Called a bottleneck, this occurs when the network doesn't handle as much data as usual. A bottleneck is some constraint that limits the rate at which a task can be completed. If a task uses the processor, network, and disk resources, and spends more of its time transferring data to and from the disk, you could have a memory bottleneck. A memory bottleneck might require additional RAM.
Loss of data
If data transfers are incomplete or inaccurate, check to ensure that all network cabling and connectors are intact.
Slow loading of programs and files
Fragmentation (see Tutorial 8, Lesson 2: Hard Disk Drives) occurs when the operating system saves, deletes, and moves information. You must defragment the drive. If slow loading persists even after defragmenting, check for memory bottlenecks.
You must manage software distribution to ensure that users are not loading unlicensed software and computer viruses on the network. One way is to load only software from a centralized location or server and then remotely copy it to local hard disk drives.
A hardware or software failure can bring a LAN to a halt, or the failure can result in more data traffic than the network is designed to handle. You might receive an error message or you might not see any signs other than poor network performance. You must have a system in place that can monitor and manage network traffic. To resolve this problem, you will need to reduce the traffic on the LAN or expand its capabilities.
Common mode failures
Some LAN-component failures affect other components. This is known as a common mode failure. For example, the on-board logic of a NIC might jumble the data format. The NIC will hand the result to the network operating system, which might not detect the error. If the network operating system puts that data into a file, the file will become corrupt.
Every operating system is different, and every customer requires a different level of security. First determine the customer's needs, and then find and read the appropriate documentation.
Maintaining and troubleshooting networks differ according to the operating system. Therefore, you will need to refer to the operating systems' manuals for detailed troubleshooting procedures. A thorough understanding of network troubleshooting is not a requirement of the A+ Certification program. (The section that follows describes some advanced certification programs that focus on networks.) As an A+ technician, you should be familiar with some generic troubleshooting concepts as presented in the following table.