+ Post New Thread
Results 1 to 4 of 4
Wireless Networks Thread, AP energy efficiency - PoE scheduling: Experiences or recommendations? in Technical; G'day We're yet going live with our first wireless network on parts of our campus. At the moment we plan ...
  1. #1

    Join Date
    Apr 2012
    Posts
    22
    Thank Post
    0
    Thanked 0 Times in 0 Posts
    Rep Power
    0

    AP energy efficiency - PoE scheduling: Experiences or recommendations?

    G'day

    We're yet going live with our first wireless network on parts of our campus. At the moment we plan to go with a set of UniFi UAPs and hope to focus then on the UAP-Pro. One thing that I feel is seldom considered and I haven't found experiences on the internet is is the power draw of access points and overal energy efficiency of a wireless campus network. Maximum power draw in the specs. of UAP (4W) and UAP-Pro (12W) may not be that high, but if we expect like 100 APs spread over the campus, this could go up to (ok, theoretical) 10'000 kWh per year added to our power usage just for wireless networking.

    Our Switches seems to be able to schedule PoE ports so this would allow to power down most of the APs outside of school hours (like 8 PM - 6 AM) plus weekends (even holidays!) where nobody will be on place using the network.
    I have done some calculations and think that we could engage some considerable energy efficiency improvements (up to 50% compared to 24h uptime) if we do scheduled shut down of APs during times there is nobody on place.

    - I'll do some testing on my own - but what are users here thinking about powering off APs on daily base?
    - Will it bring more headaches compared to 24h x 365days uptime - aka: is it even worth the additionaly work?

    Currently paying the power bill is not the issue of the IT services... but still I feel considering energy efficiency in current times should be part of such projects - not?
    Last edited by koffi2k; 27th July 2012 at 08:13 AM.

  2. #2

    SYNACK's Avatar
    Join Date
    Oct 2007
    Posts
    10,991
    Thank Post
    851
    Thanked 2,653 Times in 2,253 Posts
    Blog Entries
    9
    Rep Power
    764
    Maunal switch off of 100 APs is going to be so much of a troule causing mess that you'd be forever chasing them. Your users may be reliable but if they are anything like the species here I'd automate or just leave them on.

  3. #3

    Join Date
    Jul 2006
    Location
    London
    Posts
    1,241
    Thank Post
    110
    Thanked 242 Times in 193 Posts
    Blog Entries
    1
    Rep Power
    74
    One approach would be to choose your POE switches/injectors carefully. I understand that a lot of them can't completely shut down their consumption of power even when a non POE device is connected. <-I have not verified this, nor can I recal where I read it.

    Ultimately though, doing more takes more energy. Probably easier to offset the AP's footprint.

    Think about your desktop PC purchases, you can save 100W's per device in some cases. That dramatically reduces the cooling requirements too.

    Then you can look at turning off a couple of air con units. Energy saved.

  4. #4

    Join Date
    Apr 2012
    Posts
    22
    Thank Post
    0
    Thanked 0 Times in 0 Posts
    Rep Power
    0
    Quote Originally Posted by SYNACK View Post
    Maunal switch off of 100 APs is going to be so much of a trouble causing mess that you'd be forever chasing them. [...]
    The switches feature a scheduling functionality for specified ports - if things work well, it means that we'd not have to touch that configuration manually afterwards.
    I wouldn't even be considering this if there was no option to do that on automated basis (even scripted) - I definitely don't want to chase after 100's of ports.
    I'll have to figure out if rebooting the APs doesn't mess up the wireless network.

    Quote Originally Posted by psydii View Post
    One approach would be to choose your POE switches/injectors carefully.
    I understand that a lot of them can't completely shut down their consumption of power even when a non POE device is connected. <-I have not verified this, nor can I recal where I read it.
    Definitely something to check out with our switches. AFAIK it should cut the power so that the AP will be powered off and re-powered when the port is scheduled to come back online.

    Quote Originally Posted by psydii View Post
    Ultimately though, doing more takes more energy. Probably easier to offset the AP's footprint.
    Ubiquiti's dual radios and Gbit-uplink AP seems to be drawing compareable power when, I gave a look at the Cisco 1142N (13W).
    Yup, we absolutely want UAP-Pro (UAP 4W is 2.4GHz only) and real PoE without adapters if we can (48V to their 24V is also adding losses). In general I don't expect the power draw of APs to go down with future wireless standards if I'm not too pessimistic.

    Quote Originally Posted by psydii View Post
    Think about your desktop PC purchases, you can save 100W's per device in some cases. That dramatically reduces the cooling requirements too.
    Then you can look at turning off a couple of air con units. Energy saved.
    Allas, the only air con is in the server room and "quite required", we've already taken measures where we could (or could afford with meanigful ivestments/replacements). ATM it's about measuring the expected grow in the required power budget simply because of this new network.

SHARE:
+ Post New Thread

Similar Threads

  1. Replies: 0
    Last Post: 23rd March 2011, 07:45 PM
  2. Help or Recommendations for Network Infrastructure
    By gmiller in forum Wireless Networks
    Replies: 1
    Last Post: 10th February 2011, 05:12 PM
  3. Becta - Requirements or recommendations
    By Craggus2000 in forum General Chat
    Replies: 1
    Last Post: 22nd March 2010, 08:33 PM
  4. Replies: 6
    Last Post: 16th May 2009, 07:38 PM
  5. Replies: 7
    Last Post: 22nd October 2007, 10:05 PM

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •