5. Interfaces Disaggregation¶
ntopng can split and visualize the traffic into virtual sub-interfaces based on a specified criterion. This comes handy, for example, when a single nProbe instance is capturing flows from multiple NetFlow/sFLow probes. By default, ntopng would aggregate all the probes traffic together into one tcp://… interface, whereas by enabling the disaggregation by “Probe IP” ntopng will also create as many virtual interfaces as the probes, for example tcp://…192.168.0.1 and tcp://…192.168.2.20.
5.1. Dynamic Disaggregation¶
Dynamic Interfaces Disaggregation can be enabled from the network interface configuration tab as depicted in the picture below.
Here is a summary of the available disaggregation criterion:
- None: do not disaggregate
- VLAN Id: create a virtual interface for each VLAN
- Probe IP: on ZMQ, create a virtual interface for each %EXPORTER_IPV4_ADDRESS
- Interface: on ZMQ, create a virtual interface for %INPUT_SNMP and another for %OUTPUT_SNMP. A single flow will be duplicated on two virtual interfaces.
- Ingress Interface: on ZMQ, create a virtual interface for each %INPUT_SNMP
- VRF Id: on ZMQ, create a virtual interface for each %INGRESS_VRFID
Most of them only work in ZMQ mode and require the relevant template field to be added to the nprobe options as explained in the nprobe section.
5.2. Custom Disaggregation¶
In addition to the dynamic disaggregation, it is also possible to use custom BPF-like filters to disaggregate incoming traffic and divert it to logical sub-interfaces. This can be achieved by disabling Dynamic Traffic Disaggregation (setting it to ‘None’) and creating new rules in the Custom Traffic Disaggregation tab. Alternatively you can use both disaggregation methods at the same time, by selecting a Dynamic disaggregation criteria and configuring custom rules at the same time. Custom rules have higher priority: traffic matching custom rules will not be processed by the dynamic disaggregation.
An extended nBPF format is supported when defining sub-interfaces, in fact in addition to the standard BPF primitives, NetFlow fields can also be used, including INPUT_SNMP, OUTPUT_SNMP, SRC_VLAN, DST_VLAN. Note that in this case the same traffic can be diverted to multiple interfaces in case of overlapping filters.
Changes will take effect only after a ntopng restart