netflow: extend examples

1 files changed, 62 insertions, 5 deletions

diff --git a/docs/system/flowaccounting.rst b/docs/system/flowaccounting.rst
index 1231dcf3..a3ec5248 100644
--- a/docs/system/flowaccounting.rst
+++ b/docs/system/flowaccounting.rst
@@ -1,12 +1,36 @@
 .. _flow-accounting:
 
+NetFlow is a feature that was introduced on Cisco routers around 1996 that
+provides the ability to collect IP network traffic as it enters or exits an
+interface. By analyzing the data provided by NetFlow, a network administrator
+can determine things such as the source and destination of traffic, class of
+service, and the causes of congestion. A typical flow monitoring setup (using
+NetFlow) consists of three main components:
+
+- Flow exporter: aggregates packets into flows and exports flow records towards
+  one or more flow collectors
+
+- Flow collector: responsible for reception, storage and pre-processing of flow
+  data received from a flow exporter
+
+- Analysis application: analyzes received flow data in the context of intrusion
+  detection or traffic profiling, for example
+
+For connectionless protocols as like ICMP and UDP, a flow is considered complete
+once no more packets for this flow appear after configurable timeout.
+
+NetFlow is usually enabled on a per-interface basis to limit load on the router
+components involved in NetFlow, or to limit the amount of NetFlow records
+exported.
+
+VyOS supports flow accounting through NetFlow (version 5, 9 and 10) or sFlow.
 
 Flow Accounting
 ---------------
 
-VyOS supports flow accounting through NetFlow or sFlow.
-
-For both types you need to specify the interfaces for which the data will be collected:
+In order for flow accounting information to be collected and displayed for an
+interface, the interface must be configured for flow accounting. The following
+example shows how to configure ``eth0`` and ``bond3`` for flow accounting.
 
 .. code-block:: sh
 
@@ -15,7 +39,7 @@ For both types you need to specify the interfaces for which the data will be col
 
 
 NetFlow is a protocol originating from Cisco Systems. It works on level3.
-VyOS supports version 1, 5 and 9
+VyOS supports version 5, 9 and 10 (IPFIX - IP Flow Information Export)
 
 NetFlow v5 example:
 
@@ -23,4 +47,37 @@ NetFlow v5 example:
 
   set system flow-accounting netflow engine-id 100
   set system flow-accounting netflow version 5
-  set system flow-accounting netflow server 192.168.2.10 port 2055
\ No newline at end of file
+  set system flow-accounting netflow server 192.168.2.10 port 2055
+
+Displaying Flow Accounting Information
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Once flow accounting is configured on an interfaces it provides the ability to
+display captured network traffic information for all configured interfaces.
+
+The following op-mode command shows flow accounting for eth0.
+
+.. code-block:: sh
+
+  vyos@vyos:~$ show flow-accounting interface eth0
+  flow-accounting for [eth0]
+  Src Addr        Dst Addr        Sport Dport Proto    Packets      Bytes   Flows
+  0.0.0.0         192.0.2.50      811   811     udp       7733     591576       0
+  0.0.0.0         192.0.2.50      811   811     udp       7669     586558       1
+  192.0.2.200     192.0.2.51      56188 22      tcp        586      36504       1
+  192.0.2.99      192.0.2.51      61636 161     udp         46       6313       4
+  192.0.2.99      192.0.2.51      61638 161     udp         42       5364       9
+  192.0.2.99      192.0.2.51      61640 161     udp         42       5111       3
+  192.0.2.200     192.0.2.51      54702 22      tcp         86       4432       1
+  192.0.2.99      192.0.2.51      62509 161     udp         24       3540       1
+  192.0.2.99      192.0.2.51      0     0      icmp         49       2989       8
+  192.0.2.99      192.0.2.51      54667 161     udp         18       2658       1
+  192.0.2.99      192.0.2.51      54996 161     udp         18       2622       1
+  192.0.2.99      192.0.2.51      63708 161     udp         18       2622       1
+  192.0.2.99      192.0.2.51      62111 161     udp         18       2622       1
+  192.0.2.99      192.0.2.51      61646 161     udp         16       1977       4
+  192.0.2.99      192.0.2.51      56038 161     udp         10       1256       1
+  192.0.2.99      192.0.2.51      55570 161     udp          6       1146       1
+  192.0.2.99      192.0.2.51      54599 161     udp          6       1134       1
+  192.0.2.99      192.0.2.51      56304 161     udp          8       1029       1
+