Recently, the nature of demands on MANs and WANs has changed dramatically; this is as seen in the Haukland University case study. Previous WAN technologies such as T-lines or X.25, were not complying with the needs of users. Users were expecting higher data rates, lower costs, efficient handling of high data transmissions, and less overhead. In light of this, network technologies that are currently implemented to meet the user’s requirements include frame relay, ATM and Ethernet MANs.
Frame Relay is a virtual-circuit technology the offers low-level services in response to the demands of high data rates at a lesser cost, bursty data, and improved transmission media (Forouzan, 2005, p. 525). In its operation, the frame relay provides constant virtual and switched virtual links. DTEs bond users to the system while the DCEs switches direct the frames through the connection. Therefore, frame relay is normally used as a WAN to connect LANs or mainframe computers. According to Stallings (2005), the advantages of frame relay relevant to its offerings are: 1. it operates at a higher speed (1.544Mbps and recently 44.376Mbps). 2. Because it operates at the data-link and network layers, it can be implemented as a basis network that offers services to a standard that has a network layer. 3. Frame relay offers a variable data rate. Users don’t have to stick to a fixed data rate as in the case of X.25 or T-lines. 4. It allows a frame size of 900 bytes, which can handle all LAN frames. 5. Frame relay is cheaper than other conventional WANs.
For the case of ATM: this is the cell relay standard implemented by the ATM forum and approved by the ITU-T (Stallings, 2005). The user contacts devices, known as endpoints, which are linked through a user-to-network interface (UNI) to the switches within the system. The switches are linked by network-to-network interfaces (NNIs). The data packet for this architecture is a cell composed of 53 bytes, operating for a data rate of up to 100Mbps and in the Gbps range thus eliminating the varying delay times associated with different sized packets. These offerings enable it to support high data rates than frame relay. Secondly, because of its switched nature, the ATM can handle real-time transmissions. Thirdly, the UNI interface increases the network performance and consistency since there is an existence of virtual paths. Thirdly, because of its LAN Emulation (LANE), an ATM switch can behave like a LAN switch. Last but not least, ATM offers enhanced network services since it can use a permanent virtual circuit (PVC) or a switched virtual circuit (SVC).
On the other hand, the Ethernet MAN is a high-speed data connectivity that offers a simple, cost-effective way of networking several stations. It has a data rate of 2- 1000Mbps and enhanced network services. This protocol is designed to use optical fiber. According to Telestra, the characteristics of Ethernet MANs include bandwidth on command, applications such as bandwidth control and schedule manager, effective reporting functionality, and different levels of redundancy. In light of this, the advantages that can be realized from this architecture are: Firstly, there is the flexible and proper use of bandwidth because of a dynamic data access capacity. Secondly, the performance of network components can be monitored easily. And thirdly, Ethernet MAN can be integrated easily into a corporate LAN because of its implementation on the data link layer.
Transition Issues
Replacing a network infrastructure presents an organization like Haukland with several transition issues. Firstly, in its plight to change from frame relay WAN to the Ethernet WAN, the hospital may be susceptible to reduced service delivery to the region. It is known that Haukland University Hospital offers services to Western Region’s 900,000 inhabitants with 200 admissions and 1000 outpatients a day; making a network system changeover would imply that the current day-to-day operations would be compromised. In consideration of this, laying the fiber optic cables for the Ethernet WANs takes a lot of effort and time since the hospital’s region has a diameter of 200km. The hospital may be forced to replace cables with fewer data rates (e.g 100Base-FX) with a high data rate cable (e.g 1000Base-LX) in order to realize the scalability of Ethernet WAN.
Secondly, having a greater data value in the network posses a higher risk in data security. Due to its extensive network, Haukland’s important data such as intellectual property, patient’s information, financial and classified government data are prone to breach. As the new network is implemented, the data that travels through the network must be protected. To ensure data security, Haukland management is faced with a duty of maintaining the availability, integrity and confidentiality of information transmitted in the new network infrastructure.
Thirdly, the implementation costs associated with network configuration and hardware upgrade may be a challenging issue to the Hospital’s management. Since Picture Archiving Communication System (PACS) requires considerable storage and support for a high capacity WAN (Ethernet WAN) the institution will need to upgrade its information systems to support the increased requirements of the network. Devices such as routers may be replaced by Switches.
Therefore, in implementing Ethernet WAN infrastructure the Haukland hospital needs to consider the setup costs associated with this network, security, and the user’s requirements in the welfare perspective; are the customers going to get the best services? And the network should allow for future upgrades.
References
- Forouzan, A. B. (2005). Data Communication and Networking (4th Edition). West Patel Nagar, New Delhi: Tata McGraw-Hill.
- Stallings, W. (2005). Business Data Communications. (5th Edition). Upper Saddle River, NJ: Pearson Prentice Hall.
- Testra.(2009) Ethernet MAN.