Mercado Apartments - Nodes 3-4 Installation Report

Today volunteers from SoCalFreeNet got together and installed two new nodes at the Mercado Apartment complex. It was also a great training day, with three volunteers lending a hand for the first time. Many thanks to Ben, David, Doug, Drew, Jason, Marc and Pascal for providing their valuable time and expertise!

These two nodes are also a change for us. We had originally planned to simply repeat our node 1 and node 2 installations, but with new equipment coming onto the market all the time, and new software updates becoming available, we decided to try something new. Plus, we like experimenting! Go directly to the photos, or keep reading.

The result so far is very promising. Instead of spending an hour or more configuring pebble via ssh, and then repeating the installation for the second radio, we used the latest release of M0n0wall which now supports Atheros based radios, and hence the 802.11a component of our relay. Initial configuration took about 15 minutes and the second node took less than 5 as we could simply copy the single config file from one node to the other and adjust a couple of settings (wan static IP, WLAN subnet and DHCP range).

We're also using new hardware. WRAP boards have been around for a while, but we've used Soekris more often because of better availability and familiarity. However they are gaining increasing popularity with WISPs and we also obtained one and wrote about it in our recent book, so we were eager to try one. We've recently used Metrix kits instead of building our boxes because they're more convenient, well packaged and well priced. However the arrival of WRAP outdoor cases by Mini-box (see also our recent review) presents an alternative attractive solution. The bundle by Netgate is a convenient way to purchase this, except for the RP-N pigtails and 5 dBi antennas which we didn't use.

The topology of our network is a central 802.11a access point that is connected to the internet. From there we have several 'relay nodes' which receive the 802.11a signal and then supply internet via an 802.11b AP. The buildings at this particular site have walls that kill the 2.4GHz signal very quickly, so we need to have multiple access points even though the actual site size is relatively small. Click the map at right to see the node locations more clearly.

Each node runs in its own subnet and provides DHCP and DNS caching for local 802.11b clients. NAT (aka masq) is not done at the node location, but rather at the central gateway. Avoiding NAT at the node level will allow possibly future applications within the site, plus it allows the main gateway router to provide captive portal services for the entire network and generally centralizes management tasks. Read the network configuration for specifics.

The installation went smoothly. We started the day by reviewing and explaining the equipment in use and then stepping through the m0n0wall configuration we had used. All the equipment had been pre-assembled, mounted on the mast and tested first off-site and then onsite to help ensure that the day would go well.

Next we unpacked tools and lugged the gear over to the proposed location for node 3. Choosing the actual rooftop is a tradeoff between potential future growth of foilage, ease of access to the ground level utility cabinets where the power is and the coverage goals. And, to keep things interesting, it often isn't apparent until you actually get onto the rooftop whether or not a location will be suitable. E.g. for the second installation (node 4) we chose a rooftop from the ground, but then had to switch to an adjacent roof when we discovered intervening palm trees.

At this point we split into ground and rooftop teams. The roof team further split. Marc and Jason concentrated on mounting the radio. Pascal measured, cut and threaded the cat-5 cable and ground wire into conduit and fed it to ground level via the drainpipe.

The ground team took the drop from the drainpipe and routed it around to the utility closet using the flashing at the bottom of the buidling wall which had conveniently located holes for zip ties. The cat-5 cable went inside the utility cabinet to pick up the PoE power and the ground wire continued in the dirt to around to the large water pipe disappearing into the ground.

Click to view the photos below and the associated text with more information.

Equipment Costs

We haven't completed tallying up yet, but the approximate per node cost is $650. This breaks down as:

Cost	Item	Comment
$399	Netgate PowerG8 dual radio	or this plus this for $35 less (go figure?)
$28	2 x u.fl N-female pigtails
$36	2 x N-Male to N-Male cables
$45	802.11a panel	or a (better?) $40 dish
$20	lightning protector
$70	downtilt 802.11b 8dBi omni	or $40 for no downtilt
$20	mast and mount
$30	outdoor cat 5 + ground wire + fittings
$20	fudge factor

Overall, a pretty reasonable price. Just a year ago, this same functionalit cost almost $1000. And quite likely it will be closer to $600 before too long.

Mercado Network Current Status

Here is the current status of the Mercado network.

Node #3 and #4 installation, Friday March 3rd, 2005

Background

On Friday, March 3rd starting at 10am, we will be installing the 3rd and 4th nodes at the Mercado Apartments (directions) in Barrio Logan. On previous project days, we have installed an 802.11a AP on the rooftop of the manager's office and also an 802.11a bridge/802.11b AP on the farthest building.

For more details on previous installs, see: main AP, node 1 and node 2 installation reports.

Project Objectives

The function of Node #3 and Node #4 will be to extend the wireless cloud inside the Mercado apartment complex. The addition of these two nodes should largely complete the installation. Further testing will follow to determine if another node is required.

Technical Solution

We'll be adding nodes 3 and 4 as described in the network configuration.

We will install Netgate WRAP based hardware. This device uses an Atheros a/b/g radio which we will use (in 802.11a mode) for the backhaul, as well as an 802.11b Intersil Prism 2.5 radio which we will use for client access.

For software, we will be using the latest M0n0wall release, beta version (1.2b6) which now supports the Atheros chipset. This will be our first attempt to use M0n0wall in a relay/bridge mode and we are very excited about its potential use in this capacity for future deployments.

Install Plan

We have 2 nodes to install, therefore we will need two teams to perform identical tasks. First, we will be attaching all of the devices to the antenna mast and mounting the mast to the rooftop. Next, we will run cat5 down the side of the building to a PoE injector located in the utility closet. Next, we will install a lightning arrestor and run grounding cable. If we cannot find a suitable grounding point, then we will install a grounding rod. Finally, we will perform QA/Safety/Regulatory Compliance checklists to ensure a proper deployment.

Day of Install Tasks:

Volunteer 1 (Team 1: Michael, Team 2: ?)
- Prepare mast assembly (attach antenna / lightning arrestor / waterproof putty)
- Install mast and secure to building with mounting bracket

Volunteer 2 (Team 1: ?, Team 2: ?)
- Run grounding wire, find (or build) appropriate grounding point
- Run Cat5 along roofline
- Crimp Cat5 heads (terminate cables w/RJ45 jacks)

Volunteer 3 (One Volunteer for both Teams: ?)
- Perform QA / Safety checks, complete checklist

Folks who've volunteered so far: Neven, Eric, Jason, Doug (EC: see private pages for full contact info)

Budget:
- Insert costs here

Pilot Installation at Barrio Logan Mercado site

Today some SoCalFreeNet volunteers went to the Mercado site in Barrio Logan. We've been there several times before at the request of the MAAC project to explore providing free wireless internet access to their residents and the surrounding community.

Today, our goal was to get some actual real-world equipment onto a rooftop, and ideally leave with one building online. We planned to do this by:

1. Put an 802.11b AP on a rooftop and measure coverage as much as possible without actually getting inside (unless a resident happened to be around to let us in).
2. Determine if an 802.11a backhaul link would work, despite not quite line of sight due to some and intervening trees. For this, we picked the furthestmost rooftop.
3. Try to hook the link and AP into the existing DSL connection in the main office so people could start using it.

We managed to achieve our first goal, despite a few obstacles along the way (e.g. it initially looked like we wouldn't be able to get power to the rooftop). And, best of all, we discovered that, unlike easlier site surveys, it seems that we might be able to cover four buildings per AP, instead of the 1-2 buildings we'd estimated. We'll know for sure after we've had a chance to get inside and/or get some residents online.

We're going to go back tomorrow to finish goals 2 and 3. We did make good progress on 3, as it appears we can pull the signal off an existing 802.11b wireless AP in the office using one of our standard client kits.

M0n0wall installation at Mercado Wireless Network

We have a multi-node wireless network installed in a 144 apartment complex with 24 buildings. The one router that binds and rules them all is currently running m0n0wall. This article describes the configuration of the network as a whole and m0n0wall specficially. There were a number of gotchas involved in setting this up, so I lay them out here here in the hope it will save others some time.

Each node in the network resides in its own /27 subnet (full addresss details) and has its own dhcp server and DNS cache. All nodes route to one master node in a classic "star" point to multi-point configuration.

The master node in turn connects to the gateway node which is connected to a DSL modem using PPPoE for its connection. The gateway node also provides DHCP and NAT services to local office computers and a computer lab.

M0n0wall Gateway router Configuration

The gateway router has to provide the following services:

• PPPoE connection management
• local office subnet DHCP, NAT and firewall
• wireless network NAT, captive portal and firewall
• firewall between the office and wireless networks
• wireless link to master node

In addition the following features are nice to have:

• secure outside administration
• offsite syslog reporting
• remote IPSEC / PPTP access
• Dynamic DNS updating so we could admin the router using a web address

M0n0wall provides the capabilities to do all this (and more).

to be continued - a work in progress