Disabling STP support on a router switch port
In some cases, when connecting home clients to the router via wire (TV, NAS, computer, TV set-top box, etc.), you may notice a constant connection loss/recovery on the network port. This may be related to the STP (Spanning Tree Protocol), which is used in Keenetic routers to organise a Mesh Wi-Fi System.
In this case, you can see messages like these in the router's system log (in the example shown, the problem is on port 2
):
[I] 01:08:14 ndm: Network::Interface::Switch: "GigabitEthernet0/1": switch link up at port 2 (1000FD/AN). [I] 01:08:14 kernel: br0: port 1(eth2.1) entered blocking state [I] 01:08:14 kernel: br0: port 1(eth2.1) entered listening state [I] 01:08:17 kernel: br0: port 1(eth2.1) entered learning state [I] 01:08:18 ndm: Network::Interface::Switch: "GigabitEthernet0/1": switch link down at port 2. [I] 01:08:18 kernel: br0: port 1(eth2.1) entered blocking state [I] 01:08:18 kernel: br0: port 1(eth2.1) entered listening state [I] 01:08:21 ndm: Network::Interface::Switch: "GigabitEthernet0/1": switch link up at port 2 (1000FD/AN). [I] 01:08:21 kernel: br0: port 1(eth2.1) entered blocking state [I] 01:08:21 kernel: br0: port 1(eth2.1) entered listening state [I] 01:08:24 kernel: br0: port 1(eth2.1) entered learning state [I] 01:08:27 kernel: br0: port 1(eth2.1) entered forwarding state [I] 01:08:27 kernel: br0: topology change detected, propagating
Starting with KeeneticOS 3.4.1
, the STP protocol has been added to prevent loops. This protocol is used for all wired connections in a Wi-Fi System.
When the topology changes, the STP tree is rebuilt in the built-in switch through the stages of blocking > listening > learning > forwarding.
When a port is brought up from the off state (a network client connects to it), the router has to check if switching it on will cause a loop. To do this, it temporarily blocks communication (entered blocking state
) and examines incoming network packets (entered listening state
and then learning state
). This takes some time, and data transmission through all local ports is blocked for a few seconds. When the router realises it is safe to switch on the port and does not cause a loop, data transmission resumes (entered forwarding state
).
STP triggering can also occur if there are devices on the router's LAN that frequently change the Ethernet connection state (e.g. due to a bad wired connection). Here is an example of a log when there is frequent "twitching
" of the link on port 2
:
[I] 08:43:10 ndm: Network::Interface::Switch: "GigabitEthernet0/1": switch link up at port 2 (1000FD/AN). [I] 08:43:21 ndm: Network::Interface::Switch: "GigabitEthernet0/1": switch link down at port 2. [I] 08:43:23 ndm: Network::Interface::Switch: "GigabitEthernet0/1": switch link up at port 2 (1000FD/AN). [I] 08:43:36 ndm: Network::Interface::Switch: "GigabitEthernet0/1": switch link down at port 2. [I] 08:43:38 ndm: Network::Interface::Switch: "GigabitEthernet0/1": switch link up at port 2 (1000FD/AN). [I] 08:43:50 ndm: Network::Interface::Switch: "GigabitEthernet0/1": switch link down at port 2. [I] 08:43:53 ndm: Network::Interface::Switch: "GigabitEthernet0/1": switch link up at port 2 (1000FD/AN).
This behaviour leads to a rearrangement of the STP topology and, as a consequence, to the disconnection of the link for a short period of time. To avoid such behaviour, you can disable the STP protocol on the network port of the built-in switch to which the end equipment is connected. For this purpose, starting from KeeneticOS 3.5
version, a special command role iseg
has been added.
On the router (Wi-Fi System Controller), through the command-line interface (CLI), execute the role iseg
command so that the router does not react to link changes on the port.
For example, to disable STP on port 2
of the switch, run the commands in sequence:
interface GigabitEthernet0/1 role iseg system configuration save
Önemli
Do not connect
a Keenetic Extender captured in a Wi-Fi System to the port on which the role iseg
command is used, as this will create a loop.