Ensuring Network Availability Flashcards
Software that reproduces text input and output for a given command shell or OS
Terminal emulator
Application protocol supporting secure tunneling and remote terminal emulation and file copy. SSH runs over TCP port 22.
Secure Shell (SSH)
Application protocol supporting insecure terminal emulation for remote host management. Runs over TCP port 23.
Telnet
Application protocol for operating remote connections to a host using a graphical interface. The protocol sends screen data from the remote host to the client and transfer mouse and keyboard input from the client to the remote host. It uses TCP port 3389.
Remote Desktop Protocol (RDP)
Application protocol allowing machines to synchronize to the same time clock that runs over UDP port 123.
Network Time Protocol (NTP)
Measurement of a value affecting system performance such as CPU or memory utilization.
Performance Metrics
Troubleshooting issue where performance for a whole network or system is constrained by the performance of a single link, devices or subsystem.
Bottleneck
Establishes the he resource utilization metrics at a point in time such as when system was first installed. This provides a comparison to measure system responsiveness layer.
Performance baseline
Device that can report environmental conditions such as temperature or chassis intrusion to a monitoring system.
Sensor
Application protocol used for monitoring and managing network devices. SNMP works over UDP ports 161 and 162 by default.
Simple Network Management Protocol (SNMP)
Application protocol and event logging format enabling different appliances and software applications to transmit logs or event records to a central server. Syslog works over UDP port 514 by default.
Syslog
Threshold for storing or forwarding an event message based on its severity index or value.
Logging level
Systems that differentiate data passing over the network that can reserve bandwidth for particular applications. A system that cannot guarantee a level of available bandwidth is often described as Class of Service (CoS)
Quality of Service (QoS)
Generally used to refer to the amount of data that can be transferred through a connection over a given period. Bandwidth more properly means the range of frequencies supported by transmission media measured in Hertz.
Bandwidth
The time it takes for a signal to reach the recipient. A video application can support a latency of about 80ms while typical latency on the internet can reach 1000ms at peak times. Latency is a particular problem for 2-way applications such as VoIP and online conferencing.
Latency
