2. During the 1980s, organizations began to install local area networks to connect computers in departments and workgroups. Department-level managers usually made decisions about what type of computers and networks they wanted to install. Eventually, organizations saw benefits in building enterprise networks that would let people throughout the organization exchange e-mail and work together using collaborative software. An enterprise network would connect all the isolated departmental or workgroup networks into an intracompany network, with the potential for allowing all computer users in a company to access any data or computing resource. It would provide interoperability among autonomous and heterogeneous systems and have the eventual goal of reducing the number of communication protocols in use. Toward this goal, industry organizations were formed to create open standards, and vendors developed their own strategies.
3. An enterprise network is both local and wide area in scope. It integrates all the systems within an organization, whether they are Windows computers, Apple Macintoshes, UNIX workstations, minicomputers, or mainframes. An enterprise network can be thought of as a "plug-and-play" platform for connecting many different computing devices. In this platform scenario, no user or group is an island. All systems can potentially communicate with all other systems while maintaining reasonable performance, security, and reliability.
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6. The main attributes of the enterprise network are these: Quality of service (QoS). The network is designed, configured, and managed with QoS as its keystone. This means that traffic is classified at the source and prioritized end-to-end through an infrastructure that requires nothing of its users outside their normal method of operation. The ideal network is an extension of its applications and remains invisible to the users except for the jack in the wall. Standards-based. Recognizing that no single vendor can provide all the elements of the enterprise network, the design and structure are based on open standards. This does not preclude the use of equipment with proprietary elements, but cross-platform and cross-product interoperability are required. Furthermore, purchases, including those made with departmental budgets, must conform to the company’s equipment and application standards.
7. Security. The network is designed, configured, and managed with security and server protection paramount. It integrates both wired and wireless components and is designed to detect and prevent intrusion at the edge and to survive attacks without service interruption. Policies and procedures such as sanitizing files and applications are conveyed to users to protect the network core. Reliability. Fault tolerance is designed into the network. Components are manufactured to high standards of performance and are hot swappable. Management announces and adheres to service-level agreements (SLAs) that give the users assurance that mission-critical applications will not experience unscheduled downtime. Asset and investment protection. Existing equipment is applied for maximum benefit. Duplicate infrastructures are avoided by adapting to new applications and new technologies without major changes or upgrades.
8. PRIVATE DATA NETWORKS The main attraction of connection-oriented services such as frame relay as a platform for private networks is the lack of concern about security. The Internet has spawned a type of data network known in the trade as a VPN, referred to here as a data VPN to distinguish it from a voice VPN. A VPN is a set of sites that communicate with one another over a public IP network while maintaining the security and management capabilities of a dedicated circuit or frame relay network. The basic functions of a VPN are membership discovery—who belongs to what VPN and the establishment of a secure tunnel through the network.
9. VPN subscribers have the following objectives for the network: Security. The VPN is secure from unauthorized access to the same degree as a network implemented over frame relay or dedicated circuits. Connectivity. Any authorized site can use IP’s connectionless capability to connect to other sites. New sites can be added quickly. Mobile users can access the network from remote locations. Also, the network can span multiple service providers where necessary. Simplicity. The network is easy to set up and manage. Resiliency. The network can respond rapidly to changing traffic patterns. Scalability. The network can scale to meet changing needs as the subscriber adds locations or connects to external users such as customers and business partners. Quality. The VPN can support multiple media including voice, video, and multicast with sufficient QoS. The service provider offers and adheres to SLAs based on worst-case scenarios as opposed to averages.
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11. A VPN consists of a combination of authentication, tunneling, access control, and encryption that is designed to carry data securely over a public network. A network tunnel is a metaphor for the process of encapsulating the data of one protocol inside the data field of another protocol.
12. Thank you J.TC08D712 B.Nyamdavaa J.TC08D006 G.Azbayar
