docs: add traffic control section

Signed-off-by: Dietmar Maurer <dietmar@proxmox.com>

docs/network-management.rst

@@ -89,3 +89,5 @@ You can also configure DNS settings, from the **DNS** section
 of **Configuration** or by using the ``dns`` subcommand of
 ``proxmox-backup-manager``.
 
+
+.. include:: traffic-control.rst

docs/traffic-control.rst

@@ -0,0 +1,71 @@
+.. _sysadmin_traffic_control:
+
+Traffic Control
+---------------
+
+Proxmox Backup Server allows to limit network traffic for clients
+within specified source networks. The following command adds a traffic
+control rule to limit all clients (network ``0.0.0.0/0``) to 100 MB/s:
+
+
+.. code-block:: console
+
+ # proxmox-backup-manager traffic-control create rule0  --network 0.0.0.0/0 \
+   --rate-in 100000000 --rate-out 100000000 \
+   --comment "Default rate limit (100MB/s) for all clients"
+
+It is possible to restrict rules to certain time frames, for example
+the company office hours:
+
+.. code-block:: console
+
+ # proxmox-backup-manager traffic-control update rule0  \
+   --timeframe "mon..fri 8-12" \
+   --timeframe "mon..fri 14:30-18"
+
+If there are more rules, the server uses the rule with the smaller
+network. For example, we can overwrite the setting for our private
+network (and the server itself) with:
+
+.. code-block:: console
+
+ # proxmox-backup-manager traffic-control create rule1 \
+   --network 192.168.2.0/24 \
+   --network 127.0.0.0/8 \
+   --rate-in 20000000000 --rate-out 20000000000 \
+   --comment "Use 20GB/s for the local network"
+
+.. note:: The behavior is undefined if there are several rules for the same network.
+
+To list the current rules use:
+
+.. code-block:: console
+
+ # proxmox-backup-manager traffic-control list
+ ┌───────┬─────────────┬─────────────┬─────────────────────────┬────────────...─┐
+ │ name  │     rate-in │    rate-out │ network                 │ timeframe  ... │
+ ╞═══════╪═════════════╪═════════════╪═════════════════════════╪════════════...═╡
+ │ rule0 │   100000000 │   100000000 │ ["0.0.0.0/0"]           │ ["mon..fri ... │
+ ├───────┼─────────────┼─────────────┼─────────────────────────┼────────────...─┤
+ │ rule1 │ 20000000000 │ 20000000000 │ ["192.168.2.0/24", ...] │            ... │
+ └───────┴─────────────┴─────────────┴─────────────────────────┴────────────...─┘
+
+Rules can also be removed:
+
+.. code-block:: console
+
+ # proxmox-backup-manager traffic-control remove rule1
+
+
+To show the state (current data rate) of all configured rules use:
+
+.. code-block:: console
+
+  # proxmox-backup-manager traffic-control traffic
+  ┌───────┬─────────┬──────────┐
+  │ name  │ rate-in │ rate-out │
+  ╞═══════╪═════════╪══════════╡
+  │ rule0 │       0 │        0 │
+  ├───────┼─────────┼──────────┤
+  │ rule1 │   10344 │      237 │
+  └───────┴─────────┴──────────┘