Installation guide

The yellow sections of the MCS chart in figure 32 depict the faster data rates supported by the AP 3600. The
AP3600 supports 802.11a/b/g rates as well as 802.11n rates of MCS values 0−23.
Figure 32  AP 2600 and AP 3600 Supports up to 450 Mbps (MCS rates 0−23)
These additional MCS rates permit more choices for the client supporting 3SSwhen making rate−shifting
decisions because the rate−shifting algorithm maintains the best overall throughput connection.
Clients That Support 3 Spatial Streams
Clients with 3SS support are starting to become commonplace. As the new 802.11ac specification starts to get
traction, many newer client adapters will have the newer chipsets and support 3SS as a subset to 802.11ac.
Additionally, unlike many of Cisco's competitors, the Cisco AP 3600 and AP 2600 fully support all the DFS
channels for more usable channels in the 5 GHz range. More clients, especially 802.11ac clients, will start to
emerge supporting these newer channels in 802.11n modes as well.
Currently, the most popular 3SS client is the Apple 2011 MacBook Pro. It is based on the Broadcom
BCM4331 chipset and a small USB adapter by Trendnet, TEW 684UB, which is based on the Ralink
chipset.
Additionally, the Intel 5300 and 6300 have supported 3SS for a long time. Perhaps because of the different
hardware platforms this card is installed in, testers have observed good throughput on many notebooks (+320
Mbps) and reduced throughput on other notebooks, such as 240 Mbps. If you experience low throughput using
the Intel card, try a MacBook Pro or Trendnet adapter. If these perform well, then try another notebook with
the Intel card. Or, open a case with Intel or the laptop manufacturer for a possible remedy. During the AP
3600 beta trials, differences in performance were observed with different notebooks using the Intel 6300 card.
Note: It can be difficult to reliably maintain a 3SS link because it is easy for the client to rate−shift out of the
3SS mode. The client plays an important role in the ability to maintain a 3SS link, so it can vary with the
quality of the client being used and the test environment.
The AP 3600 with its extra radio per band can use the extra redundant radio to beamform (thanks to
ClientLink 2.0), and uses this to maintain the advantage of 3SS links. Cisco ClientLink 2.0 can also improve
the overall performance of 802.11n clients using 1, 2 and 3 spatial streams and legacy .11a/g clients.