

Routing Unicasting Multicasting

Conclusion

IntroductionA novel distributed algorithm Employs the concept of virtual wire Its structure was called virtual dynamic backbone (VDB) reliable and scalable routing in wireless mobile ad hoc net

works The requirements Unicast routing Multicast routing QoS routing Low overhead Reliability Scalability

The Concept (1/6) Virtual Dynamic Backbone (VDB)

The Concept (2/6)

The advantages provided by VDB include:

The Concept (3/6)Virtual Wire Messages (VWMs)

The Concept (4/6)Virtual Wire Messages (VWMs)

Rate rExample:

Let r = 0.1 VWM/secNode 4 and 5 transmit VWMs rate is 8rVWMs size = 20 bytesBandwidth overhead = 128 bits/sec

20 x 8 x 8 x 0.1 = 128 bits/sec

The Concept (5/6)Virtual Handoff

6

The Concept (6/6)Virtual wire brings several key benefits:

Notation and Basic Rules(1/4)

Three types of nodes: Black => VDB node Green => at least one black node as its neighbor White => no black node as its neighbor

LQ ab link quality from node a to node b (v) The number of neighbors of node v

Each node generates Virtual Wire MessagesVirtual Attachment Point (VAP) Black or green has at least one Connect to VDB via VAP

Notation and Basic Rules(2/4)

A VWM contains the following fields:Source Node ID (S)Forwarding Node ID (F)VAP Link Quality Node ID (N)Link Quality Feedback (LQ)Hop Count (HC)Time-to-Live (TTL)Source Sequence NumberTransmitter Sequence NumberColor (c)Degree()

Notation and Basic Rules(3/4)

For example:

Notation and Basic Rules(4/4)

Management of VDB(1/3)Backbone Selection Process (BSP)

Backbone Selection Process (BSP)Backbone Connection Process (BCP)Backbone Maintenance Process (BMP)

Management of VDB(2/3)Backbone Connection Process (BCP)

Backbone Selection Process (BSP)Backbone Connection Process (BCP)Backbone Maintenance Process (BMP)

Management of VDB(3/3)Backbone Maintenance Process (BMP)

Backbone Selection Process (BSP)Backbone Connection Process (BCP)Backbone Maintenance Process (BMP)

Routing(1/8)Unicasting

Routing(2/8)Unicasting

Routing(3/8)Multicasting

Routing(4/8)Multicasting

Routing(5/8)Multicasting

Routing(6/8)Multicasting

Routing(7/8)Multicasting

Routing(8/8)Multicasting

ConclusionThis architecture is suitable for highly dynamic wireless ad hoc networks

The algorithm combines: virtual wire virtual dynamic backbone

The algorithm provides: Unicast routing Multicast routing

Future work Extensive simulation for evaluating its performance under

various topology Node mobility scenarios

The related issues

Overhead Routing sub-optimality Redundancy Scalability QoS support Asymmetric routing