The 2 Most Common Misconceptions with Access Points

May 6, 2019 Technology

How many clients can this AP support?

The 2 Most Common Misconceptions with Access PointsThis is probably the question that I receive most often and ironically, it is also my least favorite question to answer. Most who ask this question want to hear a specific number, some absolute maximum. Often, this question is fueled by Wi-Fi manufacturers listing “max clients” on their data sheets and/or this information is relayed directly from one of their representatives.  Naturally, people want to be able to compare capabilities across manufacturers and models.

However, you should never trust any number or range expressed as a “maximum client capacity” without any background or supporting information. For example, many manufacturers list a maximum of 200 clients per radio for an access point. Theoretically, it may be true that a single radio can track up to 200 clients. Unfortunately, the reality is that it depends on many factors and there is no clearly defined answer. It often largely depends on several factors – namely client capabilities, environmental factors, and types of traffic/applications running.

If there are 35 people in a conference room connected to a single radio casually checking email or browsing the web, most access points will work to the user’s expectations. If all 35 users start to stream HD video at the same time, then it wouldn’t be surprising if the network administrator starts to hear complaints about a slow network.

The bottom line is to never trust a number without context.

How fast is it?

This is my second least favorite question because once again there is no straightforward answer. And once again, the industry is to blame for the misconception that there is a speed associated with access point models because companies advertise “speeds” on data sheets and tell their representatives to spew the same information.

Let us start by clarifying the myth of “speed” listed for any access point model. The speed that they list actually refers to the aggregate data rates of both radios at their theoretical maximum rate. So, for an 802.11n access point, the maximum data rate for the 2.4GHz radio is likely about 200Mbps and the 5GHz is about 450Mbps. It is not unusual to see the data sheet list the “speed” at a misleading 650Mbps.

Another problem with concentrating on the “speed” of the access point is that we put on blinders to the fact that wireless infrastructure is used by wireless clients. If a new 802.11ax access point were installed with theoretical speeds of 2.4Gbps that would be fantastic! However, if all you have are 802.11g clients in your environment—then you haven’t improved wireless communication at all. When it comes to Wi-Fi, you are only as strong as your weakest connection.

The biggest problem with the industry’s response to this question is that it’s only in reference to a single downstream link from the AP to the client. Obviously, this does not reflect the reality and expectations of users, because what really counts is throughput. Throughput is the actual amount of data that passes or is processed through a system. In terms of Wi-Fi, throughput is the actual amount of payload data sent/received wirelessly between a client and the access point. Throughput is always less than the data rate or speed.

The best advice I can offer is to never accept the answer to either of these questions without digging deeper into the context and details of the current environment.

 

Alex ZeltmannAlex attended the Cisco Academy during his time in high school and joined the ABS team during his senior year in 2005 as an intern. Alex went on to attend Virginia Tech and graduated with a B.S. in Computer Science while still working for ABS during his school breaks. Upon graduation, Alex became a full-time employee in 2010 and has worked his way all the way up to his current role as the Infrastructure Engineer Manager.