802.11n greenfield mode?

Discussion in 'Networking and Wireless' started by Peon, Sep 12, 2018 at 10:07 PM.

  1. Peon

    Peon Notebook Deity

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    I'm in the process of setting up a new router, and it struck me that 802.11n has been out for almost 10 years now, and I don't have any b/g devices anymore.

    That said, I've heard that all greenfield mode does is prevent b/g devices from connecting and slowing everyone else down, and that performance is the same as compatibility mode when only n/ac devices are connected. Is that true, or are there actual benefits to using it?
     
  2. downloads

    downloads Super Moderator Super Moderator

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    Performance of greenfield mode will be slightly better because certain things won't be transmitted twice (like legacy preamble and HT preamble) but that does not have a significant negative effect on throughput.

    There is another thing worth mentioning here - it's not about you not having b/g devices anymore - it's about any of the neighbors that have Wi-Fi networks overlapping with yours having b/d devices or not having them - their devices also "understand" RTS/CTS frames that are sent in mixed mode.

    All in all - greenfield mode does not offer much in terms of performance gains but enabling it might cause issues even if legacy devices are being used on a different network (not yours but with overlapping or the same channel)
     
  3. Peon

    Peon Notebook Deity

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    I'm glad I asked - given the coverage about greenfield mode from way back when 802.11n was new never mentioned anything about neighboring networks potentially interfering with it, the thought hadn't even crossed my mind. I'll be keeping the new router in compatibility mode :)
     
    Charles P. Jefferies likes this.
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