Virtual Link Group functionality

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The Allegro Network Multimeter allows for defining up to 100 so called Virtual Link Groups (VLG) to logically separate traffic for easier analysis.


All statistics data for each Virtual Link Group (VLG) are strictly separated. Once at least one VLG is defined, a drop-down menu appears at the top menu bar allowing to select which VLG should be chosen for the displayed statistics.

Packet capture also takes the VLG into account so when capturing a specific IP for example, the system only returns packets for that IP in the currently selected VLG. Expert capture filters still allows to use multiple VLG filter for a single capture or disable the VLG filter at all (by not using the 'group' filter).

Statistics for a VLG can also be reset independently from other VLGs (since firmware version 4.2). The drop-down menu contains an trash bin button to reset the measurement statistics for that VLG.

Virtual Link Group selector.png


Virtual Link Group settings.png

The groups can be selected in the web interface in the top menu bar. The configuration can be performed in the settings section.

The following criteria can be used for defining groups:

  • Interface IDs
  • VLAN tags
  • MPLS labels
  • WiFi BSS
  • Tunnel Source (Firmware >= 4.3.0)

In case of VXLAN, please make sure that Tunnel View Mode is active. Only in this mode VXLANs are analysed and its VNI can be used for VLGs.

Virtual Link Group add interfaces.png Virtual Link Group add vlan.png Virtual Link Group add mpls.png Virtual Link Group add erspan.png Virtual Link Group add tunnel source ip.png
Interface IDs VLAN tags MPLS labels ERSPAN ID Tunnel Source

A group can contain several entries of the same criterion that form an OR connection. Different criteria form an AND connection. E.g. it is possible to define a group with interface id 3 or id 4 and VLAN tag 400. Don’t forget to push the add button when configuring entries of a criterion.

A group can be set active or inactive.

It is also possible to limit the detail of traffic analysis for each group individually. Similar to the Global settings it allows to let one group be analysed only to layer 3, for example, and for another group full analysis is done. This will improve performance and increase the data storage time.

The group definition can be exported and imported via in a CSV file by using the "Download CSV" and "Import CSV buttons in the settings page".

Once a group is defined or changed it will be applied on new packets only. Older packets will not be grouped into a new group. To avoid confusion, it is recommended to restart the processing (see Settings).

A packet can only be part of one group. It will be grouped into the first group whose definition matches. The grouping will be applied in the same order as shown in the group list in the web interface. You can use the up and down buttons in the settings section to change that order.

All statistics in the Allegro Network Multimeter will show information related to the selected group only. Interface graphs, total traffic graph on the dashboard and the burst analysis module will, however, show global information and ignore the group selection.

Traffic color settings

A group can be configured so that all traffic counters are displayed in a utilization color.

Traffic values below medium will be displayed in green, values above medium will be displayed in yellow and value above high will be displayed in red.

Virtual Link Group dashboard.png

The thresholds for medium and high can be configured in Mbit/s.

The default settings are

  • medium 800 Mbit/s
  • high 950 Mbit/s
Virtual Link Group traffic add color settings.png

Detail of traffic analysis

Each virtual link group can limit the detail of traffic analysis to a specific network layer. Reducing the detail will improve overall performance and increase the history time. In contrast to the Global settings for the detail of traffic analysis, this option still allows for some groups to show more detailed information while for other only limited data is available.

NOTE: The configuration can be changed during runtime, but it is recommended to do a processing restart so statistics for already running connections are not mixed between different groups and processing modes.

Virtual Link Group functionality processing mode

Statistics timeout

Since firmware 4.2, the age of the measurement statistics can be configured individually for each Virtual Link Group separately.

The configuration dialog allows to enter an arbitrary duration for which the data should be stored. The value can be in plain seconds, or with d/h/m suffixes also in days (d), hours (h), or minutes (m).

The global timeout is used if no value is entered (or zero). Data can also not be older than the global timeout.

Virtual Link Group functionality statistics timeout