FabFi 2.0 QA

From Fab Lab wiki

Jump to: navigation, search

Contents

FabFi 2.0 Q&A

There are lots of FabFi users. They have lots of questions. For every question there is an answer. Those answers are posted here.


Linking between two reflectors that do not point at each other

Q: Hello Kieth This is good news that we can share the reflectors but, if the second wrt is not in straight position and will be bending in almost 50 or 90 degree angle from the reflectors is it talk to each other if we point it ?

regards


A: [FFUser,]

This is a very good question:

The strongest signal is straight out of the center of the reflector, but some signal will go off slightly to the side. The farther from the center line you are, the weaker the signal will be, but at the center line we know we can send signals many miles!

A link very off to the side will not go nearly as far, but it may still connect at hundreds of meters even though the signal is much weaker. A good example of this is the hospital uplink, ff5. This link serves as an uplink for both ff6 and ff14, which are at least 30degrees apart. It can also see ff28, which is very far away and off-center. (if you are on the network, you can log onto any device and see the LQ numbers for the existing reflectors as explained in the wiki page below)

For any link that is off-center you will have to test the link quality, of course. The "sharing reflectors" section on the wiki explains how to test: http://wiki.fablab.af/index.php/FabFi_Deployment_Guide#Sharing_Reflectors

Also note: It is possible to build reflectors in many shapes. The shape we have designed is supposed to send a signal very far in a narrow line, but another shape could be used to provide even coverage over a wide area at a shorter distance.

~Keith


Is my Router Supported?

Q: Hi Keith and Amy,

We are about to start working on a new connection in the network. The person who wants the connection just brought us two routers that are not exactly the same as the ones we have been using.

Below is the model no. and some more about the routers. Please tell me if we can install the new software in them. (We want to know if these routers will work in our Fablab network).??

- wireless-G Broadband Router

- Model No. WRT54G2

- Certified Refurbished Product

Looking for and forward to hearing back from you!


A: For future reference, you can determine if a router is supported by following this link: http://wiki.fablab.af/index.php/Router_Tech#Determining_if_Your_Router_is_Supported (ignore any certificate errors that pop up).

when you click through all the links you should get to the linksys page here: https://wiki.openwrt.org/oldwiki/openwrtdocs/hardware/linksys/wrt54g

The table on the above page will help you determine if it is good. If it is truly a v2, it should be fine, but check the table in the link above.

~Keith


Channels, IPs and Passwords

Q: Keith,

With my existing channel being 1 (and we need to change to 11), do we still use http"//10... or //1...? Might you be able to remind me what the SSH username and pw are? I guess the bug idea below isn't that relevant? I have slow internet at home. I assume I can do it from my place on Firefox...

Thanks.


A: For Clarification: GUI = Graphical User Interface. A GUI, in this case is the web form you see in your browser that lets you change stuff.

Re: procedures on the wiki and Bugs in the GUI. Any procedure that is posted on the wiki works around all the bugs I know of and should work fine.

Re: passwords. The user is always 

root

The password is whatever you selected when you ran the setup script. If you forget the password, you must follow this procedure up to but NOT including the TFTP Step, then download and run the configuration script again using the procedure that begins here.

Re IP: Finally, the IP address is permanent, unique to a particular fabfi# and independent of wireless channel.


At the risk of providing too much information, this is how fabfi nodes are addressed:

  • Every Fabfi has four different networks, called WAN, LAN, MESH, and WIFIMESH. Each network has a specific purpose, and every fabfi has a unique address on every network (this means that it has four IP addresses).
    • MESH and WIFIMESH are used to connect Fabfis together
      • The MESH IP is always 10.101.0.FF#
      • the WIFIMESH IP is always 10.102.0.FF#
    • LAN is for connecting individual computers or home networks.
      • The LAN IP is always 10.103.FF#.1
    • WAN is used to connect directly to an internet uplink, if you happen to have it...
      • the WAN IP depends on what your ISP provides you (if you have one)
  • When you connect your computer to a fabfi, you connect to the LAN. This means the best IP to use for talking to that fabfi is 10.103.FF#.1.
  • It is possible to see any of the IPs listed, however, from the LAN. By extension, this means you can directly talk to any other fabfi in the network by using any one of its IP addresses.
  • Example:
    • I am connected to FabFi24. This means the IP of my computer will start with. 10.103.24. The last number will probably be something in the 100s. examlple: 10.103.24.118
    • I can talk to my FabFi using the address 10.103.24.1
    • If I want to talk to Fabfi33, i can use the address 10.101.0.33 or 10.102.0.33
      • I can also use 10.103.33.1, but for a number of reasons it is best to avoid using the 10.103 address for nodes you are not directly connected to.

REMEMBER: The web GUI listens on port 8080. so you need to add :8080 after the IP address in the URL, like this: 

http://10.103.24.1:8080

hope this helps.

~Keith


My fabfis won't connect to each other!

Q: Keith,

Here is the problem:

* There is two routers. They don't send signals. The one at the water tank is connected to another [existing] router to make mesh. If you plug your computer to the [new] one at it (water tank one) it works. If you replace the [new] water tank router with the one that goes at home and then plug it into your computer, internet still works. But when you set one at the house and the other at the water tank, there is no connection between them. Internet doesn't work at home. So I think the two router are not talking to each other- they don't send signals. I placed them both next to each other, pointing to each other at the water tank but they did not work.

I am looking forward to hearing back from you.


A: [FFUser],

Thanks for the additional info. I am glad that you tested both connected to the internet to make sure they work. This is a good test to show the internet is working on both before you try finding the net through the link.

the testing of the internet, however, is not perfect for figuring out if the routers are connected. It is possible for the routers to talk to each other, but for the internet to be broken.

When you have trouble getting two routers to connect, you can always try to fix them by running the config script again on both routers as explained here.

when running the script, place both routers on the same channel with the same distance setting. Remember to type d when asked if you want to use the default WEP key.


If you would like to try to fix the problem without running the script you may follow these instructions:

The simplest test of the link between the two routers is as follows:

  • Turn them both on and let them boot up all the way (at least 2min)
  • Plug into the LAN port of one with your laptop
  • Make sure you get a correct IP address on your laptop. It should be 10.103.FF#.x where "FF#" is the Fabfi# and "x" is any number other than 0, 1, 255 or 254.
  • Open a command prompt or terminal
  • Type ping 10.103.FF#.1 with your router's FabFi#. If this works you're connected to the local router correctly. (for linux use ctrl^c to stop pinging)
  • Type ping 10.102.0.FF#. where FF# is the fabfi number of the REMOTE (wirelessly connected) router. If this works, your routers are linked and your problem is with connection to the internet.

If you cannot ping, the channel or bssid of the wireless is likely to be wrong on one of the routers. You can check this on each router by: 

wl channel

you should get two numbers back, they should both be the same (if they are not you have the problem explained here). The number you get is the channel.

  • Run the command 
wl bssid

you will get a string of numbers and letters back. like this: 

##:fa:bf:f1:fa:bf:f1

where ## is the wireless channel. Example, if the number you got back from "wl channel" was 1, your bssid should be 

01:fa:bf:1f:ab:f1

if this is not the case you will have to change the BSSID as explained here

repeat the process above for the second router. All of the settings must be the same on both routers. If they are not, you must correct it by following the channel change steps here.



Reconfiguration of FF2.0 Routers

Q: accept my worm and hope you had a safty trip to USA and have a happy life with your family my dear to day i traied to ping antinnas for [name] house i change the place for antinna in [name] house now it seems very clear no trees no other things between each of them but the internet does not work in [name] house i dont know is the problem is in router configration or other thing please give me direction what should i do. and also please send me complet note for the configration of routers such you made before for the router configration. thanks, [FFUser]

A: Hello [FFUser],

I am glad to hear from you. All is well with me and my trip was very easy. I hope all is well with you and your family too.

If you cannot connect from far away, bring the two FabFis close together and see if they can connect to each other. When the devices are close together, you should be able plug your computer into one FabFi (use port 4 for LAN) and ping the other FabFi (NOTE: When you plug into a fabfi, you should get and IP address that starts with 10.103.FF#). To do this, you open a command prompt (windows) or a terminal window (linux) and type:

ping 10.103.FF#.1

Where FF# is the number of the Fabfi you want to talk to. If you can ping, you know they are connected. If you cannot ping, the easiest thing to do is to reconfigure the routers using the script. This will ensure that all the settings are what you expect.

Remember: Every node must be on the same wireless channel and have the same WEP key. Every node must have a unique FabFi #.

Please let me know what you learn.

Best, Keith

Retrieved from "http://wiki.fablab.af/index.php/FabFi_2.0_QA"
Personal tools
Donate
Ads