Understanding Monitor Mode in Network Director
Monitor mode in Network Director provides you visibility into your network status and performance. Network Director monitors its managed devices and maintains the information it collects from the devices in a database. Monitor mode displays this information in easy-to-understand graphs and in tables that you can sort and filter, allowing you to quickly visualize the state of your network, spot trends developing over time, and find important details.
Monitor mode for the Datacenter View displays information specific to the virtual networks, virtual switches, and hosts. To know more about Monitor mode for Datacenter View, see Using Monitor Mode for Virtual Devices.
Monitor mode divides monitoring activity into the following categories:
Traffic—Provides information about traffic on switches, wireless LAN controllers, and interfaces.
Client—Provides session information about clients connected to wireless access points and to 802.1X authenticator switch ports.
RF—Provides information about the wireless environment and signal performance.
Equipment—Provides information about the state of switches, wireless LAN controllers, interfaces, wireless access points, and radios.
Fabric Analysis—Displays the results of running the Run Fabric Analyzer task on a QFabric or Virtual Chassis Fabric (VCF). It shows information about the health, connectivity, and topology of the fabric.
You can access these categories through tabs on the Monitor mode landing page, as shown in Figure 1. An additional tab, the Summary tab, is available that provides a high-level dashboard for the scope selected in the View pane. The monitoring information displayed in the Summary tab also appears on other tabs.
This topic describes:
Scope and Monitor Tab Availability
Your current scope—that is, your view and node selection in the View pane—affects which Monitor tabs are available. For example, if you select a switch, the RF tab is not available.
The shading of the tabs indicate whether a tab is selected, available, or not available:
The currently selected tab has dark text on a light background.
Tabs that are available but not selected have dark text on a dark background.
Tabs that are not available for your current scope have light text on a light background.
When you enter Monitor mode from another mode, the Summary tab is selected for all scopes. If you have selected a tab and then change scope, the tab remains selected if it is supported in the new scope. If it is not supported in the new scope, Network Director selects a default tab for that scope.
Monitors and Tasks
When you click a Monitor tab, the landing page for that tab is displayed, which contains a set of monitors. These monitor enable you to see at a glance important information about the aspect of your network being monitored. For example, the monitors in the Client tab present high-level information about the sessions in the selected scope: the users and client sessions consuming the most bandwidth, the distribution of active sessions by type, and the trend in session count over time.
Detailed information is also available from many monitors when you click the Details icon on the monitor. If the Details icon is not visible in the title bar of a monitor, mouse over the monitor to make it visible. For example, if you click the Details icon from the Current Sessions By Type monitor, you can view detailed information about the current sessions, as shown in Figure 2.
In addition to monitors, each tab provides a set of tasks available from the Tasks pane. These tasks enable you to perform additional monitoring functions. Some tasks enable you to view more specialized monitoring data; others enable you to perform an operation, such as pinging a host. For a complete list of tasks available in Monitor mode, see Understanding the Monitor Mode Tasks Pane.
The scope you select affects which monitors are displayed and which tasks are available. In the Equipment tab, for example, you see a different set of monitors for an EX Series switch than you see for a Wireless LAN controller.
Scope and Data Aggregation
Network Director enables you to monitor one or more devices. It provides a broader network view by aggregating data from devices and making that data available for viewing at higher scopes within the network.
A typical example is RF interference data. Network Director associates RF interference data with the radio that reported it. You can select a radio in the View pane to view the interference data reported by that radio. However, you can also view the RF interference data for the entire wireless network or for a particular location (floor, building, or site). At each of these scopes, Network Director combines or aggregates the data associated with all the radios included in that scope.
Not all data is aggregated at higher scopes. For example, it does not make sense to provide power supply status at any higher scope than the device itself. Whenever monitors are available at a scope higher than the device scope, however, the data presented is aggregated data from all devices contained in that scope.
How Network Director Collects and Displays Monitoring Data
Network Director collects monitoring data from all its managed devices at regular intervals known as polling intervals. These polling intervals can vary according to the type of data being collected. Network Director sets default polling intervals for each type of data—you can, however, change these polling intervals in Preferences.
The polling intervals are aligned to clock time. For example, if the polling interval is set to 5 minutes, then within every hour, Network Director collects data at :00, :05, :10, :15, and so on. If the polling interval is set to 15 minutes, Network Director collects data within every hour at :00, :15, :30, and :45.
Network Director uses the Juniper Networks Device Management Interface (DMI) to the managed devices to collect the data. If you have a Junos Space fabric, Network Director balances the load of polling the managed devices across the nodes in the fabric.
When you display a monitor, the current data is from the last polling interval. Displaying or refreshing a monitor does not trigger Network Director to collect data. However, Network Director automatically refreshes monitors with new data after a polling interval completes. Each monitor displays the time that the data was last refreshed.
The detail windows for monitors are not automatically refreshed after a polling period completes. You must manually refresh them to obtain new polling data.
How Network Director Displays and Stores Trend Data
In addition to displaying current data, Network Director also displays historical data in trend graphs so that you can view trends in network performance over time.
When you display a trend graph, you can select the time period over which the data is displayed—usually 1 hour, 8 hours, 1 day, 1 week, 1 month, 3 months, 6 months, or 1 year. These predefined periods are always relative to the current time and date—that is, if you select a week, the data is from the last 7 days. You can also define a custom time period, which enables you to display data for a period between specific dates and times.
For a trend graph displaying a predefined period of 1 hour, the number of data points depends on the configured polling interval. For periods greater than an hour, the number of data points displayed depends on the time period selected and how Network Director consolidates data over time.
To allow storing of monitoring data for a long period of time, Network Director consolidates older data. Consolidation involves deriving a single value from a set of shorter term values, generally by averaging the shorter term values, and then using that value as a data point in a longer term data set. After the shorter term data is consolidated into longer term data, it is discarded to save storage space. For example, if a value is polled every 5 minutes, the set of 12 values is consolidated into a single value after an hour has passed. That value then becomes one of the 24 data points that makes up the data set for a day. Similarly, after a day has passed, data is consolidated into one data point that represents that day; after a month has passed, data is consolidated into a one data point that represents that month. Data is not kept for more than a year. You can, however, run reports on some monitoring data in Report Mode and archive the reports to maintain a history that is longer than a year.
For all trend graphs, Network Director will not display data until it has more than two data points to display. This means that after you discover a device, trend data will not appear until three polling periods have passed.
More About the Monitor Tabs
The following sections provide more information about each tab in Monitor mode.
The Summary Tab
The Summary tab is displayed whenever you enter Monitor mode. It serves as a high-level dashboard for the current selected scope in the View pane.
The monitors displayed in the Summary tab can belong to any of the Monitor categories. Each scope has a predefined set of monitors that are displayed. For example, if your scope is the Wireless Network, the monitors on the Summary tab summarize the status of wireless equipment in the network, the interference sources in the network, the alarms active on the wireless devices, and the number of sessions in the wireless network.
When you select an individual device in the View pane, the Summary tab itself displays an arrow that indicates whether the device is up (green up arrow) or down (red down arrow).
For the My Network scope, you can customize what monitors appear on Summary tab, giving you the ability to view at a glance those aspects of network health and performance that are most important to you.
The Traffic Tab
The Traffic tab provides information for analyzing traffic on switches and wireless LAN controllers. The four monitors provide an aggregated view of all network traffic on a device, such as proportion of current proportion of multicast, unicast, broadcast traffic or the trend in packet errors. Tasks provide more detailed looks at traffic, such as traffic statistics for individual ports or the degree in which a port’s bandwidth is being used.
The Client Tab
The Client tab provides information about clients and sessions on the network. A client is any device that is connected to the network through a wireless access point or through an access port on a switch that is an 802.1X authenticator port. Examples of clients include VoIP phones, laptops, printers, security cameras, and so on. When a client connects to the network, a session starts, which is uniquely identified by the MAC address of the client.
The Client tab monitors provide a view of overall client session activity in the selected scope. They show the total number of sessions, sessions consuming the most bandwidth, and trends in the number of sessions. Detailed views provide information about each client, such as MAC address, IP address, username, client VLAN, and port or wireless access point the client is connected to. You can also search for a particular client session or sessions using a variety of search criteria and view client history.
Because traffic information is unavailable for sessions connected to access ports on switches, monitors that show session traffic, such as the Top Sessions by MAC Address monitor, are not displayed for scopes that contain switches only.
The RF Tab
The RF tab provides information about the wireless environment and signal performance, allowing you to identify problems that affect wireless connectivity. Monitors provide information about throughput, retransmissions, packet errors, signal-to-noise ratio, and interference sources. Tasks enable you to determine a radio’s neighbors and to display spectrograms for troubleshooting interference.
The Equipment Tab
The Equipment tab provides information about the operational status of individual devices. Monitors display CPU and memory use, power supply and fan status, port status, and general device information for switches and wireless LAN controllers. The status of access point and radios is displayed when you select their wireless LAN controller. Additional information provided by this tab includes the state of logical Ethernet switching interfaces on standalone switches, the topology of Virtual Chassis, and the list of access points that use a selected controller as a secondary controller.
The Fabric Analysis Tab
The Fabric Analysis tab displays the results of running the Fabric Analyzer on a QFabric or Virtual Chassis Fabric (VCF). It shows information about the health, connectivity, and topology of the fabric. For information about analyzing fabrics, see Analyzing QFabric Devices and Analyzing Virtual Chassis Fabrics.