Chameleon Devices: Investigating More Secure and Discreet Mobile Interactions via Active Camouflaging

Many users value the ability to have quick and frequent sight of their mobiles when in public settings. However, in doing so, they expose themselves to potential risks, ranging from being targets of robbery to the more subtle social losses through being seen to be rude or inattentive to those around them. In nature, some animals can blend into their environments to avoid being eaten or to reduce their impact on the ecosystem around them. Taking inspiration from these evolved systems we investigate the notion of chameleon approaches for mobile interaction design. Our probes were motivated, inspired and refined through extended interactions with people drawn from contexts with differing ranges of security and privacy concerns. Through deployments on users’ own devices, our prototypes show the value of the concept. The encouraging results motivate further research in materials and form factors that can provide more effective automatic plain-sight hiding

S-OSPF: A Traffic Engineering Solution for OSPF Based Best Effort Networks

Open Shortest Path First (OSPF) is one of the most widely used intra-domain routing protocol. It is well known that OSPF protocol does not provide flexibility in terms of packet forwarding to achieve any network optimization objective. Because of the high cost of network assets and commercial and competitive nature of Internet service provisioning, service providers are interested in performance optimization of their networks. This helps in reducing congestion hotspots and improving resource utilization across the network, which, in turn, results in an increased revenue collection. One way of achieving this is through Traffic Engineering. Currently traffic engineering is mostly done by using MPLS. But legacy networks running OSPF would need to be upgraded to MPLS. To achieve better resource utilization without upgrading OSPF network to MPLS is a challenge. In this paper we present a simple but effective algorithm, called Smart OSPF (S-OSPF) to provide traffic engineering solution in an OSPF based best effort network. We formulate an optimization problem based on the traffic demand to minimize the maximum link utilization in the network. Routing of the traffic demand is achieved using OSPF. We have simulated S-OSPF on real networks of two service providers. Simulation results show that S- OSPF based traffic engineering solution performance very closely follows the optimal solution

A local coefficient based load sensitive routing protocol for providing QoS

In an Open Shortest Path First (OSPF) based best effort network, the OSPF shortest path can become the bottleneck when congestion occurs. OSPF cannot forward packets though less congested alternate paths. Hence, OSPF cannot be used to provide Quality of Service. Earlier, we reported a Load Sensitive Routing (LSR) algorithm which finds alternate path based on OSPF property. In the earlier work, the LSR used global coefficients i.e. all the nodes in the network use the same coefficient for a given destination. But assigning network-wide global coefficient may lead to uneven distribution of alternate paths. That is, some nodes may have many alternate paths whereas others may have few or none. The use of global coefficient was thought to be necessary to make the protocol loop free. In this study, we allow nodes to choose LSR coefficients locally (we call the coefficient L-LSR coefficient) while still retaining the loopfree property. This leads to nodes having more number of alternate paths than the case where they had to use global coefficient. But allowing local coefficients makes the process of calculating the local coefficients complex. Since our protocol has to be loop free, the local coefficients have to be calculated such that the loop free OSPF property is still satisfied. This paper presents detailed algorithm for calculating L-LSR coefficients. Using simulation, we show that L-LSR algorithm not only performs better than OSPF, but also has very significant performance improvement over the other LSR family of algorithms. 1

A Contention Window Based Differentiation Mechanism for providing QoS in Wireless LANs

Running real time applications over wireless LANs is becoming common place. These applications require QoS. But the most widely used wireless LAN, IEEE 802.11, does not have QoS support. Hence, providing QoS in 802.11 WLANs is an important issue due to its large installation base. In this paper, we propose a priority based service differentiation mechanism at the MAC layer. The MAC assigns different contention windows to two priority classes to provide service differentiation. The MAC protocol was designed such that minimal change is required in 802.11 firmware and yet the performance is comparable to 802.11e MAC. When collision occurs, contention window is increased in a linear fashion and the new contention windows for high and low priority traffic become non-contiguous. This unique method of contention window management provides better relative performance between the two classes. We also propose an enhancement to our base protocol that further increases throughput at light load condition. We present our simulation experiment results that show that our protocol has performance comparable to 802.11e.© IEE