Does what it says on the Tin!

I’ve had the pleasure to receive a new MacBook Pro for work, though I wasn’t particularly looking forward to the task of migrating all my data. I have to say Apple’s Setup Assistant has to be one of the most useful pieces of software ever! So far, the only casualty has been xchat. I remembered Bernard mentioned Babbel a while back, so I’ll give that a whirl instead.

Back up and running in less than 2 hours, thank you Apple!

SEMRA Training Weekend

As part of the requirements gathering process for the GAISS Project (Geograpically Aware Information Support System), which is an Enterprise Ireland funded, proof of concept phase project. Kristian and I spent last weekend as observers (mostly as observers, though the argo pictured below did get (ab)used for a short time) on an excercise run by the South East Mountain Rescue Association.

SEMRA Training Weekend - Galtees

This was to allow us to see both in practice and, later on Saturday, on paper, how their processes operate. To that end, we learned lots, and were completely exhausted by the end of the day.

Remarkably, all SEMRA personnel are volunteers, and give up much of their time in order to hone their search skills in order that you and I have some hope of survival if we get lost or injured on the mountains in the South East of Ireland. What is more remarkable still is how well organised and efficiently they operate given that they are so few in number and are all voluntary.

IEEE Podcast on Amateur Emergency Communications

The Institute of Electrical and Electronics Engineers (IEEE) feature Amateur Radio emergency communications in the October 2006 Spectrum Radio podcast which is available here.

Though US focused, it is interesting nonetheless. Personally I’m involved in the Amateur Radio Emergency Network (AREN) in Ireland which is Voluntary Emercency Communications arm of the Irish Radio Transmitters Society – IRTS.


Towards A Global Educational Network for Satellite Operations, or more succintly GENSO. More information is available here, but it looks like the ESA (and others) want to build a network of satellite ground stations distributed across the plannet.

It sounds very much like they have seen how distributed ground stations were used to good effect to gather telemetry from PCSAT2 (which is now back on earth). Where there was good use made of the APRS-IS backbone for carring the data. Though I have quite a modest set-up at home, I was even able to contribute data to the effort, so if the GENSO project is able to build on that experience, it should prove to be very effective. I wonder if I could get WIT involved, hmmmm….


I’ve been working quite a while now on the ENABLE project, specifically, we are looking at mobility protocols and evaluations of them. We have Mobile IPv6 running in the lab, and are currently working on building a Ubuntu LiveCD that is Mobile IPv6 Enabled. We are also looking at SHIM6 which, strictly speaking isn’t a Mobility protocol but a Multi-Homing Protocol. Thouth, in my (humble) opinion, in certain cases, there is little or no difference from the user perspective, but i digress.

Sébastien Barré has developed what he calls himself a “Pre-Alpha” implementation of SHIM6 available from I’ve been experimenting with it over the last week or so to see if I could get it working. In doing so I uncovered a subtle bug that took a bit of time for Sébastien and I to figure out (Credit to Sébastien).

Deliberately, we constructed identical set ups. Machine A with two ethernet ports (fec0::1, fec0::2), and machine B with one ethernet port (fec0::3). Sébastien was seeing correct behaviour, I was not (insert suitable expletives here!).

The correct behaviour would be to ssh to fec0::1 from fec0::3, disconnect the cable from fec0::1 and find that the session continues to work as normal (there is a 10 second delay for the protocol to spot that the connection has dissapeared, and for it to redirect the traffic). He was logging in using ssh and typing commands and it was all working fine. I was using scp and it wasn’t, then I logged in, ran ‘top’ and it still wasn’t, but strangely it was when I was just using single commands such as ls, df etc.

I’m still kicking myself for not spotting what was wrong sooner. Fair enough the code is pre-alpha, but roughly he is tagging the shim6 extension headers onto the TCP Packet. Using scp or top, the ethernet bursts are 1500 bytes long. His code sticks 8 bytes onto it and its now 1508 bytes long. Which means it breaks. My temporary solution is to run the command:

ifconfig mtu 1400

on every ethernet interface. Its working now (even Jerry H. was impressed), and rather than continue to hassle Sébastien, it might be time to start digging into code and attempt to fix it… god help us all!