Question on wireless topology? (Help) WGB Noob.

[jtadamofod81]

Hello,

We have 3 buildings  all about 300 yards apart and we are trying to create 2 wireless point-to-point connections to the middle building.   I have 4 Cisco 1242 APs with 4 yagi antennaes to be mounted on the roof.  So 2 APs would be placed on the middle building and then an AP would be placed on each other building.  Because the buildings are in opposite directions, we opted for directional antennaes rather than omni.  Essentially I want all three buildings on the same network.  So my question is how would I configure these?  Would I create 2 workgroup bridges on the middle building?  Then would the two other buildings be set up as non-root bridges?  I'm assuming I would set up the non-root bridge APs with a static IP within the same network or would they DHCP wirelessly?  Any guidance or direction would be extremely helpful.  Thanks folks!

Jeremy

[George Stefanick · Accepted solution]

Hi Jeremy,

Welcome to CSC. I see its your first post on the forum. Its not hard to do a PtP (Point to Point). I will share with you a link to get you started.

But a few things to clarify. You dont want to do a WGB,rather you want to do a BRIDGE. A WGB bridge is used to connect say a handful of wired devices to an access points and THAT access points connects to the wireless network. Thats a work group bridge.

Also you might consider a PtMP. This is a point to multi point. Whereby the building in the middle is the ROOT and the other 2 buildings are slaves. Cuts down on a 4 ap.

A few basics to cover quickly.

Your bridge (pairs) will all have to be on the same channel. So if you use the 4 bridges in your exmaple you should have 1 set on 1 channel and the other set on a different channel

Prior to installing your bridges make sure everything is working on the ground first

When you do bridging, 1 bridge out of the set will be root and all other bridges connected to that root are slave. In your design you will have 1) root-slave and 1) root-slave. If you go a PtMP you will have 1 root and 2 slaves

Here is the link. Its for a 1300 but the concept is the same.

http://www.cisco.com/en/US/tech/tk722/tk809/technologies_configuration_example09186a008058f53e.shtml

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Thanks!

[Leo Laohoo]

George has good points (+5).

1.  What kind of yagi antennas?

2.  Clear line of sight or not?

[George Stefanick]

Its always nice to get points from a ViP!

[jtadamofod81]

First and foremost, I'd just like to extend my gratitude for the prompt response.  It's nice to not be condescended due to ignorance, which is quite common in this field.  George, your input was extremely insightful and will no doubt be implemented and rated.  Leo, the physical layer isn't a concern as I have already been assured that LOS and the antennas will be more than enough for what I'm trying to accomplish. 

The ambiguity lies in the configuration.  The gear has already been purchased, so I was told to use all of it.  4 1242 ag and 4 yagi antennas.  So if I grasp this correctly, using them all, the middle building will have 2 root bridges and the 2 other buildings on opposite sides will be the non-root bridges?  Would it be possible it configure them before they are deployed?  If so,  on the non-root bridges, would I put an IP on them both?  Or is the term "bridge" like any other bridge in networking, a dumb device?  I guess really what I want to know is how to configure the non-root bridges to ensure they will communicate with the root bridges before deployment.

[George Stefanick · Accepted solution]

No worries. We have all been there before.

YES. You need to configure these prior to install and do a few reboots to make sure everything comes up after a power cycle. You dont want to have to figure this out after installation . Also make sure you secure them properly.

Simple get 2 switches (one for either side) of the bridges. Config your vlans that you will use and make sure you can pass traffic from one side to the other.

Yes, if you have to use all 4 aps then you would have something like this... (see pix) that i just did...

Think of bridges like swicthes they are layer 2. The dont care at all about layer 3 IP. The only purpose for IPing a bridge is for managment (in almost all cases). Just like a switch, right ..

With that being said you need to consider your design and how you want to break up your network. Meaning do you put a router on either end of the bridge and route across the bridge or perhaps pull exsting vlans from the middle building to the side builds.

Make sense?

[George Stefanick]

Almost forgot are you using 2.4 or 5 Ghz for the bridge ? What yagi part number was ordered?

[jtadamofod81]

4 Antenna 16dBi Wireless Directional Yagi WiFi 2.4GHz. Cable to N-female (Not Cisco)

http://www.data-alliance.net/-strse-253/Antenna-16dBi-Yagi-Directional/Detail.bok

George, thank you again for your visual representations and insight.  You rule man.  It is actually a bit simpler, for it is all in one network (One subnet/no vlans).  I just want to make sure I get the correct Cisco vernacular,  the two slaves in your drawing will be the non-root bridges?  And the middle will be the root bridges?

[George Stefanick]

Correct, slave = non-root. And yes, the middle building are root(s).

I might suggest, you break up the domains. For exmaple, if a printer starts to broadcast (which printers do a ton) they will be sent over ALL bridges and then to ALL clients in ALL buildings. Although not knowing a lot about your install and client mix you may be fine.

if you find this helpful please kindly rate all helpful post!

Thanks!

[jtadamofod81]

Thanks again George,

This is just for a camera system. No users or printers will be joined in the non-root buildings.  I believe you have answered all my questions.  I will configure and post if any issues ensue!  Thanks again peoples!