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Collegiate:
No

One-line Description:
Appliance to bridge wireless network to wired network

Filename:
bridge.zip

Size Compressed:
46MB

Allocated Memory:
24

Username:
na

Password:
na

VMware Tools Installed?:
No

Operating System:
Linux (Knoppix) 2.4

Applications:
bridge-utils 1.0.4-1 and dependencies

Description:
Over 1 year ago I needed to create a wireless bridge on PC hardware, due to the failure of an expensive dedicated bridge device and it’s attempted replacement by a cheaper, but underpowered device. Logically this would be built using Linux with the bridge utilities installed. Through all of my testing on both PC and PDA hardware I was not able to bridge a wireless adapter natively in Linux. I would create the bridge and add the interfaces, the command “showmacs” verifies that it sees nodes in both directions, but it does not pass traffic. The following article seems to explain why it can’t be done: http://linux-net.osdl.org/index.php/Bridge#It_doesn.27t_work_with_my_Wir...
I had set out to build a wireless bridge appliance natively but could only accomplish this using the unique characteristics of VMware.
The VMware virtual network presents a bridgeable NIC to Linux, which makes the bridging utilities work as expected, and a Linux VM can then act as the bridge between two unbridgeable adapters on the host. When built on an older, decommissioned PII laptop you have an inexpensive and quickly deployable solution with many advantages over a hardware counterpart. You may use ANY wireless NIC with NT drivers, and choose the appropriate RF power and/or connector to match your antenna. Laptops usually have both a battery and a modem, with obvious benefits for a critical connection. You may add a third USB NIC for management.
Laptops also have IR and serial. If your hardware allows, you may run other software on the host, for antenna control, packet sniffing, wireless connection tuning, security, etc. This could also be a free temporary solution to get the link up immediately. ISP’s with wireless customers typically place a wireless bridge at each customer site, and usually the expensive ones. This appliance can be remotely managed more intimately than bridges costing $600+. Or maybe you just want to use a hotspot without sitting on the windowsill.
This virtual appliance was born out of necessity, over 1 year ago.
I access my ISP via 802.11b wireless to an access point 7.5 miles from my home. This was originally done with a 24dbi parabolic grid on a 75’ tower connected with LMR 600 to a wireless bridge with a 100mw card, and cat5 to a router in the house. After numerous problems with moisture in the dish, my ISP gave me a smaller 15dbi dish and a 200mw card to install in the bridge. Soon after, the bridge died and they gave me a WET11, which was their new standard setup. A WET11 is not even the 100mw I used to have, so a significant drop in performance was the result. They had no more bridges but let me keep the 200mw card.
I attempted to build a bridge natively under Linux using various hardware, with no success. I thought of using VMware while trying to add bridging to some pre-built firewall ISO.
Using VMware it was almost too easy. I put Microsoft Windows XP on a junky 300Mhz PII laptop with 192MB and a line down the screen. I added Xplite ( http://www.litepc.com/xplite.html )to make it more secure and efficient, and VMware Workstation 4.5. The VM had 128MB, no hd and booted from a Knoppix STD ISO. I configured the bridge and took a snapshot. On the 4 occasions it needed a reboot, I resumed the snapshot and saved the typing. This has been very reliable for over a year, sitting in a Lowes PVC garden shed.
Although this is certainly usable, it was not ready for the virtual appliance challenge or MAKE magazine or anyone else at this point.
I re-mastered MiniKnoppix down to a 22MB LiveCD, and the bridging is now scripted. The VM needs only 24MB to run, so maybe 128M is the minimum on the host. VMware tools is not appropriate here and is not installed.
So you have some laptop with MS Win XP, at least 128 MB ram, 1 802.11x NIC and 1 Ethernet NIC.
Install your chosen VMware product, aim the wireless NIC at Vmnet2 and the wired one at Vmnet3 in the virtual network editor. Open the VM I have included in the zip. Setup your wireless connection to work across boots. Set the VM to power on at host startup. Select bridge.iso or bridge_stp.iso as appropriate and boot. Verify forwarding. Bridge.doc is included as a "readme" for this Virtual Appliance.

Technical Specifications

Operating System:

Linux (Knoppix) 2.4

VMware Tools installed: No

Size: 46MB

Allocated Memory (RAM): 24

Applications Installed:

bridge-utils 1.0.4-1 and dependencies

Virtual Appliance Account Information