How to build a CCIE rack with GNS3 / dynamips — Part 5a, the remote power switch

Ok guys here we are now for the remote power supply. I prioritized this part because a guy from the ieoc forum would like to know more about it.

So whats our goal here:
– remotely switch on/off our equipment
– we want to this quite comfortably from the whole world (I do it with my cell phone 🙂 )
– should be affordable and less than the other remote power supplys you can buy for sometimes a lot more than 100$

So what do we need:
– (0,50$) an opto-coupler (I took a “4N 25”)

– (0,80$) a low current relais for 12V DC with a on/off function

– (1,00$) a mid current relais for 12V DC with a 2-circuit on/off function

– (2,00$) a high current relais for 230V AC (can switch up to 3000Watts), for the people in other countrys who do not have 230V AC power, you should use simliar parts that support 110V AC; the relais needs to be able to switch 2 circuits

– (0,10$) 1x 75Ohm resistor 1/4W (to protect the opto-coupler from getting blasted)

– (5-15$ at ebay) a cisco router with at least two ethernet ports (I used a Cisco 836)

– (take it from garbage or ebay for less than 5$) a (preferably small) network device with a Link-LED that is permanent! The Link-LED must not flash until activity (I used an old SMC Barricade router for this)

– solder

– (few $ on ebay) a small 12V power supply

– (borrow it or maybe you own one) soldering iron/gun

– medium skills in electricity

– (2$) a small sized circuit board

– a cross-over cable

– (2-4$ a little box (made of plastic)

– (4$) a 6x electric socket

– (3$) a 3x electric socket

Overall costs are about 30$ to 40$

When you are working with 110V/230V AC. BE CAREFUL!!! DO IT ON YOUR OWN RISK!!! You should definitely know what you are doing and how AC current works. You should be aware of how to work with voltage and current! I am not responsible for your doing and it is not my intention to let you hurt yourself! Like I said – you do it on you own risk!
I for myself am familiar with electricity and I am allowed to work with voltage

So lets begin. Maybe you wonder, “why is this guy buying all this crap?” but you will see :). By the way it actually does not matter where we begin so dont blame on me with the order of the steps please :).

General Idea of the concept:
The idea is to do the following. I want to logon to the Cisco 836 via telnet/ssh. Then I will go to a fast ethernet port and hit “no shut”. The rack powers up. When I want to power it down, I type “shut” and the rack shuts down.

The concept itself will work this way:
you logon to the router and “no shut” a specific ethernet/fastethernet interface. This interface is cabled with the crossover cable to the noname-router I mentioned and the link comes up. The link LED of the no-name device is lightened up. We remove this LED and put the optocoupler instead. This makes the formerly Link-LED to a small power-switch that can switch up to 150mA. Enough for the 12VDC low-current relais to be switched on. The low-current relais then switches the 230V high-current relais and that relais switches our rack! So link comes up…CLICK – CLICK (the two relais fire up) and the rack is running.

1st step) – Putting the active components together
Here we need the opto coupler which has 2 connectors for the LED inside the optocoupler to lighten up and 2 connectors that will act as the open contact in the circuit that supplys the low-current relais. First we have to open the no-name router and remove the link-led of one of the ports. Remember that you have to measure where the + and where – is as you need to connect the cathode of the opto-coupler to the + and the anode to the +. A good advice is to measure the voltage that the no-name router uses for the link-LED. When that is up to 3V you better use a the resistor we have in our to buy list to one of the contacts, as this protects the LED in the opto-coupler not to get blasted. Here is a picture how I did it. I took two wires, connected them to the mainboard of the SMC and then attached them to the circuit board and then to the opto-coupler.

Here is the soldering plan how you have to cable the parts together.

2nd step:
We need to connect the low-current relais now. First put it onto the circuit board, then connect the reel with the 12V DC power supply via the opto-coupler in circuit.

3rd step:
We need to connect the high-current relais now. Put it onto the circuit board and connect the reel of it also to the 12V DC (or 230V depends on the operating voltage of the reel) power supply with the low-current relais in circuit.

4th step:
Cut off the cable (in the middle) of the 6-port electrical socket (you can also use an other socket with more ports if you like to) and wire the 230AC source (where the plug is) to the input contacts of the high-current relais and the outport contacts of the relais to the socket. Be careful that you have a good and solid connection because here about up to 1000W can flow depending on how many devices you want to power.

5th step:
Power up the DC power supply and put the 230V source for the high-current relais under voltage. Be sure that all contacs are well done and that your safety is the most important thing you should look after.

6th step:
Connect the port from the no-name router where you removed the led and connected the opto-coupler with the crossover cable to one of the free ethernet/fastethernet ports of your cisco router.

7th step:
Connect the devices you want to power up to the sockets that are connected to your high-current led.

8th step:
Telnet/SSH into the cisco and “no shut” the port. You should heat two silent CLICKs and the devices should power up!

9th step:
Put everything into a box of plastic and fix it with hot-glue for example.

Here is a picture of my complete switch. Does not look like candy, but I am sure that I will build another one that looks quite professional.

If you have a server connected to the remote power switch, make sure that in BIOS you set the ACPI settings the way that the server will power up as soon as power is connected. If you do not, the server will stay offline when the 230V AC comes back. You then could fire it up using Wake On LAN if you have the possibility to.

So thats roughly all I guess. If you are missing something. Just write a comment and I will try to answer your questions.
Here is a video where you can see that it actually works.

Regards and have fun with this affordable self-made solution!


About markus.wirth

Living near Limburg in Germany, working as a Network Engineer around Frankfurt am Main.
This entry was posted in Part 5a and tagged , , , , , , , , , , , , , . Bookmark the permalink.

17 Responses to How to build a CCIE rack with GNS3 / dynamips — Part 5a, the remote power switch

  1. D says:

    Very nice DIY remote power solution. Your youtube video shows lab power consumption adding up to 400W during start-up. Do you happen to know how much power the lab consumes in ready state (idle with initial configs) or when dealing with a completed mock lab?


  2. zool85 says:

    Thanks for the comment!
    Under full load, the rack consumes about 450-470Watts. Within all routers running and idling just about 350-370Watts.

  3. Jobin says:

    Do u have a noob inscrutable 🙂

  4. Addy says:

    I am looking for a solution like this – to turn devices on/off remotely – but I am not -at all- familiar with voltage. Could you give an alternate solution I could buy, that would have similar effect? Maybe one I can find on eBay? BTW: your site is AWESOME!! Thanks very much for the detailed explanations, very, very clear and easy to understand! Greetings!

  5. markus.wirth says:

    Thanks for your nice post! Ahm…yeah sure there is something you can buy. Do you need US plugs or different ones?

    • Addy says:

      Sorry for the late reply…. I would need US plugs, yes.. and I saw your comment below, I am taking a look at these right now. Thanks!

  6. markus.wirth says:

    In Germany there you can buy those ones here:
    Are a good equal of price and value. You have a WEB GUI and you can turn on and off each single socket.


    • Addy says:

      I was looking at the website, thanks, it is awesome! but on the pictures it seem that the plugs are not the same as the US ones =(

      • markus.wirth says:

        Check out this user at ebay US -> “weesolutions” or search for this term “Smart IP-based PDU Power Reboot Switch” or you can enter this number in the search field of ebay “120864414829″. Is that more like you are searching for?
        Let me know!

  7. markus.wirth says:

    Okay so you are looking for US plugs…well I will dig into it tomorrow. I am on train right now. UMTS connection is quite creepy. I keep your comment in my email folder and will mail you. If I dont find it by myself, I know a guy who definitely knows!

  8. markus.wirth says:

    Check out this user at ebay US -> “weesolutions” or search for this term “Smart IP-based PDU Power Reboot Switch” or you can enter this number in the search field of ebay “120864414829”. Is that more like you are searching for?
    Let me know!

    • Addy says:

      Hi Markus! For some unknown reason, until now I am back to your post. I am so so so sorry for late reply. I greatly appreciate your help, and I am taking a look at your suggestions right now. I will let you know how it goes once I find what I am looking for (if its ok). Thanks again for your awesome website 🙂

  9. This valuable blog post, “How to build a CCIE rack with GNS3 / dynamips
    — Part 5a, the remote power switch | ::
    Markus´ journey to the CCIE R&S ::” displays the fact that
    u really understand just what you’re talking about! I really thoroughly agree. Thank you -Valentina

  10. What’s up to every one, the contents present at this website are truly remarkable for people experience, well, keep up the good work fellows.

  11. fnb says:

    I read this post completely regarding the comparison of most recent and preceding technologies,
    it’s awesome article.

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