Live Traffic Analysis (LTA) provides helpful insight about tracing live traffic and bi-directional packet tracing. Traffic analysis monitors live traffic at a source or between source and destination along with the packet capture. You can identify bad flows between the source and the destination. If the packet counter of the certain flow at the source endpoint is much higher than the packet counter of the certain flow at the destination endpoint, packet drop may occur between two endpoints. Hence the flow is probably a bad flow which you can trace for further analysis. Thus traffic analysis is helpful in troubleshooting virtual network issues. You can find the number of packet enter or leave a port, and the unexpected packet drop.
Limitations
- LTA supports only on the overlay-backed NSX environments.
- LTA is not supported on DPU.
- LTA is not supported on T0 Active/Active setup.
- LTA is not supported on Global Manager.
- LTA cannot observe VMware Cloud components that do not belong to the NSX management domain, such as IGW.
Enhancements
- LTA session supports count action for ENS fastpath. For more information, see the NSX API Guide.
- LTA session supports datapath statistics action. To specify this action, set the actions property to
datapath_stats_config
in the following NSX API:PUT https://<nsx-mgr>/policy/api/v1/infra/livetraces/<livetrace-id>
For more information about this API, see the NSX API Guide.
- Examples:
-
The following API creates an LTA session request on a source port with datapath statistics action.
PUT https://<nsx-mgr>/policy/api/v1/infra/livetraces/<livetrace-id> { "src_port_path" : "/infra/segments/InfraSegment101/ports/default:066b6ef4-3f5e-4fb4-b6df-751c006a4a50", "filter" : { "ip_info" : { "src_ip" : "192.168.1.10/32", "dst_ip" : "192.168.2.10/32" }, "resource_type" : "FieldsFilterData" }, "actions" : { "datapath_stats_config" : { "trace_type" : "UNI_DIRECTIONAL" } }, "timeout" : 10 }
The following API retrieves the details of an LTA session result.
GET https://<nsx-mgr>/policy/api/v1/infra/livetraces/<livetrace-id>/result
Performance Impact
When the LTA count action is enabled on ENS fastpath, it may cause a performance impact on the network. The performance impact observed while using LTA is a reduction of approximately 7% ~ 20% range in PPS and MBPS rates.
Listing some of the scenarios where the performance impact might be observed:
- Traffic inside the ESXi host: This refers to the traffic that is contained within a single ESXi host, where communication occurs between VMs running on the same hypervisor.
- Traffic across the ESXi host: This refers to the traffic that moves between VMs on different hypervisors (ESXis), and the traffic traverses not only within each VM but also through the physical NIC (pNIC) of each hypervisor.
- DFW is enabled along with LTA: This refers to the case where LTA and DFW are enabled at the same time, meaning that both features are active and working together.
Create a Session
To start a LTA session, click New session. For details, see Create a Live Traffic Analysis Session.
Session List
Status | Description |
---|---|
In Progress | The session is collecting the results. Wait for the session to finish. |
Realized | Realized session is that session whose intent configuration is realized on the management plane. |
Unrealized | Unrealized session is that session whose intent configuration is yet to be realized on management plane. |
Partial Finished | Only partial session result is available. Some session results might have lost. |
Finished | After the session is finished, you can view the session for further analysis. You can also rerun, duplicate, or delete the session. |
Cancelled | The session is canceled by exception. |
Invalidated | The session is canceled proactively by the data plane service because of disconnection of the source port or the data plane service is down. Make sure that the source or destination port is not migrated or disconnected during the running LTA session and retry. |
Timeout | The session is timed out. |
To view the latest status, click the Refresh icon. To perform the following tasks, click and then click the required option.
Option | Description |
---|---|
Rerun | Run an existing session again. The session persists only for one hour. |
Delete | Delete an existing session. |
Copy Path to Clipboard | Get the path of the LTA configuration. You can use the copied path later. You can filter the LTA sessions using the copied path. |
Session Details
Observations Tab | Description |
---|---|
Delivered | Total number of received observations for the traceflow round. |
Dropped | Total number of dropped observations for the traceflow round. |
Physical Hop Count | The sequence number is the traceflow observation hop count. The hop count for observations on the transport node that a traceflow packet is injected in can be 0. The hop count is incremented each time a subsequent transport node receives the traceflow packet. The sequence number of 999 indicates that the hop count could not be determined for the containing observation. |
Observation Type | The observation type can be Forwarded, Dropped, Delivered, Received, and Injected. |
Transport Node | The name of the transport node that observed a traceflow packet. |
Component | The name of the component that issued the observation. |
Actions | You can view details for certain traceflow observation like MAC details of a logical switch or segment. |
Packet Count Tab | Description |
---|---|
Component | The type of the component. |
Transport Node | ID of the transport node that observed a traceflow packet. |
Packets Received, Forwarded, and Dropped | Number of traceflow packets that were received, forwarded, or dropped. |