Abstract: A synchronous network-on-chip using wormhole packet switching
and supporting guaranteed-completion best-effort with low-priority (LP)
and high-priority (HP) wormhole packet delivery service is presented in
this paper. Both our proposed LP and HP message services deliver a good
quality of service in term of lossless packet completion and in-order message
data delivery. However, the LP message service does not guarantee minimal
completion bound. The HP packets will absolutely use 100% bandwidth of
their reserved links if the HP packets are injected from the source node with
maximum injection. Hence, the service are suitable for small size messages
(less than hundred bytes). Otherwise the other HP and LP messages, which
require also the links, will experience relatively high latency depending on the
size of the HP message. The LP packets are routed using a minimal adaptive
routing, while the HP packets are routed using a non-minimal adaptive routing
algorithm. Therefore, an additional 3-bit field, identifying the packet type,
is introduced in their packet headers to classify and to determine the type
of service committed to the packet. Our NoC prototypes have been also
synthesized using a 180-nm CMOS standard-cell technology to evaluate the
cost of implementing the combination of both services.
Abstract: In this paper a special kind of buffer management policy is studied where the packet are preempted even when sufficient space is available in the buffer for incoming packets. This is done to congestion for future incoming packets to improve QoS for certain type of packets. This type of study has been done in past for ATM type of scenario. We extend the same for heterogeneous traffic where data rate and size of the packets are very versatile in nature. Typical example of this scenario is the buffer management in Differentiated Service Router. There are two aspects that are of interest. First is the packet size: whether all packets have same or different sizes. Second aspect is the value or space priority of the packets, do all packets have the same space priority or different packets have different space priorities. We present two types of policies to achieve QoS goals for packets with different priorities: the push out scheme and the expelling scheme. For this work the scenario of packets of variable length is considered with two space priorities and main goal is to minimize the total weighted packet loss. Simulation and analytical studies show that, expelling policies can outperform the push out policies when it comes to offering variable QoS for packets of two different priorities and expelling policies also help improve the amount of admissible load. Some other comparisons of push out and expelling policies are also presented using simulations.
Abstract: Recently, Denial of Service(DoS) attacks and Distributed DoS(DDoS) attacks which are stronger form of DoS attacks from plural hosts have become security threats on the Internet. It is important to identify the attack source and to block attack traffic as one of the measures against these attacks. In general, it is difficult to identify them because information about the attack source is falsified. Therefore a method of identifying the attack source by tracing the route of the attack traffic is necessary. A traceback method which uses traffic patterns, using changes in the number of packets over time as criteria for the attack traceback has been proposed. The traceback method using the traffic patterns can trace the attack by matching the shapes of input traffic patterns and the shape of output traffic pattern observed at a network branch point such as a router. The traffic pattern is a shapes of traffic and unfalsifiable information. The proposed trace methods proposed till date cannot obtain enough tracing accuracy, because they directly use traffic patterns which are influenced by non-attack traffics. In this paper, a new traffic pattern matching method using Independent Component Analysis(ICA) is proposed.
Abstract: This paper presents results of measurements campaign
carried out at a carrier frequency of 24GHz with the help of TPLINK
router in indoor line-of-sight (LOS) scenarios. Firstly, the
radio wave propagation strategies are analyzed in some rooms with
router of point to point Ad hoc network. Then floor attenuation is
defined for 3 floors in experimental region. The free space model and
dual slope models are modified by considering the influence of
corridor conditions on each floor. Using these models, indoor signal
attenuation can be estimated in modeling of indoor radio wave
propagation. These results and modified models can also be used in
planning the networks of future personal communications services.
Abstract: This paper proposes a fast tree join scheme to provide
seamless multicast handover in the mobile networks based on the Fast
Mobile IPv6 (FMIPv6). In the existing FMIPv6-based multicast
handover scheme, the bi-directional tunnelling or the remote
subscription is employed with the packet forwarding from the previous
access router (AR) to the new AR. In general, the remote subscription
approach is preferred to the bi-directional tunnelling one, since in the
remote subscription scheme we can exploit an optimized multicast
path from a multicast source to many mobile receivers. However, in
the remote subscription scheme, if the tree joining operation takes a
long time, the amount of data packets to be forwarded and buffered for
multicast handover will increase, and thus the corresponding buffer
may overflow, which results in severe packet losses. In order to reduce
these costs associated with packet forwarding and buffering, this paper
proposes the fast join to multicast tree, in which the new AR will join
the multicast tree as fast as possible, so that the new multicast data
packets can also arrive at the new AR, by which the packet forwarding
and buffering costs can be reduced. From numerical analysis, it is
shown that the proposed scheme can give better performance than the
existing FMIPv6-based multicast handover schemes in terms of the
multicast packet delivery costs.
Abstract: Trust and Energy consumption is the most challenging
issue in routing protocol design for Mobile ad hoc networks
(MANETs), since mobile nodes are battery powered and nodes
behaviour are unpredictable. Furthermore replacing and recharging
batteries and making nodes co-operative is often impossible in
critical environments like military applications. In this paper, we
propose a trust based energy aware routing model in MANET.
During route discovery, node with more trust and maximum energy
capacity is selected as a router based on a parameter called
'Reliability'. Route request from the source is accepted by a node
only if its reliability is high. Otherwise, the route request is
discarded. This approach forms a reliable route from source to
destination thus increasing network life time, improving energy
utilization and decreasing number of packet loss during transmission.
Abstract: The Globally Asynchronous Locally Synchronous Network on Chip (GALS NoC) is the most efficient solution that provides low latency transfers and power efficient System on Chip (SoC) interconnect. This study presents a GALS and generic NoC architecture based on a configurable router. This router integrates a sophisticated dynamic arbiter, the wormhole routing technique and can be configured in a manner that allows it to be used in many possible NoC topologies such as Mesh 2-D, Tree and Polygon architectures. This makes it possible to improve the quality of service (QoS) required by the proposed NoC. A comparative performances study of the proposed NoC architecture, Tore architecture and of the most used Mesh 2D architecture is performed. This study shows that Spidergon architecture is characterised by the lower latency and the later saturation. It is also shown that no matter what the number of used links is raised; the Links×Diameter product permitted by the Spidergon architecture remains always the lower. The only limitation of this architecture comes from it-s over cost in term of silicon area.
Abstract: This paper presents design trade-off and performance impacts of
the amount of pipeline phase of control path signals in a wormhole-switched
network-on-chip (NoC). The numbers of the pipeline phase of the control
path vary between two- and one-cycle pipeline phase. The control paths
consist of the routing request paths for output selection and the arbitration
paths for input selection. Data communications between on-chip routers are
implemented synchronously and for quality of service, the inter-router data
transports are controlled by using a link-level congestion control to avoid
lose of data because of an overflow. The trade-off between the area (logic
cell area) and the performance (bandwidth gain) of two proposed NoC router
microarchitectures are presented in this paper. The performance evaluation is
made by using a traffic scenario with different number of workloads under
2D mesh NoC topology using a static routing algorithm. By using a 130-nm
CMOS standard-cell technology, our NoC routers can be clocked at 1 GHz,
resulting in a high speed network link and high router bandwidth capacity
of about 320 Gbit/s. Based on our experiments, the amount of control path
pipeline stages gives more significant impact on the NoC performance than
the impact on the logic area of the NoC router.
Abstract: Everyday the usages of the Internet increase and simply a world of the data become accessible. Network providers do not want to let the provided services to be used in harmful or terrorist affairs, so they used a variety of methods to protect the special regions from the harmful data. One of the most important methods is supposed to be the firewall. Firewall stops the transfer of such packets through several ways, but in some cases they do not use firewall because of its blind packet stopping, high process power needed and expensive prices. Here we have proposed a method to find a discriminate function to distinguish between usual packets and harmful ones by the statistical processing on the network router logs. So an administrator can alarm to the user. This method is very fast and can be used simply in adjacent with the Internet routers.
Abstract: MultiProtocol Label Switching (MPLS) is an
emerging technology that aims to address many of the existing issues
associated with packet forwarding in today-s Internetworking
environment. It provides a method of forwarding packets at a high
rate of speed by combining the speed and performance of Layer 2
with the scalability and IP intelligence of Layer 3. In a traditional IP
(Internet Protocol) routing network, a router analyzes the destination
IP address contained in the packet header. The router independently
determines the next hop for the packet using the destination IP
address and the interior gateway protocol. This process is repeated at
each hop to deliver the packet to its final destination. In contrast, in
the MPLS forwarding paradigm routers on the edge of the network
(label edge routers) attach labels to packets based on the forwarding
Equivalence class (FEC). Packets are then forwarded through the
MPLS domain, based on their associated FECs , through swapping
the labels by routers in the core of the network called label switch
routers. The act of simply swapping the label instead of referencing
the IP header of the packet in the routing table at each hop provides
a more efficient manner of forwarding packets, which in turn allows
the opportunity for traffic to be forwarded at tremendous speeds and
to have granular control over the path taken by a packet. This paper
deals with the process of MPLS forwarding mechanism,
implementation of MPLS datapath , and test results showing the
performance comparison of MPLS and IP routing. The discussion
will focus primarily on MPLS IP packet networks – by far the
most common application of MPLS today.
Abstract: The wireless mesh networks (WMNs) are emerging technology in wireless networking as they can serve large scale high speed internet access. Due to its wireless multi-hop feature, wireless mesh network is prone to suffer from many attacks, such as denial of service attack (DoS). We consider a special case of DoS attack which is selective forwarding attack (a.k.a. gray hole attack). In such attack, a misbehaving mesh router selectively drops the packets it receives rom its predecessor mesh router. It is very hard to detect that packet loss is due to medium access collision, bad channel quality or because of selective forwarding attack. In this paper, we present a review of detection algorithms of selective forwarding attack and discuss their advantage & disadvantage. Finally we conclude this paper with open research issues and challenges.
Abstract: A concept of switched beam antennas consisting of
2×2 rectangular array spaced by λ/4 accompanied with a null locating
has been proposed in the previous work. In this letter, the
performance evaluations of its prototype are presented. The benefits
of using proposed system have been clearly measured in term of
signal quality, throughput and delays. Also, the impact of position
shift which mesh router is not located on the expected beam direction
has also been investigated.
Abstract: Mobile Ad hoc Network (MANET) is a wireless ad hoc self-configuring network of mobile routers (and associated hosts) connected by wireless links, the union of which forms an arbitrary topology, cause of the random mobility of the nodes. In this paper, an attempt has been made to compare these three protocols DSDV, AODV and DSR on the performance basis under different traffic protocols namely CBR and TCP in a large network. The simulation tool is NS2, the scenarios are made to see the effect of pause times. The results presented in this paper clearly indicate that the different protocols behave differently under different pause times. Also, the results show the main characteristics of different traffic protocols operating on MANETs and thus select the best protocol on each scenario.
Abstract: A mobile ad hoc network is a network of mobile nodes
without any notion of centralized administration. In such a network,
each mobile node behaves not only as a host which runs applications
but also as a router to forward packets on behalf of others. Clustering
has been applied to routing protocols to achieve efficient
communications. A CH network expresses the connected relationship
among cluster-heads. This paper discusses the methods for
constructing a CH network, and produces the following results: (1)
The required running costs of 3 traditional methods for constructing a
CH network are not so different from each other in the static
circumstance, or in the dynamic circumstance. Their running costs in
the static circumstance do not differ from their costs in the dynamic
circumstance. Meanwhile, although the routing costs required for the
above 3 methods are not so different in the static circumstance, the
costs are considerably different from each other in the dynamic
circumstance. Their routing costs in the static circumstance are also
very different from their costs in the dynamic circumstance, and the
former is one tenths of the latter. The routing cost in the dynamic
circumstance is mostly the cost for re-routing. (2) On the strength of
the above results, we discuss new 2 methods regarding whether they
are tolerable or not in the dynamic circumstance, that is, whether the
times of re-routing are small or not. These new methods are revised
methods that are based on the traditional methods. We recommended
the method which produces the smallest routing cost in the dynamic
circumstance, therefore producing the smallest total cost.
Abstract: With the advance of information technology in the
new era the applications of Internet to access data resources has
steadily increased and huge amount of data have become accessible
in various forms. Obviously, the network providers and agencies,
look after to prevent electronic attacks that may be harmful or may
be related to terrorist applications. Thus, these have facilitated the
authorities to under take a variety of methods to protect the special
regions from harmful data. One of the most important approaches is
to use firewall in the network facilities. The main objectives of
firewalls are to stop the transfer of suspicious packets in several
ways. However because of its blind packet stopping, high process
power requirements and expensive prices some of the providers are
reluctant to use the firewall. In this paper we proposed a method to
find a discriminate function to distinguish between usual packets and
harmful ones by the statistical processing on the network router logs.
By discriminating these data, an administrator may take an approach
action against the user. This method is very fast and can be used
simply in adjacent with the Internet routers.
Abstract: The Mobile Ad-hoc Network (MANET) is a collection of self-configuring and rapidly deployed mobile nodes (routers) without any central infrastructure. Routing is one of the potential issues. Many routing protocols are reported but it is difficult to decide which one is best in all scenarios. In this paper on demand routing protocols DSR and DYMO based on IEEE 802.11 DCF MAC protocol are examined and characteristic summary of these routing protocols is presented. Their performance is analyzed and compared on performance measuring metrics throughput, dropped packets due to non availability of routes, duplicate RREQ generated for route discovery and normalized routing load by varying CBR data traffic load using QualNet 5.0.2 network simulator.
Abstract: Routing security is a major concerned in Wireless
Sensor Network since a large scale of unattended nodes is deployed
in ad hoc fashion with no possibility of a global addressing due to a
limitation of node-s memory and the node have to be self organizing
when the systems require a connection with the other nodes. It
becomes more challenging when the nodes have to act as the router
and tightly constrained on energy and computational capabilities
where any existing security mechanisms are not allowed to be fitted
directly. These reasons thus increasing vulnerabilities to the network
layer particularly and to the whole network, generally. In this paper,
a Dynamic Window Secured Implicit Geographic Forwarding
(DWSIGF) routing is presented where a dynamic time is used for
collection window to collect Clear to Send (CTS) control packet in
order to find an appropriate hoping node. The DWIGF is expected to
minimize a chance to select an attacker as the hoping node that
caused by a blackhole attack that happen because of the CTS rushing
attack, which promise a good network performance with high packet
delivery ratios.
Abstract: Network on Chip (NoC) has emerged as a promising
on chip communication infrastructure. Three Dimensional Integrate
Circuit (3D IC) provides small interconnection length between layers
and the interconnect scalability in the third dimension, which can
further improve the performance of NoC. Therefore, in this paper,
a hierarchical cluster-based interconnect architecture is merged with
the 3D IC. This interconnect architecture significantly reduces the
number of long wires. Since this architecture only has approximately
a quarter of routers in 3D mesh-based architecture, the average
number of hops is smaller, which leads to lower latency and higher
throughput. Moreover, smaller number of routers decreases the area
overhead. Meanwhile, some dual links are inserted into the bottlenecks
of communication to improve the performance of NoC.
Simulation results demonstrate our theoretical analysis and show the
advantages of our proposed architecture in latency, throughput and
area, when compared with 3D mesh-based architecture.
Abstract: A subjectively influenced router for vehicles in a fourjunction
traffic system is presented. The router is based on a 3-layer
Backpropagation Neural Network (BPNN) and a greedy routing
procedure. The BPNN detects priorities of vehicles based on the
subjective criteria. The subjective criteria and the routing procedure
depend on the routing plan towards vehicles depending on the user.
The routing procedure selects vehicles from their junctions based on
their priorities and route them concurrently to the traffic system. That
is, when the router is provided with a desired vehicles selection
criteria and routing procedure, it routes vehicles with a reasonable
junction clearing time. The cost evaluation of the router determines
its efficiency. In the case of a routing conflict, the router will route
the vehicles in a consecutive order and quarantine faulty vehicles.
The simulations presented indicate that the presented approach is an
effective strategy of structuring a subjective vehicle router.
Abstract: Internet is without any doubt the fastest and effective mean of communication making it possible to reach a great number of people in the world. It draws its base from exchange points. Indeed exchange points are used to inter-connect various Internet suppliers and operators in order to allow them to exchange traffic and it is with these interconnections that Internet made its great strides. They thus make it possible to limit the traffic delivered via the operators of transits. This limitation allows a significant improvement of the quality of service, a reduction in the latency time just as a reduction of the cost of connection for the final subscriber. Through this article we will show how the installation of an IXP allows an improvement and a diversification of the services just as a reduction of the Internet connection costs.