Use the Network Performance dashboard to view performance problems related to network such as high latency, frequent retransmit, and many dropped packets. This dashboard is designed for both the VMware administrator and the Network administrator, to foster a closer collaboration between the two teams.

Design Considerations

To view the common design considerations among all performance management dashboards, see the Performance Dashboards.

The dashboard enables you to drill down from the distributed switch to the ESXi host and port groups in the switch, and then to the VM.

How to Use the Dashboard

  • Distributed Switches.
    • The distributed switches table lists all the switches, sorted by the highest packet dropped. The table splits the incoming traffic and the outgoing traffic for better analysis.
    • As the focus is on performance and not capacity, the throughput counters are not shown.
  • Select a switch from the distributed switches table.
    • The health chart shows the dropped packet trend over time.
    • It does not narrow down the list of port groups automatically, as the list of port groups are always showing all the port groups in your environment.
    • If necessary, expand the two collapsed widgets. They show the network throughput and broadcast packets. Utilization is also shown so that you can correlate and understand whether the dropped packets are due to higher utilization.
  • Port Groups and ESXi Hosts in the selected switch.
    • They get listed when you select a switch from the distributed switches table.
    • Just like the distributed switch, you can also see their relevant counts.
  • If your environment has unused network switches, you can filter them out from this list, as this dashboard focuses only on performance.

Points to Note

  • vSphere network is by nature distributed. Each ESXi contributes to the physical NIC. This represents the physical capacity. Distributed switch and its port groups span across these independent network cards. This makes it harder to define and measure its performance. An unbalance can happen among ESXi hosts or physical NIC. In a sense, it is like distributed storage ( vSAN). Capacity management does not apply to a port group, since its upper limit (also known as the physical capacity) can vary by even a minute.
  • Latency within a data center should be below 1 millisecond. Use vRealize Network Insight to study the latency or the retransmitting problems, caused by moving into the lateral traffic.
  • Add a physical network using the appropriate management pack.

Most packets are unicast, between a pair of sender and receiver. If your environment has many VMs sending broadcast packets to everyone and multicast packets to many targets, add a Top-N widget to find out which VMs are sending these packets.