What does 1750mbps really mean?

Discussion in 'Networking, Telephony & Internet' started by DVDHack, Feb 8, 2019.

  1. DVDHack

    DVDHack Member

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    ive been looking at a few APs and when I look at the specs it talks about 2G with 450Mbps and 5G with 1300Mbps, so a combined bandwidth of 1750Mbps. What confuses me is how that’s actually possible with a 1Gbps Ethernet interface? Does this mean that in mesh systems it will realise high throughput?
     
  2. bcann

    bcann Member

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    Marketing BS....

    For the most part expect between 20-40MB/sec if your the only one on the wifi connection. otherwise its shared bandwidth and given the only real speed is on the 5GHZ spectrum, unless your close to the AP, you'll never ever see 1300Mb. My laptop is 2 walls from my ubiquity AP, and i regularly get 30MB/sec from it but not much more.

    ALso like you've pointed out the limiting real factor is the Ethernet port is only 1Gb/sec, but you'll likely never ever flood that ethernet link.
     
  3. xc351

    xc351 Member

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    exacly that the wifi can transfer at a max of 1300Mbs this is over all devices on that feq. Tribands generally have 2 x 5ghz radios.

    There will be alot of overheads but yes good wifi is the speed of 1Gbs+ but its unlikey 1 device will get that speed. plus its not as stable ect.
     
  4. chip

    chip Member

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    It's marketing for '"we added up all the numbers, including counting in both directions, in such a way that it gives an impressively large number"

    If gigabit ethernet manufacturers has a similarly flexible approach, that 1000BASE-T interface would magically become a "2000Mbit" one.
     
  5. elvis

    elvis Old school old fool

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    FWIW, 802.3bz aims to solve the "we need more than 1Gbit/s to the AP" problem:
    https://en.wikipedia.org/wiki/2.5GBASE-T_and_5GBASE-T

    Not a super popular spec at the moment, but with 10GbE ports appearing on mainstream motherboards and 802.11ac Wave 2 here and 802.11ax / "WiFi 6" around the corner, we'll see it start to creep into the consumer space soon.

    The only constant is change.
     
  6. xc351

    xc351 Member

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    Your right and using the same theory you 8 port switch would be 8000Mbit
     
  7. Copie

    Copie Member

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    Would be 16000Mbit.
     
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  8. elvis

    elvis Old school old fool

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    Well, switch manufacturers do advertise backplane speeds to give you an understanding of how the switch will perform at maximum capacity. You'll often find enterprise switches with the same number of ports at the same port speed where one model has a higher capacity backplane, and will sell for more than the lower model.

    That, and a Wireless AP functions more like a hub, so the number does matter when you hit congestion.
     
  9. OP
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    DVDHack

    DVDHack Member

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    In the scenario where I’m using the 1750Mbps AP as the main backbone supporting one or more stations in a mesh environment, will the this unit give me better throughout and is it worth the cost?

    My scenario is the Pro unit will be located at the house and be connected to the main switch and will form the base station for a couple of other on two sheds on my farm. The sheds will have a couple of IP cameras on them and will be monitored from the house.
     
  10. wintermute000

    wintermute000 Member

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    WIfi throughput is a combination of following:
    - Channel width
    - Modulation achieved
    - the PHY rate (or raw rate) achieved
    - number of radio streams

    Marketing is usually total BS assuming things like ridiculous channel width (80Mhz or even 160Mhz which is often not as practical as 40Mhz IRL unless you're on a farm as effective throughput would get murdered due to co-channel interference, campus deployments you ALWAYS use 40 or 20 esp hi-density), textbook modulation and PHY because you're sitting under the WAP directly, 3x or even 4x radio streams when most laptops have 2x, etc. Then there's Wave-2 where maximum throughput is only achieved to MULTIPLE clients (hence MU-MIMO) so the figure is nonsense for single figures

    And yes, 2.5Gb/5Gb is a thing in enterprise, most people are 'future proofing' now and high-end campus switching from 2017 onwards have started carrying a subset of 2.5Gb/5Gb ports (mGig or 802.3bz) ports. With wave 1 there is absolutely no need, wave 2 you could exceed 1Gb in non ridiculous situations if you had multiple wave-2 MIMO compatible clients downstream in favourable conditions and had a RF plan that allowed for 40mhz or wider channels.

    Skim the tables here you will get an idea of what I'm talking about.

    https://www.cisco.com/c/en/us/solut...rks/802-11ac-solution/q-and-a-c67-734152.html

    Mesh is a different ball game, but the big boys have multiple radio for say backhaul on 5 and clients on 2. I'm not a wireless specialist. If you're not a networker and you don't want to get balls deep into this stuff do consider a dedicated mesh solution like Ubiquiti Unfi Mesh if you want something business grade or even the consumer mesh products as it will make your life a heck of a lot easier. HOWEVER sounds like you're not really talking about mesh but rather just extending the reach of your WLAN? In that case you're just talking about repeaters.

    If you want max performance you WILL have to do a site survey and work out what frequencies are present where and what the RF will look like.
     
    Last edited: Feb 9, 2019
  11. OP
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    DVDHack

    DVDHack Member

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    I am actually on a farm, think I said above, I’m looking to get cameras and some other functions out to remote sheds to protect machinery and run pumps etc. I don’t have any interference issues here.

    I already run Ubiquiti gear, I have their APs in the house and have an external unit running my fodder production unit. I’m currently assessing the AP Mesh Pro, which has the 1750Mbps as my main station and I already have the smaller AP AC mesh unit as the first station to the main unit I’m assessing, currently using that as the main unit. I’m running Ubiquiti cameras and have just ordered the new Cloud Key 2 version that combines the NVR. I also have a pair of nano 5m units which I’m trying out to just make a bridge to the main camera deployment area. There’s a bunch of options I’m trying. I was hoping the Mesh Pro would utilise the excess bandwidth to avoid the bandwidth loss from the repeater function in the mesh network.
     
  12. wintermute000

    wintermute000 Member

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    OK so took a glance at the datasheet and it appears to be a AC wave-1 device if you're talking about
    https://dl.ubnt.com/datasheets/unifi/UniFi_AC_Mesh_DS.pdf

    The 1300 figure means row 23 here @ 80Mhz channel width with 256-QAM 5/6 modulation and 3 spatial streams. So that's lab conditions. Unfortunately it doesn't look like dual radio (note: it is dual band, so same radio/antenna can handle 2.4 or 5). Ideally with mesh you'd want one radio on backhaul and one on access, on non-overlapping channels (duh) taking into account your channel width (80Mhz = more slots used up obviously).

    http://mcsindex.com/

    FWIW using 80Mhz on my Wave-1 at home I get around ~55Mb/sec sitting right next to the WAP with a 2 spatial stream laptop. I CBF to see if switching to 40Mhz will get me a better IRL result or doing a survey, I'm in a regular suburban house and one AP on defaults works fine lol.

    So go for it unless you can afford Wave-2 or dual radio, and definitely go for broke with channel width, you might even get away with 160Mhz, just don't overlap the (combined) channels. I'm not sure if Ubiquiti will auto-magically sort out the RF like that, I stay far away from the deets/implementation for WLAN lol.... here is a good example (not specifically mesh, but you get the drift)

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

    Final nitpick, 2.4 actually has better range than 5, so it might actually work better for some parts of your property, again you'd need to actually do a site survey to be sure
     
    Last edited: Feb 9, 2019
  13. OP
    OP
    DVDHack

    DVDHack Member

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    Thanks for all the help. I’ll setup the Nano link when the brackets get here and deploy the cameras. If that’s OK then I can probably get away with the mesh unit and an outdoor M2 unit I have to cover the other functions. If the cameras aren’t effective over the link I’ll order the Mesh Pro unit. The Pro is twice the price of the standard mesh units, hence the questioning of the specs.

    I do like the UniFi gear, I like the way you can label everything and really get in to what’s going on on the network. It’s also really easy to monitor everything and keep all the units updated. My main 24 port PoE switch however is really noisy.
     

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