An administrator is troubleshooting intermittent connectivity failures between two workloads connected to NSX VLAN segments using Traceflow. In-band Network Telemetry (INT) has been enabled in the…

Question

Options

• AInjects ICMP traffic into the data plane and observes the results in the control plane.
• BInjects synthetic traffic into the data plane and observes the results in the control plane.
• CTraceflow cannot be enabled to analyze VLAN network segments in NSX.
• DCompares intended network state in the control plane with Tunnel End Point (TEP) keepalives in

• A
  6% (3)
• B
  75% (36)
• C
  4% (2)
• D
  15% (7)

Explanation

In VMware Cloud Foundation (VCF) and NSX, Traceflow is a powerful diagnostic tool designed to provide visibility into the logical and physical path of a packet as it traverses the SDDC. Unlike standard ping or traceroute utilities that use real ICMP traffic from the Guest OS, Traceflow operates by injecting synthetic traffic directly into the data plane at the source point (usually the vNIC of a Virtual Machine). When Traceflow is initiated, the NSX Manager creates a "trace packet" that mimics the characteristics of the traffic being investigated (such as TCP, UDP, or ICMP with specific headers). This synthetic packet is marked with a special metadata tag. As the packet moves through the virtual switches (VDS), logical routers (DR/SR), and distributed firewalls (DFW) on the ESXi Transport Nodes, each component recognizes the tag and reports an "observation" back to the Central Control Plane (CCP). The CCP then aggregates these observations and presents them in the NSX Manager UI. For VLAN-backed segments, Traceflow functions similarly to how it works on Overlay segments. It tracks the packet as it is switched at Layer 2 and processed by any applicable distributed services. The inclusion of In-band Network Telemetry (INT) in modern VCF versions (5.x and 9.0) enhances this by allowing the synthetic packet to collect telemetry data from INT-capable physical switches in the fabric. This provides a "hop-by-hop" view that includes both the virtual and physical segments of the journey.

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