A

Active Directory
Also known as AD. A directory service that provides central authentication and authorization for Windows computers. Allows network administrators to group users and computers, assign policies, etc.

Agent
Agents are the tools that report the status and performance of individual computers to PerformanceGuard. You must install an agent on each computer that you want to monitor.

Agent configuration group
The behavior of PerformanceGuard agents is controlled by agent configuration groups. Each agent configuration group controls a number of agents. An agent can only be a member of one agent configuration group, and each agent will be associated with exactly one configuration. PerformanceGuard administrators manage agent configuration groups in the PerformanceGuard web interface.

Alert
When events occur based on threshold violations, they can make PerformanceGuard automatically generate an alert. The alert can in turn make PerformanceGuard automatically generate a notification that's sent via e-mail and/or displayed on the location dashboard in the PerformanceGuard web interface.

API
Application Programming Interface, a set of building blocks that together provide an interface for consultants, software developers and other technical audiences who need to access collected performance data and manage PerformanceGuard entities.

Application dashboard
Part of the PerformanceGuard web interface that lets you view the status of important applications in your organization. If applications don't perform on an acceptable level, the application dashboard shows you the extent to which your organization is affected. It also lets you drill down to see exactly which subnets and computers are affected.

Application ping
A PerformanceGuard feature that lets you measure the availability of servers and services. Also able to do traceroutes and measure latency and response times.

B

Backend server
Important PerformanceGuard component. Receives data from PerformanceGuard frontend servers. Aggregates data and deletes old data as required. Has a notification module that can automatically send e-mail notifications to selected recipients. Requires a SQL database for storing data. Runs as a service; that is it runs in the background without a user interface.

BTM
Business Transaction Monitoring, a PerformanceGuard feature that lets you monitor complex work tasks that involve multiple steps and/or multiple servers. With BTM, you can define when a task begins and ends, and thereby measure how much time it takes for users to complete specific tasks. BTM can help you identify process bottlenecks in your organization.

C

Citrix
A virtual computing environment that lets users run Windows applications from a remote server just as if the applications were running on users' own computers. From a management point of view, this has the benefit that the applications can be controlled and maintained centrally. Citrix is quite common for running enterprise software in corporate environments.

Collector
Old name for a PerformanceGuard frontend server.

Context switch
A context switch is the process of storing and restoring the state of a process so that execution can be resumed from the same point at a later time. Simply put, if a computer has a lot of context switches, it needs to remember a lot of states, and that can affect its performance negatively.

Custom counter
With the PerformanceGuard custom counmter feature you can collect data from any Windows performance counter, and use the data when you monitor performance in PerformanceGuard. PerformanceGuard has a tool that helps you quickly set up custom counters with the right syntax.

D

Display
Old name for the PerformanceGuard web interface.

E

Event
An event is something that has happened on an individual computer or server. In performance measurement, events typically relate to a threshold value that is violated so that performance is no longer considered acceptable. PerformanceGuard can automatically inform you of occurred events on dashboards in the PerformanceGuard web interface or through e-mail notifications.

F

Frontend server
Important PerformanceGuard component. Receives and processes performance data from PerformanceGuard agents before the data is sent on to the PerformanceGuard backend server. Requires a SQL database for storing data. Runs as a service; that is it runs in the background without a user interface. Can be installed on more than one server to distribute load. If so, each frontend server requires a separate SQL database.

H

HTTP filter
A type of PerformanceGuard transaction filter for monitoring the performance of web activities. HTTP filters are monitored directly on the data packets collected on the monitored network interface (NIC).

I

IE filter
Internet Explorer filter, a type of PerformanceGuard transaction filter for monitoring the performance of web activities.

IO
Also known as I/O. Short for Input/Output.

K

KPI
Key Performance Indicator, a quantifiable measure that an organization can use to gauge and compare performance, such as the ability to meet a defined goal.PerformanceGuard has KPI reporting features that you can use to keep stakeholders informed about your IT organization's ability to live up to defined goals and targets.

L

LLMNR
Link-Local Multicast Name Resolution, a protocol used for multicast (that is sending of a single set of data packets across a network to multiple subscribing users at the same time). LLMNR uses the multicast IP address 224.0.0.252 and UDP port 5355.

Location
Locations are logical containers used for making it easy to navigate performance data. In PerformanceGuard you can set up a hierarchy of locations, and then associate those locations with your organization's networks in order to offer intuitive navigation of performance data. This is useful, because most users prefer to view performance data based on geographical locations that they are familiar with (example: the London office) rather than based on technical network structures that may not mean much to them (example: subnet 192.168.101.155/24).

Location dashboard
Part of the PerformanceGuard web interface that provides a quick overview of the status of your organization's locations and computers. For each location you can quickly view the number of users online, the number of occurred events (that is performance threshold violations) and the number of users affected by the events. Also lets you view further location details and reports.

M

Monitored port/server
PerformanceGuard automatically detects every server and port that computers with PerformanceGuard agents communicate with. However, computers may communicate with thousands of servers and ports, but only a subset of those servers and ports are typically relevant. That's why PerformanceGuard lets you select servers and ports that are relevant for you to keep an eye on: these are called monitored servers and monitored ports.

Multicast
Sending of a single set of data packets across a network to multiple subscribing users at the same time.

N

Network group
PerformanceGuard automatically groups computers that belong to the same subnet into the same group, called a network group. Network groups are dynamic: If a computer moves to another subnet, PerformanceGuard automatically moves the computer to the corresponding network group. If a matching network group does not already exist, PerformanceGuard automatically creates one. Only PerformanceGuard can place computers in network groups; nobody else can do that, not even administrators. However, administrators can configure network grouping rules that'll determine how PerformanceGuard places computers in network groups.

Notification
When events (that is threshold violations) happen, they can make PerformanceGuard automatically generate an alert. The alert can in turn make PerformanceGuard automatically generate a notification that's sent via e-mail and/or displayed on the location dashboard in the PerformanceGuard web interface.

Notification framework
Old name for a PerformanceGuard backend server.

P

Ping
A utility for determining the availability of an IP address. Ping sends a data packet to the required IP address and records the time it takes to get a reply. The name ping is believed to come from the sound made by a sonar.

Port
A logical endpoint for data traffic. Networks use different ports for different types of data traffic. Most ports are used automatically based on the types of data included in the communication. On TCP/IP networks, port numbers range from 0 to 65536, but only ports 0 to 1024 are reserved for particular purposes. For example, port 80 is used for HTTP traffic, which is what you typically use when you view web pages.

Process
An instance of a computer program that's being executed. A process can be related to a program that you can see run on your computer screen, but it can also be an invisible internal process that the computer goes through, for example during startup.

R

Report
1) A document that describes findings and data. PerformanceGuard offers multiple different reports that can be generated manually or generated and distributed automatically. 2) Collected performance data sent by a PerformanceGuard agent to a PerformanceGuard frontend server is also known as a report.

REST
REpresentational State Transfer, a simple stateless web interface that uses XML and HTTP. REST basically lets you request information from one system so that you can use it in another system. PerformanceGuard has a REST-based API that you can use to work with performance data on other platforms.

Retransmission
Automatic resending of data packets that did not reach their destination, or arrived in a damaged state.

RTO
Retransmission Timeout. Retransmissions timeouts are bad because they slow down traffic. RTOs occur when senders get too few acknowledgments from receivers and therefore decide to break for a short moment before they attempt to send data again. Once the senders begin sending data again, they do it with a slow start (first two data packets, then four, and so on), and this can lead to delays in traffic.

RTT
Round-Trip Time. In TCP network traffic, RTT is the length of time it takes for a client to send a request plus the length of time it takes for an acknowledgment from the server to be received by the client. RTT does therefore not include the time it takes for server applications to respond, or the time required for data transfer.

S

SLA
Service Level Agreement. A part of a service contract where particular aspects of a service, such as availability, response times, etc. are defined. The SLA features in PerformanceGuard can help you verify whether you and/or your service partners live up to SLAs.

Slow start
When a TCP connection is established, the sender carefully tests the capacity of the network and the receiver by first sending only two packets of data. If that goes well, the sender sends four packets, and so on. The benefit of this is that TCP will ideally not send more data than the network and the receiver is able to handle. The downside is that it takes a while before a TCP connection is working at its full capacity. If slow starts only happen when connections are established, they're generally not a problem. However, if connections often time out and have to be re-established, slow starts can be a great problem, because it takes time for the connection to get up to speed again each time it is re-established.

SSDP
Simple Service Discovery Protocol, a protocol used for multicast (that is sending of a single set of data packets across a network to multiple subscribing users at the same time). SSDP uses the multicast IP address 239.255.255.250 and UDP port 1900.

SSL
Secure Sockets Layer, a protocol for transmitting data via the internet in encrypted form.

SSO
Single Sign-On, the ability to log in once and get access to several independent systems.

Subnet
Subnets (short for subnetworks) are separate, smaller parts of an organization's network. You typically use subnets to logically group all computers at a particular geographical location, a department, an office, or similar. All computers on a subnet share the same first part of their IP addresses. It's very common to divide a network into subnets, because it can improve network performance as well as security.

Super group
Logical container that helps you organize the groups of computers you have in PerformanceGuard, typically network groups. A super group is simply a group of groups. In PerformanceGuard, super groups to a large extent serve the same purpose as locations, but unlike locations you can't view super groups dashboards—super groups are only administrative containers.

T

TCP
Transmission Control Protocol, a connection-oriented protocol for data traffic that lets data be sent bidirectionally. TCP uses flow and congestion control, reception acknowledgements, error checking, etc. to ensure that transferred data packets remain intact and arrive in the same order in which they were sent. TCP is thus highly reliable, but can be slower and use more resources than the more simple alternative, the UDP protocol.

Traceroute
A method for detecting and capturing the paths that data packets travel from a given starting point to a specific destination. Also records the network latency between different routers along the route to the final destination. PerformanceGuard has features for collecting and presenting traceroute information.

Train
A train is a number of data packets that flow in one direction without any packets flowing in the other direction. Looking at sent and received trains can be useful when you analyze performance, for example in order to identify missing responses or services that cause excessive amounts of trains to be sent.

Transaction filter
A PerformanceGuard feature for classifying web requests and extracting information from those requests. A web page typically consists of multiple elements. With a transaction filter you can measure the total time it takes to render the full web page on an end user's computer.

TSL
Transport Security Layer, a protocol that's used to transmit data via the internet in encrypted form.

U

UDP
User Datagram Protocol, a simple connectionless protocol for data traffic. Unlike the more advanced TCP protocol, UDP has no features for verifying reception, connection reliability, correct data order, etc. However, UDP is fast and lightweight. UDP can thus be suitable for applications that need quick—but not necessarily reliable—data transmission, for example games or servers that need to answer large amounts of small queries from large numbers of clients.

Utilization index
In PerformanceGuard, a utilization index is an interactive graph that lets you compare memory usage, CPU usage, disk usage, etc. over time on selected computers. Utilization index data is based on 15-minute intervals.

W

Web interface
The PerformanceGuard user interface with which you can view computer and network performance, generate reports, etc. Administrators can also use the web interface to configure PerformanceGuard, including the PerformanceGuard agents.