There are multiple scenarios in which traceflow is useful.

Traceflow is useful in the following scenarios:
  • Troubleshooting network failures to see the exact path that traffic takes
  • Performance monitoring to see link utilization
  • Network planning to see how a network will behave when it is in production

Prerequisites

  • Traceflow operations require communication among vCenter, NSX Manager, the NSX Controller cluster and the netcpa user world agents on the hosts.
  • For Traceflow to work as expected, make sure that the controller cluster is connected and in healthy state.

Procedure

  1. In the vSphere Web Client, navigate to Networking & Security > Tools > Traceflow.
  2. Select the traffic type: Unicast, Multicast, or L2 Broadcast.
  3. Select the source VM vNIC.
    If the VM is managed in the same vCenter Server where you are running the traceflow, you can select the VM and vNIC from a list.
    Note: When a logical switch is in multicast replication mode, the VMs connected to this logical switch will not be listed and cannot be chosen as the traceflow source or destination.
  4. For a unicast traceflow, enter the destination vNIC information.

    The destination can be a vNIC of any device in the NSX overlay or underlay, such as a host, a VM, a logical router, or an edge services gateway. If the destination is a VM that is running VMware Tools and is managed in the same vCenter Server from which you are running the traceflow, you can select the VM and vNIC from a list.

    Otherwise, you must enter the destination IP address (and the MAC address for a unicast Layer 2 traceflow). You can gather this information from the device itself in the device console or in an SSH session. For example, if it is a Linux VM, you can get its IP and MAC address by running the ifconfig command in the Linux terminal. For a logical router or edge services gateway, you can gather the information from the show interface CLI command.

  5. For a multicast traceflow, enter the multicast group address.

    The packet is switched based on MAC address only.

    Both the source and destination IP addresses are required to make the IP packet valid. In the case of multicast, the MAC address is deduced from the IP address.

  6. For a Layer 2 broadcast traceflow, enter the subnet prefix length.

    The packet is switched based on MAC address only. The destination MAC address is FF:FF:FF:FF:FF:FF.

    Both the source and destination IP addresses are required to make the IP packet valid for firewall inspection.

  7. Configure other required and optional settings.
  8. Click Trace.