In a mobile environment, power save is an important feature for end clients. Meraki employs a number of standards-based power save mechanisms, as detailed below.
PS-Poll is a legacy power save mechanism defined in the 802.11 spec. This mechanism allows the client to indicate to the AP that it is going to sleep until the next beacon. The AP buffers frames while asleep, then lets the client know that frames are buffered via an advertisement in the beacon. All Meraki Access Points support PS-Poll.
Unscheduled Automatic Power Save Delivery (U-APSD) is a QoS facility defined in IEEE 802.11e that extends the battery life of mobile clients. In addition to extending battery life, this feature reduces the latency of traffic flow delivered over the wireless media. Because U-APSD does not require the client to poll each individual packet buffered at the access point, it allows delivery of multiple downlink packets by sending a single uplink trigger packet. U-APSD is enabled automatically when WMM/QoS is enabled.
The following table describes which Meraki APs support U-APSD:
|802.11n||MR18, MR24, MR26|
|802.11ac / Wave 2||All 802.11ac and 802.11ac Wave 2 platforms|
The BSS Max Idle period is the maximum time frame a client can be idle (no frames received by the AP) before the AP disassociates the client. This ensures that the client device does not send keep-alive messages frequently, which drains battery power. The idle period timer value is transmitted using the association and re-association response frame from the AP to the client. The idle time value indicates the maximum time a client can remain idle without transmitting any frame to an AP. As a result, the clients remain in sleep mode for a longer duration without transmitting the keep-alive messages, thereby saving battery power.
The BSS max idle period is enabled by default on all Meraki APs.