Related work: Market Contact Protocol

An interesting Master's thesis called "Content Sharing for Mobile Devices" has an extremely comprehensive and complete look at the problem of finding and sharing content with other local mobile devices.

The thesis has excellent documentation comparing DHTs, overlay networks and other related work in this field.

The simulation and datasets in the thesis are also very comprehensive, and may be helpful if we ever do a simulation ourselves in this field.

The implementation itself, a protocol called "Market Contact Protocol" - at first glance - seems very similar to what we are doing with the BonAHA project, and related work such as LightPeers.

Wireless cards, antennas and connectors

Today I hunted down a wireless antenna-cable combo to go with our wireless card, the Atheros-based Gigabyte GN-WIAG02.

I didn't realize that there were different forms of cables and antenna for wireless cards, so I had to learn more about these.

I found out on Hyper Link Tech that there are several types of these. Because the Gigabyte card is a 802.11 b/g, which runs on the 2.4GHz frequency, what I needed was a 2.4 GHz rubber duck antenna. 5 dBi seems to be fine for the WORKIT testbed.

There were some helpful pages on gumph.org and Seattle Wireless that helped me find out more about the antenna, cables and connectors that are needed for wireless.

It appears that the most common connector for the miniPCI based wireless cards is the MMCX connector.

Finally decided to get the AOpen wireless antenna, which appears to have the antenna as well as the cables needed to fit the antenna onto the kit.

Setting up a Linux AP: Bridge vs. router

Now that I have DHCP and DNS set up, the last thing I need to do is set up the WORKIT box to act as a complete AP by bridging the wireless (LAN) and wired (WAN) connections.

I naively followed linux.com's instructions on setting up a wireless AP by bridging the connections.

I was surprised to see that it completely broke the DHCP/DNS/gateway system I had set up - my wireless client instead picked up the IP address (DNS and DHCP) from the department's regular network. And my "gateway" (the WORKIT AP) had "disappeared", since I was not being assigned an IP address from it and was not on its internal network (10.0.0.x) that I had set up.

What had happened? I finally realized I had set up Linux on the WORKIT AP as a glorified wireless bridge (think switch/hub), not a router!

What I now need to do is set up Linux to act as a gateway, so the WORKIT AP acts completely as a full AP.

A little more search leads to YoLinux's article on setting up a Linux gateway and on Linux Journal as well. Basically, this involves a little fiddling around with iptables...

Drill Bushings from McMaster-Carr for WORKIT Soekris

Hi, I'm back after a long while ... decided to continue using my Blogspot account for work related blogs, while the CS@CU wiki can remain as a wiki for official documentation.

Today, I was looking at finding ways of getting washers/bushings to seal off the Demarctech hardware that encloses our Soekris net5501 box. Talking to George at the machine shop indicates that McMaster-Carr would be the best source of such bushings.

I think I am looking for the items under :
Machining and Clamping > Drill Jig Bushings > Drill Bushings and Liners > Drill Bushings for Soft Materials

More to come soon ... as soon as I figure out exactly what I need.