The 802.11ac radio
module for the Cisco Aironet 3600 Series access point
and Cisco Aironet 3700 Series access point provides
enterprise-class reliability and wired-network-like performance. It supports
three spatial streams and 80 MHz-wide channels for a maximum data rate of 1.3
Gbps. This is three times the maximum data rate of today's high-end enterprise
802.11n access point.
The 802.11ac radio in slot 2 is a slave radio for which you can configure specific parameters. Because the 802.11ac is a slave radio, it inherits many properties from the main 802.11a/n radio on slot 1. The parameters that you can configure for the 802.11ac radio are as follows:
Admin status—Interface status of the radio that you can enable or disable. By default, the Admin status is in an enabled state. If you disable 802.11n, the 802.11ac radio is also disabled.
Channel width—You can choose the RF channel width as 20 MHz, 40 MHz, or 80 MHz. If you choose the channel width as 80 MHz, you must enable the 802.11ac mode on the High Throughput page.
The 11ac Supported field is a nonconfigurable parameter that appears for the 802.11ac slave radio in slot 2.
When the Cisco Aironet 3600 Series access point with 802.11ac radio module is in unsupported mode such as Monitor and Sniffer, Admin Status and Channel Width will not be configured.
This section provides instructions to manage 802.11ac devices such as the Cisco Aironet 3600 Series Access Points and Cisco Aironet 3700 Series Access Point on your network.
AP3600 and AP3700 with the 802.11ac module can advertise only the first 8 WLANs on the 5-GHz radios.
Changing the 802.11n
radio channel also changes the 802.11ac channels.
Ensure that your WLAN
has WMM enabled and open or WPA2/AES for 802.11ac to be supported. Otherwise,
the speed of 802.11ac is not available, even on 802.11ac clients.
For more information about the 802.11ac module on the Cisco Aironet 3600 Series access point, see http://www.cisco.com/c/en/us/products/wireless/aironet-3600-series/relevant-interfaces-and-modules.html.
802.11ac Wave 2 and MU-MIMO
The 802.11ac Wave 2 introduces additional capabilities beyond what were added with Wave 1. It utilizes MU-MIMO technology and other advancements to help increase wireless performance for applications such as HD video streaming. Wave 2 provides better RF efficiency that Wave 1 provides, in addition to a number of other features that further improve wireless connectivity.
MU-MIMO is short for Multi-User, Multiple-Input, Multiple-Output. MU-MIMO is an enhanced form of the MIMO technology that enables multiple independent radio terminals to access a system.
With 802.11n or 802.11ac Wave 1, an access point can transmit multiple spatial streams at the same time, but only directed to a single wireless client. This means only a single device gets data at a time. This is referred to as single-user MIMO (SU-MIMO).
802.11ac Wave 2 allows for MU-MIMO, which enables multiple users to simultaneously receive data from the AP simultaneously using the same channel. With MU-MIMO a Wave 2 capable access point is able to use its antenna resources to transmit to multiple clients, all at the same time and over the same channel. MU-MIMO is used in the downstream direction and requires the wireless clients to also be Wave 2 capable.
More Spatial Streams
802.11ac Wave 2 allows for up to eight spatial streams. However, initial Wave2 implementations will only increase the number of spatial streams from 3 to 4 as compared to Wave 1 implementations. The support of an additional spatial stream allows for additional increased performance as compared to 3 SS APs.
For more information on these technologies, see the following documents on Cisco.com:
Explicit Compressed Beamforming Feedback
The AP 1850 supports standards-based Explicit Compressed Beamforming Feedback (ECBF) as defined in the 802.11ac standards. With ECBF the client provides estimates of the wireless channel conditions to the access point. As these are based on explicit channel measurements from the client, both the AP and the client must support it. For 802.11ac, the access point’s ECBF is typically referred to as Transmit Beamforming or TxBF for short.
While both TxBF and ClientLink 3.0 improve the performance of wireless client devices, ClientLink3.0 provides an additional advantage over TxBF. ClientLink3.0 technology does not depend on any client-side hardware or software capabilities and operates seamlessly in mixed-mode environments where 802.11ac and 802.11a/n clients coexist on the same access point. In comparison, TxBF requires client-side support to take advantage of the performance improvements of beamforming and therefore benefits only 802.11ac clients that support TxBF.
The Cisco 1850 AP supports TxBF but not beamforming to legacy client devices. Therefore, Cisco 1850 AP does not support ClientLink 3.0.
ClientLink 3.0 is supported on the Cisco Aironet 2700 and 3700 Series 802.11ac APs.
You can disable TxBF only on the Cisco Aironet 1140, 1260, 1550, and 3500 APs that support ClientLink 1.0. It cannot be disabled on the APs that supports ClientLink 2.0 and above.