Introduction
Information technology has the potential of revolutionizing service provision in all sectors of the economy. Many people continue to loose their jobs as others create new ones because of advances in information technology. The email has taken over the role of conventional mail. There have been libraries since time immemorial. They have lasted for centuries on end. Until the last few years, there has never been the need to improve information and retrieval systems.
The process of digitization has forced many institutions to find ways and means of making their material available in digital formats. Many authors release two sets of books, print versions, and digital versions. This has made it necessary for libraries to create infrastructure that enables them to keep on providing their essential services using digital technologies. This paper relates to the architecture required to develop a communication network for a county library. It considers both human and technical aspects necessary for the process.
Concept of Operations
General Operations of a County Library
The information technology explosion witnessed in the last twenty years is responsible for changing the way organizations provide services to clients. The process of computerization of institutions has brought about great efficiency in service provision in both the public and the private sector. Public libraries are some of the institutions whose service provision has benefitted from information technology.
Public libraries such as county libraries provide a wide array of services to the public. These services revolve around lending of information-based resources. These resources may be in print or electronic formats. Academic resources provided include books, journals, and periodical publications from diverse places. Students and faculty visit the libraries to get access to these resources.
Other print resources found in a county library include magazines, encyclopedias, and newspapers. The advantage that public libraries have over private ones is their diverse nature of content and the long history they have increasing the likelihood of finding unique resources from different historical settings. Libraries have systems that take care of the functions they have. These systems include reference systems for the resources they have and a borrowing and tracking mechanism. They require registration to enable them maintain a database of members who access the resources.
Description of the Network
Hardware and Software
A network is necessary for the provision of computerized services in a public library. It refers to the interconnected devices that form the electronic environment for the services. All networks have hardware and software components. Hardware components refer to all the physical components that provide the physical interconnection required to access the services offered by a county library. On the other hand, software components provide the platform required to run the programs that form the basis of the electronic services. They dictate storage methods, retrieval mechanism, and access procedures. They also deal with network security issues.
Uses of the Network
The network under design will provide several services to the county library. These services include enabling direct access to electronic resources, provision of ordinary library services, internal and external communication via a web link and a bulletin board service that will allow for the development of an online forum for various user groups who have similar interests.
The trend internationally in the provision of library services point towards digitization of resources to increase access and availability. To make these resources available to as many users as possible, it is necessary to use a network. A network expands availability because it allows multiple accesses from remote locations. The network under design will make it possible for the library members to access these resources without having to wait, as may be the case in print-based information. The network will also enhance the provision of normal library services such as registration of new members, booking of resources, tracking of resources and information sharing.
The network will leverage on the effort to computerize the library and make the provision of services less time consuming. In addition, the network will make it possible for the library to provide services online to members. This will reduce the demand for location-based services since members will be able to request for services and access some of them from remote locations via the internet. The fourth benefit this network will provide to the library is that it will enhance the operations of the interest groups in the library via a bulletin board. The network will provide a forum for interaction among various individuals with a common interest.
The Networks User Applications
The specific uses of the network will include a search function, resource booking, access to electronic resources, and internet access. One of the key elements of accessing library resources is the knowledge of where to find a desired resource. Before the advent of computers, libraries depended on index catalogues classified by author and by subject. In the Google-age, it is no longer necessary to keep catalogues. Libraries have unique resources and developing a network makes it possible for users to search through the digital databases faster and more efficiently. In this library, it will eliminate the need for catalogues, and will make it possible to include more fields than a single catalogue card can hold.
The next advantage the network will provide is that it will make it possible for users to access electronic resources from the library. A network multiplies the points of access, such that a user will not need to queue or to be on a waiting list to access resources. The final service that the network will provide will be access to the internet. In some areas in the world, the only internet access point available for the public is in public libraries.
Requirements
The network under design will require a number of elements. This includes the physical architecture and the protocol architecture of the network. These two elements will have detailed treatment in subsequent sections. In addition, it will have user training needs and maintenance requirements. After set up, users will need training on how to take advantage of the new infrastructural outlay provided by the library. Shifting from manual based systems to IT based systems normally call for careful introduction and training before the new services catch on. It is wise to have a transition period where service provision still relies in the old method while implementing the new method. This allows for time for all key user groups to familiarize themselves with the new technologies and compare their experiences.
Stakeholder acceptance is crucial for the success of the shift. The transition period also provides time to deal with bugs as the users interact with the system. The final switch comes in when a critical mass of users is comfortable using the network.
There is a specific need to have a resident technician for routine maintenance tasks. After the design and installation of the system, the technician will provide technical support to ensure the system does not fail over minor technical glitches. The whole maintenance of the network may be out-sourced such that the service provider also provides day-to-day maintenance of the system. However, the library will find it more cost effective to retain an internal technician to manage the system and to take care of minor problems, since retaining the services of a technical company for the same task will mean higher expenses. However, a contract will still be necessary for routine maintenance functions and system upgrades.
Physical architecture
The physical architecture of the network is the visible part of the system. The critical components of the system include PC’s, Network Interface Cards (NIC), routers, switches, and hubs. They also include firewalls and Intrusion detection devices. Other network related infrastructure includes LAN cables, Storage Area Network (SAN) and Network Attached Storage (NAS).
PC’s
The PC’s are the basic input and output devices in the physical network. A PC can do its processing and storage, and it supports information retrieval. However, it is only when it is part of a network that it is useful as a device for accessing remote information. In the network under design, users will interact with the library’s electronic resources from PC’s located in the library or remotely via an online link.
Network Interface Cards (NIC)
NIC’s provide the means through which PC’s connect to the network. It configures communication to and from the individual PC’s enabling communication with other PC’s and network devices. These cards may be inbuilt on a PC, or be acquired as a separate units. For this project, the inbuilt version will provide lesser operational hassles; hence will be the first choice.
Switches, Routers and Hubs
Switches routers and hubs will be intermediaries in the network connections. They will establish communication channels within the network. The LAN cables connect the PC to the network via these devices. The type of cables used with them varies. They can be Ethernet, Serial, or USB. In the library’s design, preference is for Ethernet cables because of ease of system maintenance when using Ethernet cables. Routers will also be preferred over switches and hubs because of the greater flexibility they offer a network such as the ability to run firewalls.
LAN Cables
Within the library, LAN cables will be the means of interconnecting all PC’s that constitute the network. Outside the library, the networks will depend on the type of access remote users have to the internet. Strictly speaking, remote users do not constitute the primary user group considered under the network under design. However, the network design will fully consider their needs since the network will have the remote communication capabilities via an internet link. The LAN cables will connect all the computers that constitute the system within the library.
Physical Network Topologies
The system architecture for the library will have a choice of five network topologies, which are, bus, ring, star, point to point and point to multipoint topologies. The bus topology refers to the linking of all PC’s using a single wire. All the PC’s ‘hear’ what is communicated over the wire in this configuration. The ring topology connects PC’s using “paired physical interfaces” (InetDaemon) which have a clockwise and anticlockwise connection. PC’s in the network use a “token-passing scheme in which the computer holding the token is allowed to transmit” (InetDaemon). The Star topology is the most common topology in use today whereby all the PC’s and other network devices connect to a common hub or repeater (InetDaemon).
They form a pattern that is radiating outwards in the shape of an asterisk. The Hub and Spoke topology is another way of referring to the Star topology. Point to point topology applies when there are only two devices in the network. The two devices share a single hardware connection that no other device shares. The point to multipoint topology refers to a connection where all devices connect to a particular device through a single connection.
Recommendation for Library System
The recommendation for the library design is the Star topology. Its major advantage is ease of expansion. It will allow users who come to the library with their laptops to connect very easily to the network. The internet connection will use the point to multipoint network. This means that PC’s in the network will utilize a single internet connection under a client and server configuration.
Protocol Architecture
The physical architecture prepares the networking effort for the second phase of the network design. Protocol architecture represents the second section of the network design. It describes the ‘language’ of communication between different devices.
Protocol Models
The two most important protocol models are the TCI/IP Model and the Open Systems Interconnection (OSI) Network Model.
TCP/IP Model
The TCP/IP Model, also known as the DOD model because the United States Department of defense designed is the model upon which the internet runs. Its other name is the DARPA model. Many organizations also use TCP/IP because they find it flexible and it provides a great degree of functionality. The TCP/ IP protocol architecture consists of four layers. They are the Application Layer, the Transport Layer, the Internet Layer, and the Network Interface Layer. Several sub protocols exist under each layer. They ensure the execution of specific functions.
Network Interface layer: This function of this layer’s is the placement place and retrieval of TCP/IP packets on the network. This function relies on the cross network compatibility of the TCP/IP model. It operates independent of the network, giving it applicability in new networks.
Internet Layer: This layer is responsible for, “addressing, packaging and routing functions” (Microsoft). It has four protocols under it. They are. “Internet Protocol (IP), the Address Resolution Protocol (ARP), Internet Control Message Protocol (ICMP), and the Internet Group Management Protocol (IGMP)” (Microsoft).
Application Layer: Also known as the “Host-to-Host Transport Layer”, the application layer, it provides the application layer with “session and datagram communication services” (Microsoft). Under it, there are two protocols, the Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP).
Application Layer: This layer provides other layers with access to services from the other layers and identifies protocols that they will use to exchange data (Microsoft). Many application layer protocols exist, and the creation of many more is ongoing. The most common ones in use include Hypertext Transfer Protocol (HTTP), File Transfer Protocol (FTP) and the Simple Mail Transfer Protocol (SMTP) (Microsoft).
Open Systems Interconnection (OSI) Model
The International Standards Organization (ISO) developed the Open Systems Interconnection (OSI) model. Unlike the TCP/IP model, it has seven layers. “Each layer in the TCP/IP Model corresponds to one or more layers in the OSI model” (Microsoft).
Application Layer: This layer provides the environment for the user application to interact.
Presentation Layer: It prepares data for use either by the network or for user applications depending on source and destination.
Session Layer: It is the custodian of session-related issues such as when the session starts and when it ends.
The above three layers correspond to the Application Layer of the TCP/IP model
Transport Layer: It ensures correct sequencing of data packets and undertakes error correction.
Network Layer: It finds the best path available for each type of communication and then it directs the data in the best direction possible.
The Data link Layer and Physical Layer corresponds to the Network Interface Layer in the TCP/IP model.
Data-link Layer: This layer is responsible for putting “data into frames and ensures error free transmission” (The Computer Technology Documentation Project). It is also responsible for keeping time during network transmissions.
Physical Layer: This layer represents the actual hardware in the network.
PDU Structures
Within each of the layers, there is a distinct way of referring to the data. Under the OSI Model, each of the layers has a Protocol Data Unit (PDU). The first layer has its Protocol Data Unit as the bit. The frame is the Protocol Data Unit for the second layer, the Data Link Layer. The Protocol Data Unit for the third layer, which is the Network Layer, is the packet. In the fourth layer, the protocol data unit is the segment. This fourth layer is the transport layer. All the layers from the fifth one have data as the Protocol Data Unit
Physical Layer Considerations
As the layer is made up of the physical devices such as the PC’s, and other network equipment, some specific considerations apply.
Signal Type
There are two signal types available for use by the library in its network. The library may use optical signal or electrical signal. Each of the signal types has its advantages and its drawbacks. Optical signals require the use of fiber optic cables and are very useful for long distance transmission. They also have little resistance. They are however more expensive than the alternative. Using electrical signals makes sense in the library’s network. The distances involve is not large to make fiber optic cabling competitive.
Data Rate
The data rate requirements for the network will be moderate since traffic within and without the library will be moderate. However, the larger the data rate capacity, the better because with a large data rate capacity, the library will not need to expand its infrastructure within a short time. This is because more and more applications keep cropping up, thereby wiping away the existing capacity.
Link distance
The link distance for communications will depend on external factors when users in the library seek to connect to the internet from the library. However, it will be an important issue when users in remote locations access materials hosted in the library’s servers. To keep the link distance at a minimum, the arrangement of the digital files in the server will matter.
Works Cited
InetDaemon. InetDaemon: Real Training for Internet Professionals. 2011. Web.
Microsoft. TCP/IP Protocol Architecture. 2011. Web.
The Computer Technology Documentation Project. Network Layers. 2011. Web.