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| Causes for increased CPU load on a WLAN Controller | Solutions |
|---|---|
| The CPU load increases when more Broad- and Multicast packets are sent via a WLC-Tunnel. | In a scenario with a lot of Broad- and Multicast traffic a switch to the mode "LAN at AP" is recommended. |
As of LCOS 10.34 Rel the handling of Broad- and Multicast packets in the LAN bridge was fixed. In earlier Firmware versions no communication between end devices within a WLC-Tunnel was possible, if they were connected to different access points (the total number of Broad- and Multicast packets is derived from the number of Broad- and Multicast packets multiplied with the number of access points which broadcast the SSID associated with a WLAN-Tunnel). This leads to an increased base load of Broad- and Multicast packets in a WLC-Tunnel and thus therefore also to an increased CPU load on the WLAN Controller. | If the scenario was functional up to LCOS 10.34, it could be sufficient to use a virtual WLAN-Controller (vRouter). Depending on the used hardware and assigned ressources for the vRouter VM, this can be significantly more performant than a regular WLAN-Controller. Additionally it is recommended to deactivate the option Allow data traffic between stations of this SSID in the logical WLAN network, if no communication between the end devices is necessary. |
The CPU load increases when more WLC-Tunnels are used. | The number of WLC-Tunnels should be reduced and a WLC-Tunnel should only be used for individual SSIDs, e.g. for the Public Spot SSID. |
The CPU load increases when more end devices are connected via a WLC-Tunnel. | Scenarios with many end devices should be implemented via "LAN at AP" instead of a WLC-Tunnel. |
The CPU load increases when more access points broadcast an SSID via a WLC-Tunnel. | SSIDs with a WLC-Tunnel should only be broadcasted on access points, where this SSID is needed. This SSID should be removed from all other access points. |
If a WLC-Tunnel is linked with a LAN interface via a bridge group, this leads to a greatly increased cpu load. Therefore this has to be avoided at all costs! | |
If a WLC-Tunnel is linked with another WLC-Tunnel via a bridge group, this leads to a greatly increased cpu load and can also lead to complete utilization of the WLAN Controller. Therefore this has to be avoided at all costs! | The use of "LAN at AP" instead of a WLC-Tunnel for such a scenario is mandatory. |
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