Wireless Throughput Calculations and Limitations
Wireless Throughput Calculations and Limitations
This
article provides details on MR Access Points' advertised maximum data
transfer rates and how they are calculated, including:
- Limitations and factors affecting throughput
- Maximizing throughput
- Testing Client-to-Access Point throughput
- Cisco Meraki Access Point Throughput Rates
Limitations and Factors Affecting Throughput
First
and foremost, throughput to the Internet is capped by the ISP and
devices upstream of the APs. Also, 802.11 is a shared medium and is
limited by other devices connected to the wireless. Therefore throughput
should always be considered aggregate throughput. Interference
(radio, physical, electrical) and the distance from client device to
the Access Point are two major factors that have a negative impact on
observed maximum throughput. Physical obstacles, other wireless networks
and even everyday household devices like computers, microwaves, and televisions increase interference significantly, especially on the 2.4GHz band.
The
half-duplex nature of wireless combined with other overhead also means
that the actual aggregate throughput is typically 50 percent or less of
the data rate. It is theoretically possible for 802.11n-capable wireless
clients to achieve speeds as high as 100Mbps or more depending on the
MIMO capabilities of the AP and the wireless client. However, wireless
clients operating at 802.11b/g/a can cause 802.11n users to slow to less
than 54Mbps because the radio must adjust to the lowest common
denominator.
The
nature of Wi-Fi technology makes throughput hard to predict. Therefore,
network administrators should maintain reasonable expectations for
connection speeds and keep the above factors in mind.
Maximizing Throughput
Optimal
throughput rates and wireless performance in general can be improved by
mounting APs correctly (high up on a wall or on the ceiling).
Additionally, placing APs away from kitchens and other areas with high
interference will also result in better performance. In a mesh
environment, throughput rates will be significantly better with fewer
hops to the gateway.
Meraki
recommends that the end user is located no more than 3 hops away from
the gateway. Each hop will reduce the bandwidth by 50%. For example, a 6
Mbps connection to a gateway will reduce to 3 Mbps at the second hop
and 1.5 Mbps at the third hop.
Testing Client-to-AP Throughput
When testing the throughput of a Cisco Meraki MR Access Point, it is important to remember that any advertised value is the theoretical total maximum data transfer rate (transmit and receive)
for the AP’s radio(s). Device-to-AP speeds should always be tested
using a tool like the Access Point to Client Speed Test available on the
Local Status page, my.meraki.com, under Client survey tools (and
not a tool like speedtest.net). The Access Point to Client Speed Test
tool is especially useful when distinguishing between bandwidth
constraints on the Meraki network (ex. repeater AP to gateway) and
bandwidth constraints of the Internet connection (gateway to Internet).
Cisco Meraki Access Point Throughput Rate Calculations
Please note that the following throughput rates are theoretical for the whole access point, any individual client will be subject to many additional environmental factors that can affect their throughput.
Indoor APs
MR12: Theoretical maximum data transfer rate of 300Mbps
One 2.4GHz radio
Multiple input, multiple output with two spatial streams
150Mbps x 1 radio x 2 streams = 300Mbps
See Datasheet here
MR16/18: Theoretical maximum data transfer rate of 600Mbps
One 2.4GHz radio
One 5GHz radio
Multiple input, multiple output with two spatial streams
150Mbps x 2 radios x 2 streams = 600Mbps
See Datasheet here
MR24/26: Theoretical maximum data transfer rate of 900Mbps
One 2.4GHz radio
One 5GHz radio
Multiple input, multiple output with three spatial streams
150Mbps x 2 radios x 3 streams = 900Mbps
See Datasheet here
MR32: Theoretical maximum data transfer rate of 1170Mbps
One 2.4GHz radio
One 5GHz radio
Multiple input, multiple output with two spatial streams on 80MHz-wide channels
292.5Mbps x 2 radios x 2 streams = 1.2Gbps
See Datasheet here
MR34: Theoretical maximum data transfer rate of 1755 Mbps
One 2.4GHz radio
One 5GHz radio
Multiple input, multiple output with three spatial streams on 80MHz-wide channels
292.5Mbps x 2 radios x 3 streams = 1.75Gbps
See Datasheet here
Outdoor APs
MR62: Theoretical maximum data transfer rate of 300Mbps
One 2.4GHz radio
Multiple input, multiple output with two spatial streams
150Mbps x 1 radio x 2 streams = 300Mbps
See Datasheet here
MR66: Theoretical maximum data transfer rate of 600Mbps
One 2.4GHz radio
One 5GHz radio
Multiple input, multiple output with two spatial streams
150Mbps x 2 radios x 2 streams = 600Mbps
See Datasheet here
MR72: Theoretical maximum data transfer rate of 1170Mbps
One 2.4GHz radio
One 5GHz radio
Multiple input, multiple output with two spatial streams on 80MHz-wide channels
292.5Mbps x 2 radios x 2 streams = 1.2Gbps
See Datasheet here
fonte: https://documentation.meraki.com/MR/WiFi_Basics_and_Best_Practices/Wireless_Throughput_Calculations_and_Limitations
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