Author Topic: WLIP config via single port router?  (Read 4175 times)

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Offline Flag

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WLIP config via single port router?
« on: March 12, 2011, 02:19:36 AM »
Running a single port wireless router and without introducing a third party hub/switch what "simple" options are there for configuring an Envoy?

Via remote IP is not really a viable option in this case.   

Offline johnd

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Re: WLIP config via single port router?
« Reply #1 on: March 12, 2011, 03:11:15 AM »
I think that you've effectively answered your own question.

If there's only one port on the router and no remote access possible then how can any other device gain access to the Envoy/logger while the installation is in this configuration?

The only option is to disconnect the logger from the one-port router and connect it temporarily into some other LAN while you effect the reconfiguration. You obviously need to be using a compatible static IP address for the logger or DHCP but this detail aside there should be no problem.
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Offline Flag

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Re: WLIP config via single port router?
« Reply #2 on: March 12, 2011, 04:17:06 AM »
I haven't come up with any other solution either but was just checking.

Typically the router handles a direct static connection between WLIP and uses DHCP for an introduced laptop etc but requires the addition of a hub etc which of course then also requires temp power.

Offline johnd

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Re: WLIP config via single port router?
« Reply #3 on: March 12, 2011, 04:41:18 AM »
Typically the router handles a direct static connection between WLIP and uses DHCP for an introduced laptop etc but requires the addition of a hub etc which of course then also requires temp power.

Yes I understand the problem - by coincidence I run a WLIP in a similar configuration at a remote site with solar power only. It is a definite nuisance to power up a hub/switch, which needs to be powered by its own mains adapter hence needing an inverter also to be fired up.

I keep thinking that there must be eg a specialist 2-port hub/switch that I could buy which ideally would be:

1. Powered by 5v or 12v DC (the two voltages that I have readily available from the solar PSU);

2. Very low power consumption so that I could it powered up during periods when I'm running reconfiguration tests or checks on the system, eg for maybe a day or two at a time;

3. With a pass-through switch so that you could power down the hub completely and just allow the WLIP to be connected through to the router without haviung to unplug/replug things all the while.
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Offline Flag

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Re: WLIP config via single port router?
« Reply #4 on: March 12, 2011, 07:44:11 AM »
I was hoping somebody might have made a USB powered mini hub? Then again I doubt it would increase a single port router all that much if they simply added a second port? Surely there are similar setups requiring a second configuration type port?

Offline johnd

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Re: WLIP config via single port router?
« Reply #5 on: March 12, 2011, 08:22:32 AM »
Hmm, made the same mistake yet again! It does of course have to be a 3-port hub/switch - there's really no such thing as a 2-port one - because you always have to have a port for the onward connection.

One that I have found is this one:

http://www.voipon.co.uk/cyberdata-010988-p-2535.html

(UK link but I'm sure that the same partis available elsewhere). 3 ports, low(ish) power, powerable from USB. Expensive but I guess it's not a commonly requested part.
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Offline dalecoy

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Re: WLIP config via single port router?
« Reply #6 on: March 12, 2011, 10:29:02 AM »
Thanks for mentioning that device.  Of course, as usual, there are tradeoffs.

In the US, that switch retails for around $55.  A 5-port AC (mains) powered switch retails for around $15.

Offline xykotik

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Re: WLIP config via single port router?
« Reply #7 on: March 12, 2011, 11:01:02 AM »
Does that router have only one LAN port because it is primarily a WLAN (Wifi) router?  My immediate thought was to use a wireless connection to your network/router for your PC/laptop and reserve the wired port for your WLIP. (I just saw a USB-802.11n yesterday on the clearance shelf for about $25). 

Or, is the reason for a single port that it is the network jack coming directly out of your modem?  In that case, the DHCP server may be upstream, and you would need a local DHCP-server router to assign seperate IPs to the devices and NAT (network addres translation) to the IP assigned by the modem/isp.  This is pretty much PnP, but it still requires hardware that must be powered somehow.  And then it would not "pass-through" to the original IP, because of the NAT.  The intermediary router (with DHCP server) would have to remain in place.

Of course, it could be that neither of these is your setup.
« Last Edit: March 12, 2011, 11:05:55 AM by xykotik »


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Offline SLOweather

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Re: WLIP config via single port router?
« Reply #8 on: March 12, 2011, 11:04:20 AM »

In the US, that switch retails for around $55.  A 5-port AC (mains) powered switch retails for around $15.


Almost certainly, the $15 switch is powered by a wall-wart. What voltage does the switch itself take? a quick survey of small switches I have here shows power supply voltages of 3.3, 5, 9 and 12 VDC.

Offline dalecoy

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Re: WLIP config via single port router?
« Reply #9 on: March 12, 2011, 12:21:55 PM »

In the US, that switch retails for around $55.  A 5-port AC (mains) powered switch retails for around $15.


Almost certainly, the $15 switch is powered by a wall-wart. What voltage does the switch itself take? a quick survey of small switches I have here shows power supply voltages of 3.3, 5, 9 and 12 VDC.

There are several common brands (Linksys/Cisco, Netgear, Trendnet, D-Link, Medialink, etc.) - so there's no general answer.  But yes, all are powered by a wall-wart.  The output of the wall-wart will be low voltage, but may in some cases be AC rather than DC. 


Offline johnd

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Re: WLIP config via single port router?
« Reply #10 on: March 12, 2011, 01:27:34 PM »
Does that router have only one LAN port because it is primarily a WLAN (Wifi) router?...
Flag will need to answer that question because he/she is obviously the OP for this thread.

But the installation that I'm chiming in about is a 3G router with only a single Ethernet port that's at a remote site that operates only with solar power. So from my perspective (which may well be different from Flag) it's vital that any additional network component installed at that site uses a minimal amount of power. A 5-port switch might be OK, especially if it's one of the models that powers down ports that are not actively in use, but it does need to use as little power as possible and - for my particular installation - to run off either 5v or 12v because these are the only two voltages I have readily available. Using a mains adapter, while feasible via an inverter, is not good news because of all the power inefficiencies involved.

The 3-port switch I linked to seems just to require 350mA @ 5v , ie 1.75W, which would equate to a power draw of around 200mA from the 12v solar battery (with a decent DC/DC converter operating at 70%). So any other hub/switch, whether 3- or 5-port, would need to match that and I haven't found another that uses no more than 0.2A from a 12v source. Maybe they do exist - it's just not easy to find one.

Incidentally, this just highlights the problems you face when looking for parts for a non-standard application. So many network devices just seem to assume that you're going to have AC mains available. But there's a whole market sector out there to power instrumentation and data links at remote sites, where only solar/wind power at eg 12v is available and power efficiency is vital. This sector is quite poorly served at present.
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Offline SLOweather

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Re: WLIP config via single port router?
« Reply #11 on: March 12, 2011, 02:05:27 PM »
Incidentally, this just highlights the problems you face when looking for parts for a non-standard application. So many network devices just seem to assume that you're going to have AC mains available. But there's a whole market sector out there to power instrumentation and data links at remote sites, where only solar/wind power at eg 12v is available and power efficiency is vital. This sector is quite poorly served at present.

I know what you mean. I have a WeatherElement site on solar. Including the EVDO router, the WeatherElement hub, and a linear 5V supply I made to run the Davis console, the whole thing draws about 7 AH per day from the site's 400 AH 12 VDC solar system, updating 1x minute to the server.

It worked great for a while and then Verizon coverage on the mountain top got spotty due to illegal cellular repeaters in the valley. Last month I had to change from the hockey puck antenna to a small Yagi. Since then it's worked great.

Who's 3G router are you using?

Offline dalecoy

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Re: WLIP config via single port router?
« Reply #12 on: March 12, 2011, 05:48:57 PM »
The 3-port switch I linked to seems just to require 350mA @ 5v , ie 1.75W, which would equate to a power draw of around 200mA from the 12v solar battery (with a decent DC/DC converter operating at 70%). So any other hub/switch, whether 3- or 5-port, would need to match that and I haven't found another that uses no more than 0.2A from a 12v source. Maybe they do exist - it's just not easy to find one.

I looked at the wall-warts for 3 different switches (two 5-port and one 8-port), and each of them has a rated maximum output of approximately 5 watts.  I really don't want to take things apart to see what the actual draw of the switch is, but I would expect it to be considerably less than that 5 watt rating.  You might consider investing in one, just to find out what it really is, before buying the expensive alternative. 

Offline dalecoy

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Re: WLIP config via single port router?
« Reply #13 on: March 12, 2011, 06:01:42 PM »
A very quick search turned up the TrendNet TE100-S5 that says:
Power Consumption 2.8 watts (max)
5 VDC.

Offline Flag

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Re: WLIP config via single port router?
« Reply #14 on: March 12, 2011, 06:05:14 PM »
Quote
Hmm, made the same mistake yet again! It does of course have to be a 3-port hub/switch - there's really no such thing as a 2-port one - because you always have to have a port for the onward connection.

Was referring to a simple 2-port router, no reason why a router couldn't have just 2 ports which some do but they are no where near as common as the 1-port models.

Quote
Does that router have only one LAN port because it is primarily a WLAN (Wifi) router?  My immediate thought was to use a wireless connection to your network/router for your PC/laptop and reserve the wired port for your WLIP.

Yes most have only one LAN port and no WLAN. Yes I suppose WiFi could be used to configure but the rest of the time it is a power overhead that is not required and having only one LAN port then there is no way to disable/enable the WiFi on demand.  

Quote
But the installation that I'm chiming in about is a 3G router with only a single Ethernet port that's at a remote site that operates only with solar power. So from my perspective (which may well be different from Flag) it's vital that any additional network component installed at that site uses a minimal amount of power

Yes that's the typical remote setup scenario.

Quote
Who's 3G router are you using?

There's a heap of these small industrial routers around such as Sierra
http://www.sierrawireless.com/en/productsandservices/AirLink/Intelligent_M2M_Gateways.aspx

The typical 3G 4+1 LAN port with WiFi gateway & 12VDC power does the job but it comes in a box 10 times larger with equiv higher power requirements such as something like a Netcomm3G9W  


Offline xykotik

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Re: WLIP config via single port router?
« Reply #15 on: March 12, 2011, 06:44:37 PM »
OK, here's my last thought, then I am out of ideas or don't understand the sitch enough to offer another idea...

Does this one-port router offer configurable DHCP?  Can you set a static IP for the WLIP's MAC?  If so, how about using any ol' switch/hub ONLY while you are configuring it, then remove the switch/hub and plug the WLIP back into the router directly?  Would it then assign that IP back to the WLIP and play nice?

I don't have a WLIP, so I don't know if it is a problem to interrupt the LAN connection like that.  I have an IP camera for which I reserved an IP (left it "DHCP" in camera, "RESERVED" in router for the camera's MAC), and I unplug/unpower it all the time to relocate and it always finds its way home.  Not knowing any more about it, that's what I would try.


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Offline Flag

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Re: WLIP config via single port router?
« Reply #16 on: March 12, 2011, 07:02:29 PM »
Does this one-port router offer configurable DHCP?  Can you set a static IP for the WLIP's MAC?  If so, how about using any ol' switch/hub ONLY while you are configuring it, then remove the switch/hub and plug the WLIP back into the router directly?  Would it then assign that IP back to the WLIP and play nice?

Yes one-port router/gateways generally have DHCP and Static and yes a hub/switch will work but then you have to provide external power to the hub plus another 2 LAN cables etc. Configuring the WLIP with a static IP has no problems when re-connecting.

Another thing that works instead of the hub is a multi-port router/gateway(WiFi) as long as the gateway address and DHCP/fix IP is configured the same. Much more expensive option and could be used directly inplace of a single port router apart from the high over head power requirements and physical size.

Oh how a 2-port router would make things that much easier.   

Offline dalecoy

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Re: WLIP config via single port router?
« Reply #17 on: March 12, 2011, 11:42:57 PM »
Oh how a 2-port router would make things that much easier.   

Are you required by your service provider to use this particular router?  If not, why not just replace it with one that has more ports?

Offline Flag

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Re: WLIP config via single port router?
« Reply #18 on: March 13, 2011, 03:36:33 AM »
Oh how a 2-port router would make things that much easier.    

Are you required by your service provider to use this particular router?  If not, why not just replace it with one that has more ports?

No nothing to do with a service providor it's all to do with power, the typical 4+1 port router LAN/WLAN requires more power than the 1-port LAN (NO WiFi which you don't want anyway). It's also about size and footprint when trying to fit all this stuff into an enclosure.

Also Davis's 5 volt systems might appear logical (to some) but all the other gear that generally runs with this weather stuff is 12 volt or at best 9-30 volt and when running on solar power tends to become a two power source system.    

Offline johnd

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Re: WLIP config via single port router?
« Reply #19 on: March 13, 2011, 04:26:37 AM »
Was referring to a simple 2-port router, no reason why a router couldn't have just 2 ports which some do but they are no where near as common as the 1-port models.

Absolutely right - no reason at all AFAIK, provided the two ports are built into the router. I was thinking about an add-in hub/switch, which is - only in part I know and as a non-preferred solution, albeit the only available one AFAIK - what you mentioned. In this context a 2-port hub (ie one port in and one port out) wouldn't add much, aside perhaps/possibly for some extra packet processing.

Quote
Who's 3G router are you using?

The one I'm using is a MultiTech Multimodem GPRS (not sure if this is a current model any longer with an Ethernet interface - it is 3-4 years old now.) And yes I know plain GPRS isn't very fast, but it's fine just for passing the small per-minute amount of WLIP data.

Actually, for all the talk about minimising power drain from an additional hub/switch, it is the GPRS/3G router that is the real power hog. But I guess if it's going to be radiating up to 2W of RF power then several different makes/models of router are going to be wanting much the same power overall of 3-5W depending on frequency band, because it's the RF transmission requirement that dominates the power consumption and not the rest of the circuitry. Two things I wonder about:

1. How much it might be possible to reduce average router power draw by using a high-gain yagi antenna for the cellular signal. Aren't 3G routers supposed to be clever enough to limit Tx power according to the strength of the signal from the cellular base station?

2. In the context of eg the WLIP, which only needs to transmit data every minute, is this long enough for the router to send its cellular Tx circuitry to sleep and then to set up the connection again when data needs to be passed. So is it worth looking for a router with an auto-sleep function (assuming that they do exist) and would this work OK with a WLIP logger?

BTW I don't know whether Admin is likely to read this post, but I'd be really pleased to see a forum/subforum set up dealing specifically with remote wx sensing - ie just the sort of topic we're dealing with here - it's a topic that's not really covered much elsewhere and can be tricky territory for anyone interested in setting up such an installation who is not already an M2M professional.
« Last Edit: March 13, 2011, 06:27:48 AM by johnd »
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Offline SLOweather

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Re: WLIP config via single port router?
« Reply #20 on: March 13, 2011, 10:20:18 AM »

BTW I don't know whether Admin is likely to read this post, but I'd be really pleased to see a forum/subforum set up dealing specifically with remote wx sensing - ie just the sort of topic we're dealing with here - it's a topic that's not really covered much elsewhere and can be tricky territory for anyone interested in setting up such an installation who is not already an M2M professional.

I just created one. Thanks for the suggestion.

Remote Weather Monitoring

Let me know if you have a better name.