IEEE 802.11 DCF is the MAC protocol currently used in wireless LANs. 802.11
DCF is inefficient due to two types of overhead; channel idle time and
collision time. This paper presents the design and performance evaluation of an
efficient MAC protocol for wireless networks, called Token-DCF. Token-DCF
decreases both idle time and collision time. In Token-DCF, each station keeps
track of neighboring links' queue length by overhearing of transmitted packets
on the wireless medium. The result is then used to assign privileges to the
network stations.
In this paper, we explore the problem of iterative approximate Byzantine
consensus in arbitrary directed graphs. In particular, we prove a necessary and
sufficient condition for the existence of iterative byzantine consensus
algorithms. Additionally, we use our sufficient condition to examine whether
such algorithms exist for some specific graphs.
We consider the problem of maximizing the throughput of Byzantine consensus,
when communication links have finite capacity. Byzantine consensus is a
classical problem in distributed computing. In existing literature, the
communication links are implicitly assumed to have infinite capacity. The
problem changes significantly when the capacity of links is finite. We define
the throughput and capacity of consensus, and identify upper bound of
achievable consensus throughput.
In this report, building on the deterministic multi-valued one-to-many
Byzantine agreement (broadcast) algorithm in our recent technical report [2],
we introduce a deterministic multi-valued all-to-all Byzantine agreement
algorithm (consensus), with linear complexity per bit agreed upon. The
discussion in this note is not self-contained, and relies heavily on the
material in [2] - please refer to [2] for the necessary background.
Randomized algorithm that achieves multi-valued Byzantine agreement with high
probability, and achieves optimal complexity.
In this work we study the problem of misbehavior detection in wireless
networks. A commonly adopted approach is to utilize the broadcasting nature of
the wireless medium and have nodes monitor their neighborhood. We call such
nodes the Watchdogs. In this paper, we first show that even if a watchdog can
overhear all packet transmissions of a flow, any linear operation of the
overheard packets can not eliminate miss-detection and is inefficient in terms
of bandwidth. We propose a light-weigh misbehavior detection scheme which
integrates the idea of watchdogs and error detection coding.
In this work we study the problem of misbehavior detection in wireless
networks. A commonly adopted approach is to utilize the broadcasting nature of
the wireless medium and have nodes monitor their neighborhood. We call such
nodes the Watchdogs. In this paper, we first show that even if a watchdog can
overhear all packet transmissions of a flow, any linear operation of the
overheard packets can not eliminate miss-detection and is inefficient in terms
of bandwidth. We propose a light-weigh misbehavior detection scheme which
integrates the idea of watchdogs and error detection coding.