Factors that impact network performance / Elements of Ethernet/802.3 networks

Factors that impact network performance 
4.1.2 This page will describe some factors that cause LANs to become congested and overburdened. In addition to a large number of network users, several other factors have combined to test the limits of traditional LANs:

• The multitasking environment present in current desktop operating systems such as Windows, Unix/Linux, and Mac OS X allows for simultaneous network transactions. This increased capability has lead to an increased demand for network resources.
• The use of network intensive applications such as the World Wide Web has increased. Client/server applications allow administrators to centralize information and make it easier to maintain and protect information.
• Client/server applications do not require workstations to maintain information or provide hard disk space to store it. Given the cost benefit of client/server applications, such applications are likely to become even more widely used in the future.

The next page will discuss Ethernet networks.

Elements of Ethernet/802.3 networks 

4.1.3 This page will describe some factors that can have a negative impact on the performance of an Ethernet network.

Ethernet is a broadcast transmission technology. Therefore network devices such as computers, printers, and file servers communicate with one another over a shared network medium. The performance of a shared medium Ethernet/802.3 LAN can be negatively affected by several factors:

• The data frame delivery of Ethernet/802.3 LANs is of a broadcast nature.
• The carrier sense multiple access/collision detect (CSMA/CD) method allows only one station to transmit at a time.
• Multimedia applications with higher bandwidth demand such as video and the Internet, coupled with the broadcast nature of Ethernet, can create network congestion.
• Normal latency occurs as frames travel across the network medium and through network devices.

Ethernet uses CSMA/CD and can support fast transmission rates. Fast Ethernet, or 100BASE-T, provides transmission speeds up to 100 Mbps. Gigabit Ethernet provides transmission speeds up to 1000 Mbps and 10-Gigabit Ethernet provides transmission speeds up to 10,000 Mbps. The goal of Ethernet is to provide a best-effort delivery service and allow all devices on the shared medium to transmit on an equal basis. Collisions are a natural occurrence on Ethernet networks and can become a major problem.  
The next page will describe half-duplex networks.