Do multiple repeaters slow the network down?

Discussion in 'Mac OS X Server, Xserve, and Networking' started by HyperX13, Jan 5, 2012.

  1. HyperX13 macrumors 6502

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    #1
    I have Airport Extreme and then 7 Airport Expresses, all set top extend network. My speeds are kind of pathetic. About 1.5 megs for transfers, the signal is great. My same setup at work, where I do not have repeaters, gives me 5-6 meg transfers with same Macbook pro.

    So I wonder if having too many Airport Expresses doing network extension is the culprit? Anyone?
     
  2. willieva macrumors 6502

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    Mar 12, 2010
    #2
    Having the network extended will slow things down. If the transfers you're talking about are to/from the outside world, then it might have more to do with your internet connection speed. If you can plug into your router and try it you would be able to see whether the slowdown is due to your network configuration.
     
  3. BiggAW macrumors 68020

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    #3
    You lose 1/2 of the bandwidth on the first repeat, not sure after that. If you have that many wireless AP's, you either need better wireless gear, or a wired backbone. If you own your dwelling, Ethernet is the best, if not, homeplug would probably be a good second choice.
     
  4. cwaddell2002 macrumors member

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    #4
    Yes - that will significantly affect your speed. How many square feet are you trying to cover with that many wireless devices? Are there a lot of other wireless networks around? You could improve your speed by replacing some of the expresses with better wireless repeaters with higher gain antennas and reduce the number you need. That said, wired backbone is the way to go if at all possible.....
     
  5. HyperX13 thread starter macrumors 6502

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    #5
    My home is 4000 sq foot. Its wooden. The airport extreme will not reach everywhere, so I have it extended. I will try turning some repeaters off. Thanks!
     
  6. Alrescha macrumors 68020

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    #6
    This.

    Multiple *wired* Airport Expresses all configured alike (except for channel) will cover your house will no speed degradation.

    A.
     
  7. Gav2k macrumors G3

    Gav2k

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    #7
    Wirelessly posted (Mozilla/5.0 (iPhone; CPU iPhone OS 5_0_1 like Mac OS X) AppleWebKit/534.46 (KHTML, like Gecko) Version/5.1 Mobile/9A405 Safari/7534.48.3)

    Try home plugs
     
  8. HyperX13 thread starter macrumors 6502

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    #8
    Thanks much! I did this and now its really great! I didnt know you could have two APs with same name. I thought there would be some conflict. Thanks for showing me the way!!
     
  9. NogbadTheBad, Jan 9, 2012
    Last edited: Jan 9, 2012

    NogbadTheBad macrumors regular

    NogbadTheBad

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    #9
    Use netspot to do an active survey once you've sorted your wireless out, this will help you pick the correct power levels on the aps and if you need more.

    http://www.netspotapp.com/

    If your going to use homeplugs you can get them with wireless built in.
     
  10. BiggAW macrumors 68020

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    Connecticut
    #10
    How well do they roam to each other? I thought you would need a system like Ubiquiti's Unifi or a corporate level Cisco Aironet system to have seamless roaming from AP to AP. We have that at school, but they have several thousand $700+ Cisco Aironet AP's plus all the licenses and controller that go along with them.
     
  11. Alrescha, Jan 9, 2012
    Last edited: Jan 9, 2012

    Alrescha macrumors 68020

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    #11
    I guess you'd have to define some levels of quality/performance. We use them in our office, people move around from place to place and don't have to think about it. It meets our goal.

    Can you start a streaming movie at one end of the building and have it play perfectly as you roam to the other end? I don't know.

    A.

    From Apple's "Designing Airport Extreme Networks":


    Multiple AirPort Extreme Base Stations can be set up to create a single wireless network. Client computers using AirPort can move from base station to base station with no interruption in service (a process known as roaming).

    To set up roaming:

    Connect all of the AirPort Extreme Base Stations to the same subnet on your Ethernet network.
    Give each base station a unique name.
    Give each base station the same network name and password.
    Set up the base stations as bridges.
     
  12. NogbadTheBad macrumors regular

    NogbadTheBad

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    #12
    Roaming is controlled by the client not the AP, to quote the 802.11 Wireless Networks O'Reilly book :-

    Roaming in 802.11 is entirely driven by client decisions. Where to send the Association Request frames is entirely in the hands of the client system’s driver and firmware and is not constrained by the 802.11 specification in any way. It would be 802.11-compliant, though awful, to connect to the AP with the weakest signal! (An unfortunate corollary is that driver updates to fix bugs may alter the roaming behavior of client systems in undesirable ways.) Access points do not have protocol operations that can influence where clients attach to, and whether they will move or not.
     
  13. BiggAW macrumors 68020

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    #13
    There's definitely some stuff going on at the back-end level, I know the campus systems are specifically set up for roaming to work correctly.
     
  14. belvdr macrumors 603

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    #14
    The setup your school has is for centrally managing all of those APs. The decision to roam to a different AP is up to the client.

    For example, with the Cisco controllers, you can determine what SSIDs go on what AP, what power level they should operate as well as what frequency, and even provide guest wireless access from the same APs on the internal network without granting the guests internal access.

    For using standard home equipment, do what Alrescha says. Just plug them together into a switch and put the same configuration on each AP, with the exception of channel. I believe Apple's gear can auto-select the channel, similar to what Cisco does. I know I have roamed between my APs with some TCP traffic going (mainly VPN to work) and never had an issue.

    Every time you repeat/extend a wireless signal, the bandwidth gets cut in half. So if you repeat/extend using two additional APs, you will now have 1/4 of the bandwidth you started with. Having 7 extenders will cut your bandwidth to 1/128th of the original speed. So, if you have a 100Mb link, you just cut it down to approximately 780Kb.
     
  15. NogbadTheBad macrumors regular

    NogbadTheBad

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    #15
    Intel refer to it as "Roaming Aggressiveness"

    This setting allows you to define how aggressively your Wi-Fi client roams to improve connection to an access point. Click Use default value to balance between not roaming and performance.

    Lowest: Your wireless client will not roam. Only significant link quality degradation causes it to roam to another access point.

    Medium-Low/Medium-High: Allow Roaming.

    Medium: Balanced setting between not roaming and performance.

    Highest: Your Wi-Fi client continuously tracks the link quality. If any degradation occurs, it tries to find and roam to a better access point.
     
  16. BiggAW macrumors 68020

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    #16
    Iiinteresting. So just set a bunch of AP's up to the same SSID and the client should know how to roam between them?
     
  17. belvdr macrumors 603

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    #17
    Correct. I've done this for 12 years or so, with some Linksys WRT54Gs then moved to 802.11n using two AEBS units.

    The client will see one SSID and multiple APs but different MAC addresses. It will choose one and will roam to the other when it feels the need. For the additional AEBS units (i.e. the ones not connected to the Internet), just put them in bridged mode.
     
  18. squeakr macrumors 68000

    squeakr

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    #18
    Yes it is the MAC that really matters, as the SSID can be hidden for broadcast, yet connections still be made. I too used to run the same sort of configuration before changing routers.
     
  19. BiggAW macrumors 68020

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    #19
    And with Airport Express, you can configure multiple units to have identical settings if they are all running off of an Ethernet backbone?
     
  20. belvdr macrumors 603

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    #20
    I would assume so, if it's like a standard AP and it works as Apple advertises. I've never used an Airport Express.
     
  21. rwwest7 macrumors regular

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    #21
    Sounds like a salesman sold you guys something by spitting out b.s. Like someone else already said, roaming decisions are purely client ones. Of course you need your network set up properly for it to seem transparent to the client, but those are decisions/settings that are hardware vendor neutral. Every wireless vendor has claims to fame but at the end of the day they all work pretty much the same.
     
  22. BiggAW macrumors 68020

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    #22
    I got that from the IT guys who actually run it. Based on the comments above, it sounds like the back-end stuff has to do with IP management and AP management, not as to which AP a computer will connect to at any given point on the network. The network consists of something on the order of 3,000 Cisco Aironet AP's stretching well over a mile square in total, and providing IP connectivity to tens of thousands of devices on any given day. They are also ridiculously fast, the new N ones Speedtest in the 70's sometimes, and regularly in the 40-50 range.
     
  23. NogbadTheBad macrumors regular

    NogbadTheBad

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    #23
    They've probably got a bunch of Cisco Wireless Controllers and the Wireless Network Management software, the big advantage of using Wireless Controllers would be a single change would be rolled out with one click of a button.

    I've only used the Motorola/Symbol Wireless controllers but if the Cisco ones work the same way they're they only way to go with a large wireless installation.

    http://www.cisco.com/en/US/products/hw/wireless/products.html
     
  24. belvdr macrumors 603

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    #24
    For one site with a thousand APs, you'll only need 2 or 3 Cisco 5508s to support it. The additional benefit of the controllers is they automatically adjust power to provide proper coverage. Additionally, you can setup guest wireless access through the same APs without providing internal LAN access. One other feature is the ability to upgrade the software on many APs at once.
     
  25. BiggAW macrumors 68020

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    #25
    Yeah, we have two VLANs, one is a web-based login that will support anything with a browser and it's on it's own segregated network, the other is WPA2-RADIUS, that gives full access at full speed to the same network as plugging in.
     

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