Client hops to gateway cut by 50% per hop. Is this true?

[wrainwater]

I didnt realize the wormhole that was opened when I asked  Cisco Tac this. Trying to understand how throughput works heading towards an AP. I was given an article that states the following:

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.

 In our environment, we have an  core switch (gateway lives here) > access switch > 2800 AP > client. By what the article states, that should be 2 hops (access switch to core) which cuts 300 mbps to 150 and again to 75. Is this accurate? Or how does this rule work?

[Jonas Kalldert · Accepted solution]

Hi,

I found the document you refered to:

https://documentation.meraki.com/MR/WiFi_Basics_and_Best_Practices/Wireless_Throughput_Calculations_and_Limitations

The statement is true but it is talking about wireless mesh networks not wired ones.

The gateway in this case is the AP connected to the wired infrastructure not the gateway for the subnet or core.

ex. Client - AP3 - AP2 - AP1 - SW01 - Core. 

So in your case when the client is wireless connected to the AP that is directly connected to the wired infrastructure is not affected by the drawbacks of MESH.

regards,
Jonas
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[omz]

In Meraki world, each wired AP is called gateway and if a Meraki AP is not wired or loses its wired connection, it will try to mesh with another Meraki AP to find its way to Meraki cloud. If successful, it will become a repeater and the AP it will mesh with will be the gateway. On the Meraki dashboard repeater show up as a coloured circle and gateway shows up as coloured dot. 

And yes - each mesh hop will reduce the bandwidth by 50%.

[omz]

You have quoted from Cisco Meraki website but you are using 2800 APs :)

The number of hops is recommended to be limited to three or four primarily to maintain sufficient backhaul throughput, because each mesh access point uses the same radio for transmission and reception of backhaul traffic, which means that throughput is approximately halved over every hop. For example, the maximum throughput for 24 Mbps is approximately 14 Mbps for the first hop, 9 Mbps for the second hop, and 4 Mbps for the third hop.

https://www.cisco.com/c/en/us/td/docs/wireless/technology/mesh/8-6/b_mesh_86/Design_Considerations.html#ID2666

[omz]

Just to add - the throughput being referred is the wireless throughput and not the wired throughput.