Virtual Link Group Configuration Guide

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About

The Virtual Link Group allows to group traffic in virtual links on the Allegro Network Multimeter. By default, the Allegro aggregates all traffic on all interfaces and the ingress interface makes no difference to the analytics. The Virtual Link Group allows the user to split the traffic into separate groups.

If the Allegro Network Multimeter monitors more than one link, it must differentiate each one. If, for example, one packet is seen on each link, it is NOT a retransmission. If it is seen twice on the same link, it is a retransmission.

Configuration

Check the wiki manual for a detailed description Virtual Link Group functionality.

Note that each packet will be assigned to the first matching Virtual Link Group. To avoid double accounting of packets, each packet can be only part of ONE Link Group. If you need to group overlapping groups, use the IP module IP Groups option.

Use case: Multiple uplinks mirroring with multiple mirror ports

If you need to monitor multiple uplinks of a Switch, router or any other network device, you can configure a Mirror Port for each uplink on the Switch. Then configure a Virtual Link Group for each Mirror Port with just one interface on the Allegro.

Virtual link setup mirror.png

If you configure 2 Mirror Ports ( one for rx, one for tx ) on the Switch, include both interfaces on the Allegro for the Link Group. Once the setup is complete, the Dashboard will display the traffic per Virtual Link Group.

Use case: Multiple uplinks inline or Tapped

If the Allegro is installed inline for multiple separate links, configure each Virtual Link Group with 2 link interfaces.

Virtual link setup link.png

Use case: Link aggregation( LACP,... )

The Allegro can analyze multiple links which are aggregated in a large capacity network trunk with LACP or similar. In this case, you can mirror the whole trunk, Tap it or install the Allegro inline. Since all packets belong to one link, you do not need to set up a Virtual Link Group. If you connect other links to the Allegro, set up a Link Group with all interfaces for this trunk on the Allegro.

Use Case: Packet Broker aggregation

You can use a Packet Broker to aggregate multiple links and forward the traffic on one or multiple interfaces to the Allegro. Using this method, you can monitor many low-throughput links to one interface, such as 64x 1G to 1x 10G or 40G. To distinguish the links, configure a Packet Broker to add a separate VLAN label per link. Then configure this VLAN on the Allegro as a Virtual Link Group.

Virtual link setup vlan.png