Virtual Link Group Configuration Guide
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 allow the user to split the traffic into separate groups.
If the Allegro Network Multimeter monitors more than one link, it must differentiate each link. 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 would like to monitor multiple uplinks of a Switch, router or any other network device, you can configure a Mirror Port for each uplink on your Switch. The configure for each mirror port a virtual link Group with just one interface on the Allegro.
If you configure 2 Mirror Ports ( one for rx, one for tx ) on your Switch, include both interfaces on the Allegro for the link group. Once the setup is complete, the Dashboard will show you the traffic per virtual link group.
Use case: Multiple uplinks in-line or tapped
If you have the Allegro in-line for multiple separate links, please configure each virtual link group with the 2 interfaces of link.
Use case: link aggrgation ( LACP,... )
The Allegro can also analyse links multiple links that are aggregated to a big network trunk with LACP or similar. In this case, you can mirror the whole trunk, tap it or even install the Allegro in-line. As 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, please set up a link group with all interfaces for this trunk at the Allegro.
Use Case: Packet broker aggregation
You can use a packet broker to aggregate many links and forward the traffic on one or multiple interfaces to the Allegro. By this method, you can monitor many low-volume links to one interface, like 64x 1G to 1x 10G or 40G. To distinguish the links please configure the packet broker to add a separate VLAN label per link. Then configure this VLAN on the Allegro as a Virtual Link Group.
