Network design case study with diagram creation tools

¶ … Wireless Network Design Proposal

Apparently, technology has influenced many fields and education is not an exception. Students can now access education from different locations in the globe, a factor that has contributed to the development of the education sector. In addition, students can access lectures through the internet, lecturers can share information through live-conferencing, and this has led to further development of the education sector. The case study provided aims to develop a network, which will cater for the anticipated growth of the institution, allow for distance learning via live broadcasting, desktop screen sharing and digital video conferencing. In addition, this paper utilizes prior and current information concerning wireless networks to design a network, which will cater for the institution's needs.

Table of Contents

Introduction

Business Goals

Technical Goals

Case Study

Network design Proposal

Mesh Network

802.11 Access Points 8

Architecture of Learning and Teaching 8

Block Structure 8

Design Considerations 9

Detail Structure 10

Important Applications 10

Server Hardware 11

Operating System 11

Media Server (Software 11

Web Servers 11

Mail Servers 11

Proposed Estimate Budget 11

References 12

Appendices 13

Figure 1 13

Figure 2 14

Figure 3 15

Introduction

Distance learning, which may include correspondence courses, continuous education, satellite universities, mega universities, and open universities, is among the most current ways of confronting education challenges in higher education systems. However, the methods and media used to deliver distance learning, which include print, instructional radio, instructional television are not effective. Prior studies suggest that students value timely feedback concerning their assignments, examinations and various school projects. The mentioned methods of delivery lack timely feedback (Brewer et al., 2006). Currently, there is increased advancement in technology, an aspect, which has seen to rapid development of computer networks, progress in processing power of personal computers, and advancement in magnetic storage technology.

Business Goals

These advancements have made the computer a dynamic force in distance learning, and subsequently created a new means of overcoming time and distance to reach students. Networks provide timely feedback, which can maximize learner control. Prior studies further suggest that the existing methods of distance learning are single media, which is, either text, or voice. Notably, in campuses, the use of computers is rampant, but the lack of a network to interconnect these computers makes their value limited (Zhang and Nunamaker, 2005). This project seeks to develop a wired LAN, and makes use of new approaches to wireless mesh networking to cater for the distance-learning program in NIT. In addition, the wireless mesh network comprises a number of routers, whereby each is equipped with adaptive mesh that allows routers to relay data through multiple routing hops.

Technical Goals

Generally, routers are placed on rooftops, and they utilize high-gain antenna to provide long-range distance between routers. In addition, attached to the different routers is a bridge to a LAN, which is either a wired Ethernet LAN or separate access points. The users connect to the network using a desktop or laptop, which will associate with the nearest access points. The mesh networks offer wireless distribution network between the separate local area networks (Tellis and Zamora, 2005). Such networks have proven reliability and have attracted attention in developing network accessibility in remote areas, and learning institutions. This project aims to design a wireless network, which will achieve the objectives of the management, which include:

1) Allowing online live broadcasting

2) Wireless access to campus for both students and visitors

3) Desktop screen sharing

4) Digital video conferencing

Case Study

North south Institute of Technology, founded in 2000, provides higher education locally and internationally. Currently, the institution has three city campuses in Sydney, Melbourne, and Brisbane. Each of the campuses has around 50 staff and around 700 students, newly enrolled. In addition, the institution has an outstanding reputation for its excellence in teaching, exceptional student services, and graduate employability, factors that are contributing to its rapid growth. In addition, there is a likelihood that the institution will grow further.

Anticipating for this, the school has opted to expand by opening another institution in Adelaide, and the existing universities by 10%. Therefore, the NIT institution is considering an option of establishing a distance-learning program because NIT has a limitation of space. The institution plans to implement distance learning with few courses, but the school will increase the courses after the program succeeds. The live broadcasting will take place from Sydney campus. Currently, there is no wireless network in the institution, but the growing demand of wireless access is wanting.

In addition, the management feels this is a good idea. The school also intends to establish desktop screen sharing and an online meeting facility, which will make it possible for staff from the various campuses to work together and improve the learning program. The school also intends to equip the meeting rooms with high quality video conferencing, desktop screen sharing facilities, and wireless area network to support. On the other hand, the school recognizes the need for security, which should be considered in the design.

Network Design Proposal

Figure 1 represents the overall design of the proposed wireless mesh network, which consists of mesh router nodes, which is core to the entire network, combined with multihop routing. In addition, the wireless access points will provide a connection to the end users, network switches, which will connect the access points to the routers in each building. Moreover, there will be single routers on roofs of each building (main buildings) on the different campuses. The users, who include students, visitors, staff and management, will access the internet connection via 802.11 network-using laptops, or desktops, which are equipped with wireless interfaces.

Mesh Network

A wireless mesh network comprises several router nodes, which form a wireless distribution network, which typically are over a standard 802.11a/b/g links. In addition, the mesh routers form an ad hoc network for conveying packets. Nevertheless, routing protocols implemented by routers can be highly vulnerable to packet loss, interruption, congestion, or failure of individual routers. However, this happens when there is the selection of optimal routing paths based on measurements of connection quality and path loss. Routing based on ETX protocol selects routes based on a measurement of the expected transmission count for the packets to ensure proper reception. There is another option, which is the utilization of distance-vector protocols to build the routing paths (Dung and Malik, 2011).

In the proposed design, the mesh routers are placed on the rooftops of the campus buildings, and the routers comprise of cheap embedded PC with reasonable processing capability and memory, alongside an 802.11 g interface and a high gain directional antenna. In addition, it is possible to consider using commercial mesh networking solutions (Crow et. al., 1997), for instance, solutions found on the Cisco Aironet 1500, which has high performance and network capacity. This approach is ideal because the failure of a single router, on any of the campuses, will only lead to loss of connectivity and reduced capacity, but not the failure of the whole network. In addition, it is possible to mitigate localized packet loss, which might be due to interruption or heavy load through dynamic route selection. For instance, it is possible to load balance multiple flows traversing the network across separate paths. The mesh approach allows expansion of the capacity and coverage of the network by adding other routers.

This mesh design approach references entirely on the Roof Net project at MIT, which demonstrates a city-scale mesh network, which is central to 802.11b. In addition, Roof Net comprises of 40 mesh routers deployed on the rooftops across the city of Cambridge, Massachusetts (Brewer et al., 2006). Moreover, each router provides an Ethernet connection, which allows the user hosting the router node to access the network through the mesh network. There is the connection of several mesh routers directly to the MIT campus network, which further serve as gateways to the public internet connection. There has been several other deployment of the design in Berlin. Owing to the vastness of such cities, it is apparent that the design will work well to serve the identified purpose of the NIT institution.

802.11 Access Points

The second phase of this proposed design is the series of 802.11b/g access points, which are linked to each other via an Ethernet switch (Crow et al., 1997). The access points make it possible to access the internet connection to end users, most of which are students, staff and management. They will access the connectivity using laptops, or desktops equipped with a wireless interface cards (Crow et al., 1997). Owing to the large size of enrolment, which is assumed will increase; each of the main building can have 10 access points for each mesh router in order to provide connectivity to the main lecture hall, libraries, and other areas around the campuses. Moreover, it is possible to extend the network by adding access points. Although it is possible to programme the mesh routers to serve as both access points and primary routers, it is important to acknowledge the problems associates with this configuration. For instance, supporting both backbone routing and wide area network functionality on the router can increase complexity, which may contribute to poor scalability.

Architecture of Learning and Teaching

In Figure 2, it shows the conceptual framework between two remote areas, in our case, it is the model, which shows two different campuses. The framework presents the system for online teaching, and distance learning, which is central to block structure, design considerations, and detail structure.

Block Structure

The approach has three stations, which include lecture capture station, lecture file server station and lecture view station. The lecture caption station comprise of hardware and software used for digitizing and compressing video signals. In addition, it has workstations equipped with video cameras, microphone and software to capture video. On the other hand, the lecture server station is responsible for streaming the media files, from the lecture halls to enhance distance learning. The streaming technology supports live video, which is the primary element in online lecturing or live broadcasting. In addition, the lecture view station is where the course lectures take place either live or after storage. The station decompresses video streams and displays the video on the display unit. Speakers or headphones play a role in playing the audio aspect of the video. The lecture view station comprises a workstation equipped with the video card, speakers, video player software, which includes a projector for playing back lectures on screen (Akintola and Akinyokum, 2011).

Design Considerations

Some of the issues include computer network topology, messages transmission media, and protocol for transmitting messages, and website design to enhance online lectures in distance learning. Considering that teaching and learning are processes that involve broadcasting signals from a source to several targets, this proposal recommends a star-ring topology. The stations at the lecture capture station can communicate through the server. In addition, cabled network and wireless network co-exist and cooperate in the system. The objective of the communication system is to relay information, and comprise of a transmitter, receiver and a channel, which links the transmitter with the receiver. For this wireless case, a Radio spread spectrum, which has wideband radio frequency, will trade off bandwidth efficiency to enhance reliability, integrity and security. In addition, this paper proposes the use of MPEG-1 for compressing video, and maximizes video quality during live broadcasting, online lecturing and enhances distance learning (James and Gardner, 1995).