US Patent 10908941 Timestamping data received by monitoring system in NFV

A network traffic monitoring system is provided. The system includes a host computer executing a plurality of virtual machines (VMs), including a monitoring VM and a virtual switch (vSwitch). The vSwitch includes a plurality of virtual Network Interface Cards (vNICs) associated with the plurality of VMs. The monitoring VM is coupled to the vSwitch and executed by the host computer. The vSwitch is configured to mirror a plurality of data packets exchanged between two communicating VMs to a vNIC associated with the monitoring VM. The monitoring VM is configured to retrieve the plurality of mirrored data packets from the vNIC associated with the monitoring VM. The monitoring VM is further configured to generate timestamps indicative of packet arrival time at the vSwitch for each data packet in the retrieved plurality based, at least in part, on a computed base time.