Network Modelling Meeting - June 27

[Joseph Peters <peters@cs.sfu.ca>]

NETWORK MODELLING RESEARCH GROUP
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Friday, June 27, 13:30, ASB 9896

Speaker:  Meihua Judy Zhan
         School of Computing Science

Title:    Reliable Multicast Extension to IEEE 802.11 in Ad Hoc Networks

Juice and cookies will be provided.
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Abstract:

The IEEE 802.11 standard uses channel reservation schemes and acknowledgements
(ACKs) to provide reliable Medium Access Control (MAC) layer unicast services.
In contrast, 802.11 does not guarantee the reliability of MAC layer
broadcast/multicast transmissions.  This lack of reliability extends to ad hoc
routing protocols, such as DSR and AODV, which depend on broadcast packets to
exchange routing information among nodes.  In this talk, I will introduce an
efficient and reliable MAC layer multicast/broadcast protocol called SAM
(Sequential Acknowledgement Multicast protocol) and show simulations that compare
its efficiency and reliability to other broadcast/multicast protocols.  The basic
idea of SAM is that the multicast receivers send back Clear to Send (CTS) and
ACK frames in a predefined order to avoid collisions at the transmitter.  During
the retransmission phases of the protocol, the sender only needs to retransmit
to nodes that failed to send an ACK back. This alleviates the exposed terminal
problem in multi-hop ad hoc networks.  SAM is efficient, reliable, and easy to
implement. Most importantly, it is compatible with the IEEE 802.11 standard.