MODIFIED PASSIVE AVAILABLE BANDWIDTH ESTIMATION IN IEEE 802.11 WLAN

Quality of Service provisioning for real-time multimedia applications is largely determined by a network’s available bandwidth. Until now, there is no standard method for estimating bandwidth on wireless networks. Therefore, in this study, a mathematical model called Modified Passive Available Bandwidth Estimation (MPABE) was developed to estimate the available bandwidth passively on a Distributed Coordination Function (DCF) wireless network on the IEEE 802.11 protocol. The mathematical model developed was a modification of three existing mathematical models, namely Available Bandwidth Estimation (ABE), Cognitive Passive Estimation of Available Bandwidth V2 (cPEAB-V2), and Passive Available Bandwidth Estimation (PABE). The proposed mathematical model gave emphasis on what will be faced to estimate available bandwidth and will help in building strategies to estimate available bandwidth on IEEE 802.11. The developed mathematical model consisted of idle period synchronisation between sender and receiver, the overhead probability occurring in the Medium Access Control (MAC) layer, as well as the successful packet transmission probability. Successful packet transmission was influenced by three variables, namely the packet collision probability caused by a number of neighbouring nodes, the packet collision probability caused by traffic from hidden nodes, and the packet error probability. The proposed mathematical model was tested by comparing it with other relevant mathematical models. The performance of the four mathematical models was compared with the actual bandwidth. Using a series of experiments that have been performed, it was found that the proposed mathematical model is approximately 26% more accurate than ABE, 36% more accurate than cPEABV2, and 32% more accurate than PABE.

PERBANDINGAN ROUTING PROTOCOL EXTERIOR BGP VERSI 4 DENGAN ROUTING INTERIOR EIGRP PADA ALGORITMA LINKSTATE MENGGUNAKAN PARAMETER PACKET LOSS

- Computer networks very influential on the speed of transferring data from one computer to another computer by using a PC or server, in this case, the routing configuration is very influential. The best routing route selection is the solution to determine the most rapid and efficient routing, and as the best routing consideration, the researcher has examined two routings, namely BGP (Border Gateway Protocol) routing and EIGRP (Enhanced Interior Gateway Routing Protocol) using the Cisco Paket Traccer application. After the researcher was done an experiment, the researcher gets the result of the average EIGRP delay that is 54.619 and the packet loss result between EIGRP and BGP is not available (successful packet delivery). Keywords - BGP Routing Protocol Exterior, EIGRP Interior Routing, Algorithm Link state, Packet loss Abstrak - Jaringan komputer sangat berpengaruh pada kecepatan transfer data antar satu komputer ke komputer lain baik itu pc maupun server, dalam hal ini konfigurasi routing sangat berpengaruh. Pemilihan jalur routing terbaik merupakan solusi untuk menentukan routing yang paling cepat dan efisien, dan sebagai bahan pertimbangan routing terbaik penulis meneliti dua routing yakni routing BGP (Border Gateway Protocol) dan routing EIGRP (Enhanced Interior Gateway Routing Protocol) mengguanakan aplikasi Cisco Packet Traccer. Setelah dilakukannya percobaan yang penulis perbuat, maka didapatkan hasil dari rata-rata delay EIGRP yaitu 54,619 dan hasil dari packetloss antara EIGRP dan BGP tidak ada (pengiriman paket sukses). Kata Kunci - Routing Protocol Exterior BGP, Routing Interior EIGRP, Algoritma Link state, Packet loss.

Cooperative packet-forwarding strategies in mobile ad hoc networks with unreliable channels: An evolutionary game approach

In mobile ad hoc networks, network nodes accomplish a target task usually by cooperative packet forwarding from the source to the destination. It is a challenge to enforce their mutual cooperation for a node’s self-interest. In this article, we focus on cooperative packet forwarding in a one-hop unreliable channel, which leads to packet loss and retransmission. We model the process of packet forwarding with the nodes’ remaining energy and reputation value. We propose a packet-forwarding non-cooperative game model reflecting the utilities of different packet-forwarding strategies, in which an incentive mechanism is introduced to enforce cooperation of packet forwarding. Furthermore, we analyze the packet-forwarding game with replicator dynamics and derive and prove three theorems. If the conditions of the theorems are met, the evolutionarily stable strategies can be attained. Three inferences also reveal how convergence speed to evolutionarily stable states is affected by the cooperative incentive, the probability of successful packet transmissions, and the upper limit of the retransmission number. The simulation results support the proposed theorems and inferences. In addition, we show that our game model with a reputation value and the mechanism of incentive cooperation can improve the probability of successful packet transmissions, and reduce the network overhead.

PC-APC Schemes in Multipath Diversity System to Get Higher Throughput

This paper is studied about a new protocol of Packet combining (PC) and Aggressive Packet Combining Scheme (APC) in multipath diversity system to get higher throughput. In the proposed protocol of PC and APC schemes, two and three copies of a packet are sent in two and three paths. If either of the copies is received without any erroneous then select the correct one and discard all other copies. Again if all copies are found as erroneous then combine the erroneous copies and perform XOR operation in case of PC and bit by bit majority logic in case of APC in order to get the original copy. The paper is implemented using Mat lab and found that new proposed protocols are getting higher throughput and probability of receiving successful packet at the receiver side. Thus, performance of error prone wireless network can be improved by applying either PC or APC in multipath diversity system.

Scalable Architecture for Heterogeneous Environment

Along with the heterogeneous devices, Web-based content increases the necessity for computational services. However, recent trends make it difficult to execute such computations at the terminal side, whereas service providers often allow computations during different load operations. Many computational services are using conventional distributed systems, which provide successful packet transmission in IP networks. In this chapter, proxy architecture and its related tasks are discussed. Some of the necessary requirements, such as incremental scalability, 24x7 availability, and cost-effectiveness, are recognized for scalable network services. To administrate a large cluster and to construct a cluster-based scalable network services, a layered architecture is recommended. This architecture captures the scalable network service requirements and utilizes service-programming models to perform Transformation, Aggregation, Caching, and Customization (TACC) of Internet substance. For better performance, the architecture with the TACC programming model uses data semantics to create novel network services.

Optimal Hidden Node Area for Enhancing Routing Protocol Performance in IEEE 802.11 Multihop MANETs

The prevalence of hidden node areas in IEEE 802.11 multihop MANETs continues to hinder the performance of routing protocols. This letter presents an analytical model that relates the hidden node area to the hop distance between two communicating nodes. Unlike descriptions from the literature, we describe the hidden node area in terms of multiple layers and the different levels of interference contributed by each layer. We then develop mathematical expressions to determine the probability of successful delivery and end-to-end delay of a packet transmitted over multiple hops to a receiver node exposed to hidden nodes, as a function of hop distance. The numerical results show that decreasing the hop distance increases the probability of successful packet reception at a receiver, at the cost of increased end-to-end delay. However, using a specified delay objective, routing protocols can institute a hop distance threshold metric to limit the number of transmissions that produce collisions in the hidden node area and, thus, maximize their performance.