My simple Network topology: enter image description here

Im trying to figure out what the maximum speed is in mbps on the blue and red links. The exact specs of the wireless networks are these:

  • IEEE 802.11b/g/n, 2.4GHz

Dual omnidirectional internal antennas, 2T2R, 2.8dBi peak gain

  • IEEE 802.15.4, 2.4GHz IPv6

Omnidirectional internal antenna, 2.8dBi peak gain

A) According to this site Speed of IEEE 802.15.4 The max speed of the 802.15.4 standard is 250 Kbit/s. Is that the correct number i am looking for regarding this standard?

B) If the blue links in my topology (connection between Gateway & Access Point) instead of wireless was connected with cable would that then mean that it would have the same max. speed as the gateway (which has a 4g Sim of 50 Mbps in it) ?

C) I just can't find the maximum for the 802.11 standard itself. I can only find the speed of the specific versions ie. 802.11b,g,n etc. My teacher told me those versions were irrelevant since they are device related bottleneck. I am looking for the network speed related bottleneck in general of 802.11.

Hope you guys understand my question.

  • 2
    There is no such thing as "speed of 802.11 in general" It depends on the particular data rate and encoding method, which is specified in subsections a, b, g, n
    – Ron Trunk
    Dec 16, 2019 at 21:01
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    – Ron Maupin
    Nov 19, 2022 at 23:49

1 Answer 1


A) Yes, 802.15.4 has a max. link rate of 250 kbit/s; can't say much about possible effective rates though.

B) Using wired Ethernet 100BASE-TX or 1000BASE-T would support a maximum, effective link speed of 100 Mbit/s or 1 Gbit/s respectively for a maximum of 100 m link reach. It seems overkill for 250 kbit/s edge devices but you won't ever get any congestion between the gateway and the 802.15.4 APs.

C) There's no general maximum speed for IEEE 802.11 as it depends on the protocol variant. 802.11g supports a maximum link rate of 54 Mbit/s, 802.11n of 450 Mbits (depending on the WAP, 150 Mbit/s and 300 Mbit/s are also common). 801.11ax supports up to 9.6 Gbit/s and the upcoming 802.11be is planned for even 40 Gbit/s.

The effective speed is about 50% of that in the best case - wireless network speeds decrease sharply with intermediate obstacles and growing distance. As YLearn has pointed out, there are a few more factors to consider, depending on the planned scenario. Note that in your concept that speed is also shared across all APs, so there's some likelihood of congestion.

  • 1
    802.11n operating as specified in 2.4GHz (unless run as Greenfield) will only operate a 20MHz wide channel and likely using a long guard interval. More realistic data rates are 65/130/195 respectively for 1/2/3 spatial streams.
    – YLearn
    Dec 16, 2019 at 21:27

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