vpp: T938: Delete 'sample-rate' from vpp sflow CLI and add 'header-bytes'

docs/vpp/configuration/sflow.rst

@@ -10,31 +10,34 @@
 
 VPP Dataplane in VyOS support sFlow for traffic monitoring and analysis.
 
 The VPP Dataplane integration works hand-in-hand with normal kernel sFlow agent, which is responsible for collecting and exporting sFlow samples. VPP itself is responsible for generating the samples.
 
 To enable sFlow in VPP, you first need to configure the service using the same steps as for normal kernel sFlow agent, as described in :doc:`/configuration/system/sflow`. Then you can enable sFlow on VPP interfaces.
 
 Then, you need to enable sFlow on the VPP interfaces you want to monitor. This is done using the following commands:
 
 .. cfgcmd::
 
    set vpp sflow interface <interface-name>
 
 This will enable sFlow on the specified interface. You can repeat this command for each interface you want to monitor.
 
 .. note::
 
    sFlow collects statistics only for traffic *received* on the interface. If you want to monitor traffic *sent* on the interface, you need to enable sFlow on the corresponding interface in the opposite direction.
 
-Optionally, you can specify the sampling rate for the interface using the following command:
+Optionally, you can specify the number of bytes from each packet that should be included in the sFlow sample using the following command:
 
 .. cfgcmd::
 
-   set vpp sflow sample-rate <rate>
+   set vpp sflow header-bytes <bytes>
 
-This will set the sampling rate for the specified interface. The default sampling rate is 1, which means that every packet is sampled. A higher sampling rate means that fewer packets are sampled, which can reduce the amount of data sent to the sFlow collector. This can be useful in high-traffic environments to reduce the load on the collector.
+This defines the size of the packet header (in bytes) captured for each sFlow sample.
+
+The sampling rate is configured globally under the ``system sflow`` section and automatically applied to VPP sFlow.
+This ensures consistent sampling behavior between the system and VPP, and prevents configuration conflicts.
 
 Finally, you need to enable integration between VPP and the kernel sFlow agent using the following command:
 
 .. cfgcmd::