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Too close for comfort

Aruba Employee
Aruba Employee

Did you know 802.11ac’s gigabit data rate requires devices to be very close to the AP?


Newer MCS8 and MCS9 modulations in 802.11ac offer increased performance and require higher signal-to-noise ratios. This means clients must be close to an AP at all times. But isn’t this a basic requirement for any wireless network?


Making sure that clients always associate with an AP with the strongest signal is not as easy as it sounds because clients make their own roaming decisions.


Now don’t go geek and start writing a mobile app that’ll find the closest AP. Chill! Aruba’s patented ClientMatch technology gets rid of the old sticky client problem and lots more.


To see whether this technology makes a difference in roaming, engineers at the testing firm Novarum conducted a high-density roaming evaluation between Aruba and Cisco.


Novarum painstakingly recreated a high-density mobile environment using 75 802.11ac clients and three 3x3:3 802.11ac APs – Cisco 3702i and Aruba AP-225. 


Results from the test clearly show that Aruba offers significantly better roaming performance, thanks to system-level capabilities like ClientMatch. Without it, the network is blind to the needs of its clients.





Help! I’m stuck

According to the test report, clients associated with an AP in a lobby and then roamed to an open space similar to a lecture hall, where clients could hear all the three APs.


As clients roamed, they were distributed pretty evenly across the three Aruba APs. But clients on the Cisco WLAN didn’t associate with a better AP as they roamed. Most got stuck on the first AP.


Screen Shot 2014-06-17 at 1.59.10 PM.png


Aruba ClientMatch was a huge differentiator in this test. It continuously gathers signal information from roaming clients and uses it to steer each one to the closest AP.


Overall system performance

Overall aggregate performance for Aruba was consistently 39%, higher than Cisco. The results are a bit deceiving for Cisco as one client got 120Mbps, which made it’s own roaming decision. All of the other clients struggled for airtime because they were stuck to the first AP.


Screen Shot 2014-06-17 at 1.49.15 PM.png 


Per-client throughput vs. number of clients

With Aruba, most clients enjoyed more than 4 Mbps throughput. With Cisco, more than 70% of the clients got less than 4Mbps. 


Screen Shot 2014-06-17 at 1.50.01 PM.png 


Lesson learned: 802.11ac alone cannot optimize client performance. You need technologies like ClientMatch, which can boost client performance by making sure they associate with the best AP as they roam. And if your clients get stuck, you’re probably using a Cisco AP.


For more detail on the actual testing take a look at the Novarum report or feel free to stop by the Proof of Concept (PoC) lab, Sunnnyvale CA.



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