Evaluating benefits of networks and performing network management responsibilities - Essay Example

Evaluating Benefits of Networks and Performing Network Management Responsibilities Part How a Network Works 0 Network Topologies: An Overview 1.1 Advantages & Disadvantages of Networks 1.2 The OSI Reference Model 1.3 What is Data Encapsulation 1.4 TCP/IP Fundamentals 1.5 TCP/IP Networks 1.6 Ethernet LAN topology Part 2: Design of a MAN from 4 LANs 2.0 Choosing the Network Topology for the LANs 2.1 Metropolitan Area Networks [MAN] 2.2 Connecting the LANs: Network Equipment-Hardware & Software 2.3 Workstations & Specifications 2.4 Servers & Specifications 2.5 Network Operating Systems & Specifications 2.6 Client Operating System & Specifications 2.7 Office Application Software & Specifications 2.8 Future Trends in Networking.. 1.0 Network Topologies: An Overview Local Area Networks (LAN) can be described in various configurations and layouts referred to as Network Topology. Network topology determines the connectivity and communications mode of nodes on a network. Topologies are described as either physical or logical. The most popular network topologies are: Bus topology Bus topology provides the simplest network connection. A single cable connects all the computers and network peripherals. Each node communicates with any other node by using the physical address of the network card of the destination node. This physical address is called the Media Access Control (MAC) address. The cables are terminated at both ends. Star topology All network equipment or nodes are connected by cables to a central connection unit, or hub. The nodes communicate with each other via the hub. The hub could be a Server or a Router. The figure below shows a star network wiring. Ring topology In a ring topology, all the nodes are linked in a logical circle. Data circulates from node to node via a connection unit known as Multi-station Access Unit (MAU). Note that a closed loop is formed with the cable returning to the first device Here is an example of a ring network. Mesh topology Devices are connected with many redundant interconnections between network nodes. In a true mesh topology every node has a connection to every other node in the network. As the number of nodes increases, so does the complexity and cost. They are not popular with LANs but are often used in WANs. 1.1 Advantages & Disadvantages of Networks in an Organization The following advantages follow from installing and managing efficiently, a LAN in an organization. Increased productivity: According to Forbes.com a 20% increase in productivity can be attained since less time is wasted searching for files or managing files manually. Data loss reduced :LANs server software provides facilities for automatic file backup and easy retrieval in accidental deletion. Protection of Business Information: Built-in firewall protection and secure remote access guards your network. Other security software are available to protect your network from Internet intruders: spam, e-mail attachments and spammers. Business Access anytime, anywhere: A LAN allows you to connect to your business anytime and from anywhere you have access to the Internet. Improved Team Performance: Your workers can work better as a team when they can share information resident on the LAN and collaborate anytime. Resources Sharing and Costs Reduction: LANs enable your organization to share resources such as Internet access and business software; equipment such as printers. Some of the disadvantages of LANs include the risk of exposure to the evils of the Internet , namely Internet fraud, identity theft, and loss of useful data that was not backed up before a network fails. 1.2 The OSI Reference Model A discussion on networks and network topology will not be complete without mention of the Open Systems Interconnection (OSI) Reference Model. Developed in the late1970s, the OSI reference model provides the framework and guidelines for data transfer and communication between network nodes. Designed on a layered architecture, the OSI consists of seven layers. The top three layers define how communication processes between applications and end-users. The last four layers are concerned with data transmission through a cable, switch or router. It also provides the guidelines for reconstructing a data stream transmission from a host to a destination host's application. The seven layers and their functions are briefly described in the table below. Layer Key Functions 7 Application Application services, Message, File, print & database 6 Presentation Services include data encryption, compression, and translation. 5 Session Dialog control between devices or nodes. 4 Transport Provide end-to-end connection 3 Network Routing, network addressing 2 Data link Formats messages into data frames 1 Physical Physical topology; sends and receives bits. 1.3 What is Data Encapsulation Data Encapsulation involves adding a header to identify data as it passes through the OSI layers. In the encapsulation process, the Application layer, Presentation and Session layers generate data from a user's input. The transport layer converts the data into segments, the network layer then converts the segments into packets or datagrams. The packets are next converted into Frames by the Data-link layer. Finally, the Physical layer converts the frames into bits and bytes. More technically, encapsulation involves the addition of a header---Protocol Control Information (PCI) to data-Service Data Unit (SDU) to form a Protocol Data Unit (PDU) by a layer of the OSI.. The diagram below illustrates this. Encapsulation, it should be noted takes place at each of the OSI layers. Each layer appends a PCI and passes it to the layer below it without worrying about its contents. This process continues until the data reaches the physical layer. The physical layer then serializes the packet into a series of bits and transmits them to a cable to the destination system. Here the bits are re-assembled to form a packet which is then sent to the Link layer. Here the link layer header is removed and passed to the next layer until eventually the original packet data reaches the remote application program. 1.4 TCP/IP Fundamentals TCP/IP stands for Transmission Control Protocol/Internet Protocol. It is a suite of Protocols designed on a four-layered network: Network Interface layer, Internet layer, Transport layer and Application layer. The table below gives a quick overview of TCP/IP with the basic functions of each layer and its protocols. Layer Functions (briefly) Protocols Application Network based applications function at the application layer. Transport Provides end-to-end communication between hosts using ports. TCP provides connection oriented communication. UDP provides connection-less, non guaranteed communication. Transmission Control Protocol (TCP) Universal Datagram Protocol (UDP) Internet ARP returns actual MAC address of the destination host. ICMP provides error reporting and control messaging to the TCP/IP protocol suite Address Resolution Protocol (ARP) Internet Control Message Protocol (ICMP) Internet Protocol (IP) Internet Group Messaging Protocol (IGMP) Network Interface Merges outgoing frames on the wire & pulls incoming frames off the wire. Prevents Data corruption through cyclical redundancy check (CRC). No Protocols 1.5 TCP/IP Networks A TCP/IP based network is a network whose network operating system (NOS) has been configured to implement the TCP/IP protocol. Windows 2003 Server and Windows XP ship with TCP/IP protocol as standard, with details of how to configure them for a network. This usually includes: IP Address, DNS, WINS Address and DHCP Relay. 1.6 Ethernet LAN Topology Ethernet, developed at Xerox in the 1970s, is defined by IEEE 802.3. It makes it possible to connect up to 1024 nodes over twisted pair, coax or fibre optic cable. The popular cable in use today is category 5 unshielded twisted pair cable and fibre optic cable. Ethernet uses serial signal transmission, one bit at a time. It uses Carrier Sense Multiple Access/Collision Detection (CSMD/CD) topology in which each computer in the network perceives each message but extracts only messages intended for it. Ethernet is adapted to handle collisions in messaging (collision resolution). Collisions occur when two computers send messages at the same time. Design of a MAN from 4 LANs 2.0 Choosing the Network Topology for the LANs We are told that the Steel Works Company operates over an area of approximately 1 square mile with 4 separate non-manufacturing sectors distributed in the 1 square mile region. The table below gives the computers in each section. Section Computers 1 Personnel 5 2 Administration 10 3 Management 8 4 Purchase 12 Basic Assumption The 4 sections are in different buildings and "separated by significant distances" in a 1 square mile space. With this assumption, we have to design a small LAN for each section and then link up the LANS. We choose a Star topology and for uniformity and easy operations, the same: Network Operating Systems, Type of Server Client Operating System We also choose to operate an Ethernet LAN. Each of the LANs will have a Twisted-Pair Ethernet (10BaseT) hub in a star configuration. We use Category 5 terminated cabling. The hub (3Com SuperStack II Hub 10) supports twisted pair, fiber and telco cables. It uses RJ45 connectors. Three of 12-port Hubs needed for 1,2 & 3 and a 24-port hub for 4 below: Section Computers Hubs 1 Personnel 5 1 2 Administration 10 1 3 Management 8 1 4 Purchase 12 1 (24-port) 2.1 Metropolitan Area Networks (MAN) Metropolitan Area Networks are networks that span a campus or city. They usually use wireless or optical fiber connections to link the separate LANs within the campus. For the case study, we shall use MAN technology to link the 4 separate LANs. The LANs can be connected using: Switched Ethernet or 100Base-T . 2.2 Connecting the LANs: Network Equipment-Hardware & Software The following equipment are required in the networking of the LANs and MAN. 1. Network Interface Card (NIC) 2. Category 5 Cables 3. RJ 45 Connectors 4. Hubs 5. Fiber Optic Cables 6. Wireless Communications Equipment 7. Workstations & Servers 8. Operating System Software & Application Systems 2.3 Workstations & Specifications The HP XW 4300 Workstations was chosen as ideal and low-cost, and using the Microsoft XP Operating system. Details of its specifications can be found at the website: http://h10010.www1.hp.com/wwpc/us/en/sm/WF25a/12454-296719-296721-307907-296721-471922.html 2.4 Servers & Specifications The HP PROLIANT ML 150 G2 Server is "designed for workgroups or small-to-medium businesses that need dependable server performance and trusted service and support." Detailed specifications can be found at the website: (http://h10010.www1.hp.com/wwpc/us/en/ss/WF05a/15351-241434-241477-241477-f82-435422.html) 2.5 Network Operating Systems & Specifications The Microsoft Windows 2003 Server has been identified as suitable for each of the 4 workgroups. Detailed specifications can be found at the website: http://www.microsoft.com/windowsserver2003/default.mspx Windows 2003 works well with the HP Proliant ML 150 G2 Server. 2.6 Client Operating System & Specifications The Microsoft Windows XP has been identified as suitable for each of the 4 workgroups. Detailed specifications can be found at the website: http://www.microsoft.com/windowsxp/default.mspx Microsoft Windows XP is the ideal operating system used for the workstation HP XW 4300 chosen above. 2.7 Office Application Software & Specifications The Microsoft Office 2003 has been identified as suitable for each of the 4 workgroups. Detailed specifications can be found at the website: http://www.microsoft.com/office/editions/prodinfo/default.mspx Microsoft Office has the following applications software: Word 2003 for word processing, Access 2003 for database applications; Excel 2003 for spreadsheet applications; PowerPoint 2003 for corporate presentations; Publisher 2003 for business publishing and marketing; Outlook 2003 for personal Information management and Infopath 2003 for productive meetings and automating manual processes. 2.8 Future Trends in Networking.. One of the anticipated "future trends" in networking is called Distributed Computing. This is the ability of working with computers using different Operating systems (OS) each using the services of the other to solve problems. Already it exists but will eventually become as common as word processing. The development of WIMAX technology ( www.wimaxforum.org/technology ) also makes it possible to go beyond Wi-Fi and provide non-line of sight networking of remote locations wirelessly. More than 200 US universities are working with industry and government in a project called Internet2 that is developing and deploying advanced network applications and technologies for research and education, thus accelerating the creation of the Internet of tomorrow. (http://www.internet2.edu/). References Network Topologies http://www.webopedia.com/quick_ref/topologies.asp CISCO Certified Network Associate (CCNA) Study Guide 2nd Ed. Todd Lammle, Sybex, 1999 Komar, B. (1998) Teach Yourself TCP/IP Network Administration in 21 Days, Sams Publishing, USA Dimarzio, J. F. (2002) Teach Yourself CISCO Routers in 21 Days (2nd Edition) Sams Publishing, USA Read More