Nexus Data Broker - Random devices added to topology

[Matthew Matheus]

An interesting thing is occuring here.  We have about 30 switches attached into a Pair of Nexus 3172 switches running Nexus Data Broker with a Ubuntu controller.  Out of the 30 switches we have connected, Data Broker has decided to add two switches randomly to the topology.  Previously we had an issue with unrelated ARP packets causing devices to be added to the topology, but we've since fixed that.  Does anyone know why a switch would be added to the topology when it's not running the Data Broker software?

[Aliaksandr Tratseuski]

Seems that CNDB (Cisco Nexus Data Broker) uses LLDP data to build the topology. That means if you have any LLDP traffic passing through TAPs which CNDB switch is connected to, corresponding devices will be added to the topology.

As an option to hide unneeded devices is to manually configure flows to drop LLDP traffic on ports which are not supposed to connect to other CNDB switches. However this is not scalable and you miss traffic.