148 CHAPTER 9 Network Management to a location on the local hard drive or a network server. In other cases, the system will provide a specific tool for viewing the information. Password lists Password lists should contain all the passwords used to perform administrative or maintenance tasks on the network. This includes passwords for Administrative and administrator account for servers and workstations. Setup and configuration utilities on computers and other devices. Administrative features in software. Files, such as those containing other passwords or documentation containing procedures. Notification documentation Notification documentation includes contact information for specific people in an organization, their roles, and when they should be called. The contact information included in notification doc- umentation should provide several methods of contacting the appropriate person. Notification procedures should also include contact information for certain outside parties who are contracted to support specific systems. Network Performance Optimization Network performance optimization is the process of assessing the network's status on an ongoing basis by monitoring and discovering network traffic and logs. Pos- sible monitoring targets include the following: data rates, available bandwidth, WAN link status, backup time, device response rate, and component failures. The methods in which we will use to discover performance issues may include the following: Crunch Time Quality of Service (QoS) is a measure of value of a net- work service compared with the expected or the predicted performance quality that network service is actually pro- ducing on your network. QoS can assist in mitigating issues, such as "jitter." Applications like Voice over IP (VoIP) cannot be used effectively if jitter is excessive. Errors ­ Sometimes packets are misdirected, or combined together, or corrupted, while en route. QoS protocols include the following: Dropped packets ­ Some, none, or all of the pack- ets might be dropped, depending on the state of the network, and it is impossible to determine what will happen in advance. Delay/Latency ­ Overcrowded data links on routers in the transit path of your packets could result in a delay of data packets. Long queues or indirect route avoiding congestion might be some causes of latency within your network. Jitter ­ When there are delays in transit, some packets leaving after others might arrive at the des- tination first. This variation in packet delay is called Resource Reservation Protocol Multiprotocol label switching QoS models include the following: Differentiated services (DiffServ) specifies a way of classifying and managing network traffic on IP networks. Integrated services (IntServ) allows applications to signal associated QoS requirements to the local network before transmitting information. There are eight levels of QoS as described in Table 9.1.