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Research Projects Hassan Peyravi |
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QoS provisioning in remote monitoring Using SNMP over TCP in multi-hop wireless and wired networks (with Iqbal Asif):
Remote monitoring solutions are prevalent in the financial industry to monitor Financial Transaction Devices (FTD's) such as an Automated Teller Machine (ATM) over highly congested or faulty networks. Fault detection of hardware devices on systems with a diverse software stack is required to be done remotely in a guaranteed delivery mechanism and in a timely fashion. Simple Network Management Protocol (SNMP) has been a standard and is widely used for such applications over UDP for fixed sized and a predefined payload. Such solutions create quality of service (QoS) issues with messages being lost during severe congestion and high network traffic. The message loss can result in, during busy times of the day, a FTD to be down at a remote location for hours. Due to non-receipt of status message by the remote monitoring application, a FTD may stay down for a much longer period than expected resulting financial losses. In this thesis, we propose a solution to this problem which is based on SNMP messaging over TCP. Due to the fact that TCP is congestion-sensitive and UDP is not, and MAC layer back-off algorithms exasperate the delay and loss differently in wired and wireless environment, we conducted a performance analysis of SNMP over several multihop wireless and wired networks. We studied the impact of load and number of hops on the performance of SNMP over TCP and UDP using delay, loss and throughput metrics.
Fault
tolerant routing in wireless mesh networks (with
Yasir Drabu):
Multi-hop Wireless mesh
networks (WMNs) are emerging as a viable alternative solution for
cost effective access networks. WMNs can fill the capacity and
coverage limitation of traditional cellular, point-to-point wireless
systems. In contrast to traditional cellular system, WMNs need only
one access point to the wired network, while other access points
share a connection over the air. Wireless mesh networks combine
several existing technologies and concepts from cellular, ad hoc,
and sensor networks to improve network coverage, easy of deployment
and better throughput. In this project, we propose and design a
fault-tolerant WMN based on a hexagonal
topology with multi-radio and directional
vectorized antennas. For this model, we introduce an addressing and
routing scheme that simplifies the network operations. Further, we
extend the routing approach to cope with one or multiple network
link failure, as link failure is common in wireless networks. To
address this, we exploit the regularity and multipath
characteristics of an augmented tri-sectionized hexagonal system to
route around link or node failures.
Y.
Drabu and H. Peyravi. Fault Tolerant Routing in Tri-Sector Wireless
Cellular Mesh Networks. In Proceedings Parallel and Distributed
Computer Systems (PDCS), pages 209-216, San Francisco, USA,
September 2006.
MAC
layer misbehavior in wireless networks (with
Jalaa Hoblos):
In wireless networks
such as IEEE 802.11, the nodes contend to access the medium through
a loosely distributed coordination via contention ( e.g., CSMA/CA) .
In these networks the access fairness is provisioned through a
uniform random access mechanism that is maintained by an exponential
or uniform back-off algorithm. However, nodes can easily gain more
access to the medium by manipulating their internal back-off
algorithm. A selfish node can reduce its contention window and gain
better throughput while other nodes can suffer from media access and
hence degradation in their throughput. This misbehavior cannot
easily be detected if the base station simply collects samples of
back of values. In fact a selfish node can reduces its contention
window in an statistical manner and in short run while maintaining
the statistical characteristics of its back-off values without being
detected in a long term. In this project, we are investigating
several statistical techniques to identify a selfish node.
Optimal
gateway placement in wireless mesh networks (with
Yasir Drabu):
The placement of
gateways in
wireless mesh networks has a critical impact on the overall
performance in terms of throughput and capacity. Finding optimal
locations through search space not only is computationally
intractable,but also infeasible due to the dynamic nature of the
traffic flows. In this project, we consider the problem of optimally
placing a given number of gateway routers in a wireless mesh with
the objective to minimize the transmission blocking probability. We
are investigating the performance of spacing the gateways
uniformly for an end-to-end performance with uniform loads that are
independently distributed across the network. Through simulation and
analysis, we are investigating the performance gains one
can achieve by different placement policies such as uniform
placement, random placement, and hot-spot placement for uniform and
non-uniform traffic models. For nonuniform link load, we
provide a dynamic programming algorithm for the optimal placement
and compare the performance with random and uniform placement.
We are also investigating the effect of different traffic models and
applications on the placement algorithms.
Y.
Drabu and H. Peyravi. Gateway placement with QoS constraints in
wireless mesh networks. In Proceedings
of the IEEE International Conference on Networking ,
pages 46–51, Cancun, Mexico, April 2008. IEEE Computer Society.
Dynamic
bandwidth management in IP networks (with
Yasir Y. Drabu):
While
a significant portion of Internet traffic is still best effort,
emerging applications with different quality of service(QoS)
requirements (e.g., multimedia) are evolving at a faster pace and
require more than best-effort services. The Integrated Services
(IntServ) model attempts to achieve an end-to-end per flow QoS
through RSVP, however it lacks scalability. The differentiated
services (DiffServ) model, on the other hand, attempts to classify
packets based on their QoS requirements to receive different
services, and it is the focus of recent IETF activity. To ensure
QoS, the admission control policy and the packet scheduler should
work in tandem to i) control the misbehaved traffic through
policing, shaping, metering, pricing techniques, and ii) contain the
delay, delay variation, packet loss rate, and bandwidth loss through
robust packet scheduling policies. In this project, we investigate
an adaptive admission control that reduces bandwidth loss when the
traffic is light and enforces a stringent traffic regulation when
the traffic load is high. A similar mechanism is used for the packet
scheduler that maintains the QoS metrics adaptively within their
limited boundaries. Internet2 traffic traces and Opnet synthetic
traffic are being used to evaluate the performance of the
algorithms.
Y.
Drabu and H. Peyravi. An adaptive bandwidth control algorithm for IP
routers. In Proceedings International Conference on Communications
in Computing (CIC), pages 311–317, Las Vegas, USA, June 2004.
Traffic
Management and QoS Provisioning in IP Networks (with
Yasir. Drabu):
The objective of this work is to investigate the
impact of self-similar traffic on the performance of output buffers
in switches and routers. It is a known fact that the superposition
of independent alternating renewal processes (flows) can show
self-similar characteristics. Since analytical and empirical studies
have shown that self-similar traffic can have a detrimental impact
on the QoS, finding an effective buffer management algorithm that
can manage self-similar traffic has become an important problem in
traffic engineering. Optimal resource allocation is directly
affected by optimal buffer size and buffer management policy,
bandwidth assignment and traffic management. In this project we
study the effect of self-similar and bursty traffic on the triggered
threshold buffer management algorithms. Besides the second-order
self-similar traffic, we are investigating the effects of fractional
Brownian motion on active queue management schemes.
Delay
and jitter analysis of Generalized TDMA with General Traffic (
with K. Khan):
The
TDMA (Time-Division Multiple Access) protocol with its variants has
been widely used and extensively researched in various wire-line and
wireless communication networks. Major medium access control (MAC)
protocols (e.g., random access, fixed and demand assignment
protocols), time slot interchange switches, and multiplexers are
based on TDMA. The next generation of wireless networks are expected
to support multimedia and real-time applications with quality of
service (QoS) guaranteed. The General Packet Radio Service (GPRS)
that allows continuous wireless connection to data networks is based
on TDMA is such an example. The GPRS technology allows mobile phones
to be used for sending and receiving data over an Internet Protocol
(IP)-based network.Most previously performance analyses of TDMA have
been based on the assumption of symmetric and predictable traffic
distributions. It has been assumed that either the message
inter-arrival time is exponentially distributed and/or the message
length is geometrically distributed. While these assumptions
provides analytical simplicity to estimate different performance
metrics of a communication channel, they may not realistically
reflect the behavior of modern traffic which are either correlated
and/or bursty in nature. In this research project, first we relax
the above assumptions and present a delay and jitter
performance analysis of a generalized TDMA for a general traffic.
Second, we present the analysis for two resource allocation
models, namely consecutive
and
interleaved
slot assignment
schemes within a frame time.
M.
K. Khan and H. Peyravi. Delay and jitter analysis of generalized
demand-assignment multiple access (DAMA) protocols with general
traffic. In HICSS ’05: Proceedings of the 38th Annual Hawaii
International Conference on System Sciences (HICSS’05) - Track 9,
page 304.1, Washington, DC, USA, January 2005. IEEE Computer
Society.