Packet broker is a term used in professional traffic-monitoring tools. Imagine you have a complex campus and a data center network that consists of multiple switches, multiple routing domains, and VRFs. In this network, for any troubleshooting that requires packet capture, you would need to either bring a packet capture device to the local switch--where you need to do the capture--or use remote mirror (span) technologies to send the captured traffic to a packet analysis or monitoring tool.
Nowadays, many monitoring applications require you to set up some sort of packet duplication to appliances for analysis and monitoring. Examples of these are IDS, NAC, application performance monitoring tools, analyzers, and so on.
The following diagram illustrates the SDN monitoring fabric:
A monitoring fabric is a separate network with single or multiple switches. These switches will be connecting to enterprise network using single high bandwidth links (10G...