By:       Muhammad Emran

The documentation for mobile communication has grown remarkably in the last few years. An efficient allocation of communication channels is essential for ensuring good performance of cellular networks provided the limit spectrum is available.

Previous work on load balancing in advanced mobile phone services (AMPS) cellular networks has led to several channel allocation schemes to maximize the channel usage and minimize the call blocking probability.

This thesis comprises of an implementation and analysis of active channel allocation (ACA) scheme using OPNET simulator. It also consists of comparisons between fixed channel allocation (FCA) and the developed active channel allocation (ACA) schemes.

 The work in this thesis demonstration that active channel allocation produced improved results as compared to fixed channel allocation scheme. After the implementation of active channel allocation scheme, the average blocking calls were reduce to reasonable level and hence serviced calls were reduced to reasonable level and hence serviced calls were increased adequately under the same load over the network. This proves that active channel allocation scheme performs better than the fixed channel allocation scheme.     

By:       Hafiz Muhammad Zeeshan

Hafiz Shahid Iqbal

There is a need for internetworking between telephone and computer networks. Applications such as Voice over IP (VOIP) and the deployment of the 3^rd generation mobile telephony networks, make this integration a necessity.

The signaling transport (SIGTRAN) working group of the Internet Engineering Task Force (IETF) is the one in charge of the design of the standard needed to make this internetworking possible. The primary purpose of this working group is addressing the transport of packet-based public switched telephone network (PSTN) signaling over IP networks, taking into account functional and performance requirements of PSTN signaling. Among the multiple standards that have been defined by SIGTRAN there is one new reliable transport protocol, the Stream Control Transmission Protocol (SCTP). SCTP is the evaluation of a previous transport protocol, called the Multi- Network Datagram Transmission Protocol (MDTP), highly based on TCP [5].           

SCTP has several new features that make it more suitable for PSTN signaling transport than TCP. SCTP can take advantage of a multi homed host using all the IP addresses the host owns. SCTP avoids a very simple attack that affect TCP, the so called SYN attack. This new protocol also provides a mechanism to prevent and application using SCTP from the so called Head-Of-Line (HOL) blocking by using stream. Moreover, many features that are optional in TCP have been including in the basic specification of SCTP, such as the Selective Acknowledgment, the ability to tell about the receipt of Duplicate Datagram or the support for Explicit Congestion Notification (ECN) [2].

This thesis discusses the evaluation of the design of SCTP. We will try to explain why the different aspects of SCTP were designed in the way they were designed and its efficiency against other protocol suit like TCP and UDP specially when transferring media traffic like MPEG formatting stream. When possible, we will explain how the characteristics of SCTP evolved from the initial MDTP’s ones, and we will show how SCTP and TCP behave in similar situations and the performance against UDP for MPEG4 video streaming in graphical representation. We will simulate the SCTP by implementing a new algorithm to control congestion state.  

By:       Abdul Basit

ADHOC wireless networks are self organizing multi-hop wireless networks where all nodes take part in the process of forwarding packets [1]. MANETs consist of mobile nodes, which communicate via wireless means and perform the tasks of both hosts and routers. MANETs do not have a centralized controller, nor do they require any infrastructure, that is why MANETs are also known as infrastructure- less networks [2]. The network topology of MANETs is dynamic as mobile nodes are free to move around and can even freely leave or join the network. Dynamic and free movement of MNs in MANETs causes lack of link stability; this is major problem because of which this topic has been adopted to enhance the throughput using weighted mobility awareness factors. The purpose of this thesis is to improve performances of OADV by presenting a novel scheme called direction Awareness. This scheme is based on based on weighted measurement of two mobility factors i.e. direction and distance for a best node. Based on these weights play an important role to select best route using est node that sustains for longer period of time, resulting in high throughput and less delays that enhance performance of AODV networks.

By:       Amjad Ali          

The transmission control protocol (TCP) is the most predominant transport layer protocol in the internet today. It transport majority of the traffic on the internet. TCP in its traditional form was design and optimized for wired networks. In traditional TCP Packet loss is mainly attributed to the network congestion in which TCP transmitter invokes congestion avoidance and error recovery mechanisms which reduce its congestion window size. In TCP persistent packet reordering attack, The malicious nodes persistently reorder packets after placing them into reordered buffer rather than placing into FIFO buffer. The TCP receiver generates DUPACKs on receipt of out-of-order packets. The problem arise when TCP transmitter misinterprets these DUPACKs as packet loss and invokes its congestion avoidance avoidance mechanisms which reduces its congestion window size unnecessarily and generate large number of unnecessary transmission. Thus, this persistent packet reordering will result in near zero good put, Instead of all transmission packets has been delivered.

The objective of this thesis is to analyze the behavior of congestion window size of standard TCP and many other variants of TCP such as TCPReno, TCPNewreno, TCPSack1, TCPVegas, TCPRbp and TCPFack with different ad hoc routing protocols such as AODV and DSR under persistent packet reordering attack as a case study we have analyzed the state transition diagram for TCPReno by Katsuhiro et al, and show how this TCP variant misinterprets packet reordering with packet loss, in order to handle such misinterprets packet reordering with packet loss. In order to handle such misinterpretations, we have introduced two new states in TCPReno. The state “Rf” eliminates the retransmission ambiguity that is due to receipt of three successive DUPACKs and “Rw+f+0” eliminates the spurious timeout ambiguity that is due to the receipt of DUPACKs less than three. These two new states prevent TCPReno to reduce its congestion window size unnecessarily when retransmissions are due to persistent packet reordering attack rather than packet loss.

This thesis comprises of an implementation of persistent packet reordering attack under standard TCP and analysis of this attack under various TCP variants by using different ad hoc routing protocols such as AODV and DSR through NS-2 simulator. An analytical solution is proposed to handle said attack in TCPReno. 

By:       M Sajid Qayyum 

The channel reliability and congestion has many facets and encompasses more than the packet routing and delivery of the packets. In wireless ad hoc network congestion causes overall channel quality to degrade and increase in loss rate, Increase in delay, retransmission, flooding, channel access contention, decrease in throughput of networks and increase in transmission interface queue length. A large number of reactive and proactive protocols have been proposed in recent years to control congestion at different layers. The media access control (MAC) layer plays a key role in determining the channel usage efficiency by resolving contention, transmission from independent nodes separated in time and space. The IEEE 802.11 MAC contention based protocols help to mitigate congestion in ad hoc wireless networks to a large extent by channel reservation it avoids hidden node and exposed terminal problems. By local monitoring of the network interface transmission queue length and MAC layer behavior at each node can make a decision about the channel condition around it. To improve quality of service, MAC layer fragmentation and De-Fragmentation is important, that can be used by devising adaptive algorithms. Buffer occupancy and packet drop rate are the major parameters effecting congestion.

The proposed Congestion Aware Nodes (CAN) based scheme improves working of Dynamic Source Routing (DSR) for congestion at MAC layer. In this scheme congestion is detected by using different MAC layer parameters i.e. queue delay, packet retransmission and MAC overhead. These parameters are used by DSR to select less congested link at the routing layer. The simulation results how that proposed scheme works well in a congested network with less retransmissions, low packet loss, less delay and higher through put.

By:       Kamran Yousaf

Packet scheduling technique to be used is very crucial to provide the quality of service. This thesis implements a router scheduler in programmable logic using Xilinx FPGA (Spartan 3). The FPGA’s are configurable, reprogrammable and can be designed in no time. FPGA allow customizable and easy modifications of the hardware design. While router at its input ports receiving packets and putting them in packet buffer, some parameters (type of service, Packet length, and source IP address) that are present in packet header are examined and the priority is calculated based on these parameters. Priority calculated for each packet tells that how early that packet would be transmitted. When the packet is being placing at packet buffer the request that denotes the buffer location and packet priority is sent to priority queue. Priority holds the request in such fashion that the request with priority 1 will be completed first. The priority is controlled by scheduler. The scheduler is responsible to putting requests into queue and getting request out of queue. The scheduler fetches the packet from the packet buffers according to priority queue and then sends the packet out of router accordingly. Scheduler is responsible for maintaining QOS (Quality of service) so that the data which needs to transmit immediately or that does not compromise delay must be forwarded immediately without any delay. Today in modern communication world, the traffic that exists in the internet is becoming more and more abnormal. This is mainly due to increase in number of users. The most efficient solution to this problem is to manage and allocates the bandwidth using suitable queuing. QAS (Query of Service) means satisfying customer requirements. Objective is to implement real-time packet scheduling algorithm to ensure quality of service (QAS) for different data streams. The router used in this thesis receives or send data parallel. Parallel processing is a technique for improving the performance of computers. The functional description of the router scheduler has been written in the VHDL (Very High Speed Integrated Circuits hardware description language). The fundamental motivation to use VHDL (or its competitor, Verilog) is that VHDL is standard, Technology/ Vendor independent language. The VHDL can bee compiled into a gate level model using hardware synthesis tools.            

By:       Muhammad Iqbal

Field Programmable Gate Array (FPGA) devices offer a large set of advantages due to their-r-configurable nature. Although their performance is not comparable to ASIC devices, their-flexibility is usually more important especially when fast time-to-market is an issue. For that reason they are widely used in electronic applications both during prototyping but also for final-production systems. Computer networks are undoubtedly one of the most demanding areas where flexibility and cost are of significant importance.

The aim of the current thesis is the design and implementation of an FPGA-based constraint based routing. Constraints are the set of values that the link have. For example a matrix, this contains the cost, bandwidth, delay, number of hope counts, and many.

Constraint based routing (CBR) denotes a class of routing algorithms that base path selection decisions o a set of requirements or constraints, in addition to the destination.

In the proposed design these constraints are implemented on the hardware level and all the incoming packets are forwarded on the basis of the constraints.

This will help to maintain the QoS as well as the policy based communication. That means that the final product is a low-cost device can be used from a typical LAN to a more advanced wireless network.

By:       Rizwan Qureshi

Security is essential whether in wired networks or in Mobile Ad hoc Networks (MANETs). In fact it is more necessary in the inherently unsecured MANETs. Nodes join and leave a MANET randomly and there is no way to identify what type of node will be joining. A malicious node joining a MANET can cause havoc. To secure a MANET against attacks by malicious nodes we need to exclude them from any route that a data packet may take. We can define trust levels for each node and dynamically update them according to some metric. Then only nodes which meet a certain criterion are allowed to participate in a route otherwise they are excluded. Simulating the model shows that trust level are a good way to prevent malicious nodes from becoming a part of any route. This helps the efficiency of the network by allowing the maximum number of packets to reach the intended destination.

By:       Rukhsana Rahim Butt

VPN is being thought off a substitute emerged and professed technology of IEEE 802.1x devices for wireless LAN security due to prevailing vulnerabilities in it to avoid extensive configuration, maintenance and finance. Moreover, 802.1x devices are not easily accessible.

Analysis of existing technologies prior to their development is a crucial one that can yield progressive growth/throughput to the organization in case of security and performance. The aim of this thesis is to quantity the impact of various VPN tunnel types on the network performance.

This study comprise of issues related to IEEE 802.11b, pointed out two methods to secure WLAN i.e. 802.1x and VPN, comparison between different tunneling protocols to emulate the pleasures with wired technologies.

RFC 2764 is selected to model and simulate two L2TP tunneling types; voluntary and compulsory. I have followed qualitative and quantitative approach to accomplish my thesis on analysis on various tunnel types for security and performance.

Various tests are conducted on real and non-real applications to check the strengths and weaknesses against each application. This study can help in guiding the service providers and network managers to decide which VPN solution is the right one to use.

By:       Salman Tariq

This investigation provides technical information address in DACS. It is designed for use in conjunction with other DACS documents or as a stand alone reference. Data communications technologies are evolving and expanding at ana unparalleled rate. The growth in demand for internet access and intranet services continues to fuel rapid technical adaptation by both implementers and developers. Unfortunately, creating an information resource such as the investigation on DACS requires certain recognition by its author that some information is likely to be obsolete the day it appears in print.

The project is adopted with intention to give myself a brief introduction in the field of communication. The project provides a comprehensive introduction to the study of DACS. It presents elementary information for Tellabs and Alcatle (New bridge). And special research is made on NMS, that how NMS is controlling Tellabs and Alcate(Newbridge). In end I have given my own comments about Tellabs and Alcate regarding their working.

By:       Salman Akhtr Cheema

Mobile Ad Hoc Networks (MANETs) are multi-hop ad hoc wireless networks with no infrastructure. Network topology of MANETs is dynamic as mobile nodes are free to move around and can even freely leave or join the network. Each Mobile Node (MN) acts either as a host generating flows or as the destination of flows form other MNs or as a router forwarding flows directed to other MNs. Protocol defined for ad hoc networks are classified as reactive protocols. Reactive protocols are characterized by MNs maintaining routes on demand; examples are AODV and DSR (Dynamic Source Routing).

The aim of this project is to improve performance of AODV in multi-hop environments by finding optimal route to the destination. The idea is to find best nodes in the direction of destination. All nodes in the network broadcast their current location to their neighboring nodes periodically within its radio range. Using this location information every node finds its best neighbor by assigning weights to its all neighbors with respect to direction and distance in its radio range. This process continues until a data packet reached to the destination. In this scheme best neighbors are selected to establish an optimal path to the destination and the path remains stable for longer period.

By:       Hasnain Ahamd

A mobile Ad hoc Network (MANET) is a collection of wireless mobile nodes (hosts) forming a temporary network without the help of any established infrastructure or centralized administration. Security of routing protocol in MANET is today a major issue. Correct functioning of MANET can only be guaranteed through reliable routing operation. Here, the security threats against AODV (the most widely used routing protocol in MANETs) protocol and their countermeasures are discussed in detail. Also, a model for establishing trust of neighboring nodes (the nodes that are directly in the radio range of a given node) is proposed and implemented. The proposed model calculates the trust levels of neighboring nodes. These trust levels provide a node the basis for more certain opinions about its neighbors. Using these trust levels a node can choose better neighbors (next hope) in future routes.

By:       Saira Ilyas

Healthcare is of great importance of any country, and so is for Pakistan . Unfortunately, majority of care domains in Pakistan are operating at a sub-optimal level, as the use of information Systems is almost non-existent. An utmost need is to improve the current healthcare services by introducing information Technology. In the absence of a proper enterprise Resource Planning, most of the health care amenities, particularly in government sector, are lacking the best possible outcome. I have proposed the HL7 standard complaint applications for the health care in Pakistan that also incorporates other standards as LONIC, DICOM, ICD-10 and ISO-3166 in it. Also I have analyzed the network performance for transporting the HL7 messages according to the protocols suggested by the HL 7 organization as SSL, HTTP, SMTP and ebXML.

By:       Khawar Mahmood

A mobile as hoc network is a collection of wireless nodes, all of which may be mobile, that dynamically create a wireless network amongst them without using any infrastructure. Ad hoc wireless networks come into being solely by peer-to-peer interactions among their constituent mobile nodes, and it is only such interactions that are used to provide the necessary control and administrative functions supporting such networks. Mobile hosts are no longer just end systems: each node must be able to function as a router as well to ralay packets generated by other nodes. As the nodes move in and out of range with respect to other nodes, including those that are operating as routers, the resulting topology changes must somehow be communicated to all other nodes as appropriate. In accommodating the communication needs of the user applications, the limited bandwidth of wireless channels and their generally hostile transmission characteristics impose additional constraints on how much administrative and control information may be exchanged, and how often. Ensuring effective routing is one the greatest challenges for ad hoc networking.  

By:       Lubna Javaid

The title of the project is “IMS (IP Multimedia Subsystem) and P2P data sharing “. The discussion is on IMS technologies, P2P data sharing in IMS and their impact.

IMS is defined by 3GPP as a new subsystem, i.e. a new mobile network infrastructure that enables the convergence of data, speech and mobile network technology over an IP-based infrastructure. Peer-to-peer (P2P) systems are self organizing architectures, independent of any infrastructure. Self organized makes them robust and flexible to dynamic changes without provider interaction. We will argue that how a user can share applications and data residing on their UEs in IMS by implementing a virtual network, which will enhance the IMS architecture by the implementation of new software logical components and will consequently enhance the services offered by IMS to its subscribers.

The aim of this study is to throw light on the dilemma which has not yet been focused in IMS. Currently, IMS does not support and P2P services.       

By:       Rabia Mahmood

IEEE 802 11 is the most widely used standard in wireless local area networks. It has been recently enhanced in the form of IEEE 802. 11e to provide better support for Quality of service since existing wireless networks have significantly lower bandwidth than the networks with which they are integrated, they easily become the bottleneck for the traffic flow and may get saturated quite often. A number of works have focused on calculating the throughput and delay performance of IEEE 802. 11and the IEEE 802 11e wireless networks The existing models for saturation throughput analysis have some nor do they provide a closed form solution for the performance parameters. Bianchi [2] modeled the binary exponential back off process used by IEEE 802.11 networks, using a two-dimensional Markov chain. Later, many researchers have modified Bianci’s model to incorporate more and more details of the IEEE 802.11 protocol in order to make it more accurate. This model has also been modified for the analysis of IEEE 802.11 by incorporating AIFS and contention window differentiation. However the models found for IEEE 802.11 do not cover the back off freezing due to EIFS which significantly affects the accuracy and correctness of the model. One model [9] that covers EDCA post-collision back off, models EIFS outside the two dimensional Markov model and hence it does not provide a closed form solution. In this thesis, we modify and existing analytical model [12] by including EIFS as defined in the IEEE 802.11e standard. We derive saturation throughput results analytically and verify out results with simulations.