Category Archives: Work

IPv6, Work

SHIM6

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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 http://gforge.info.ucl.ac.be/projects/shim6. 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!

Travel, Work

Shanghai Maglev

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It looks just like any other Train initially.
Maglev Train Shanghai

The Track is different:
Maglev Train Shanghai

Holy smokes this IS quick:
Maglev Train Shanghai

I think it took about 5 minutes and 20 seconds to cover the 30 Kilometers to the Airport. Pity we couldn’t have one running from Waterford to Dublin Airport!.

Travel, Work

Taxis

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On entering a Taxi, we were normally greeted by a recorded English announcement helpfully telling us to put on our seatbelts. But its impossible, the belt is trapped behind the seat, and the buckle is somewhere under the seat. Once you start moving you realise there is something different. Driving in Shanghai is a ‘might is right’ type of experience, or maybe ‘who dares wins’. A Horn is not optional. Its used to warn others that you are coming through without stopping (those pesky pedestrians that cross when the green man is on), and that they had better get out of your way. Or it is used to tell the bicycle/moped/car to get out of the way. Headlights seem to be used for the same function as well.

Indicators are optional, though they do get used now and again. Lane markings are just a general guideline, red lights are a mystery. I can’t figure out why they stop and some red lights and not at others. However, with all the hornblowing and flashing of lights and general chaos there doesn’t seem to be any road-rage, (its not personal), and they seem not to tail-gate.

Anyways, Saturday night in shanghai, we were trying to re-adjust to Irish Time, so we decided that there was no better way than to stay up late, we headed for the Jin Mao Tower for a drink, and a view. The bar, Cloud 99, is the highest bar in the world apparently.

Shanghai at Night

We were able to see Clouds passing outside while sitting there drinking our chosen poison. As well look out over Shanghai at the Oriental Pearl Tower. Great view!

Shanghai at Night

Travel, Work

Shopping

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The markets here are really interesting, lots of stuff on offer. The three most common items seem to be watches, bags or dvds. The buying process is interesting as well. It is expected that you will haggle, for example, we went to purchase one item, the initial price was 850 Yuan, we left the shop with it for 150 Yuan.

What really surprised us was that it is possible to haggle in the Department Stores, now whether the money is actually going into the till or not is a completely different matter.

Bookmark, Work

Missed it

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It, being the official opening of our building. Feedback I’m getting is that it was all good, if a slightly short visit by An Taoiseach.

We continue to work through the different workpackages, slower than I would prefer, but I’m not the chairperson, so its not up to me.

Miguel and I provided free entertainment for a restaurant full of punters last night. When we returned from the days meeting, we just walked a block or two to find a restaurant. Things looked promising as it had the name in English, better yet, the menu had English discriptions as well. So we ordered something, but we really weren’t quite sure what. The waitress arrived back to the table with a big pot (various joints of beef, knee’s etc, carrots and some thick noodles), stuck it on a gas burner (in the middle of the table), wandered off again, and then came back with raw meat and veg and plonked it on the table beside us.

What we didn’t know was that we are suppossed to cook it ourselves. Obviously the waitress had a bit of a chat with her co-workers and they decided that if they didn’t do something we would be there for hours. So this poor girl started cooking and showing us how we were supposed to cook the food. This caused much amusement in the restaurant. We got the hang of it eventually (rice noodle not withstanding).

I think she was a bit shocked with the amount of the tip we left, but she did help us out . Total cost for dinner including two beers (640ml bottles, must figure out why that is.) and the tip, €12.

Bookmark, General, Work

Work begins today

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Yesterday, we decided to go out and about to get as much sunlight as possible in order to recover from jet-lag. It was difficult to get up this morning, but we managed. After breakfast we headed for the science museum, as it was quite close. Unfortunatly it was closed. After a quick discussion, we decided to head to the Oriental Pearl TV Tower, where we had lunch, then to the Jade Buddha Temple were we watched a craftsman at work.
craftsman at work

Today, work begins. We are here for a meeting of the Enable project, that we are working on in the TSSG. It will be 3 days of powerpoint, discussion, argument, more discussion, argument and hopfully, consensus, as to the continued direction of the project. Also, it is an opportunity to meet the partners again face to face, and continue to build working relationships with our project partners.

Bookmark, General, Work

34 hours

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Something along the same vein as Bernard’s piece. We arrived in the airport, immigration cards filled in, only to get stuck in the queue behind a group of American’s who obviously hadn’t filled theirs in properly (and at that point it was too late to change our queue). In fairness to the officials, they did begin opening up more gates as the passengers were getting more and more frustrated, and finally we (Miguel and I) were free (or so I thought).

“We just need to check something, it won’t take long”

For somewhere between 10 and 15 minutes I was standing beside the passport control desk, positive that I was going to be on the next flight home, as other passengers were nervously going past me. Finally my passport was delivered back to the control desk (and to me with no explanation) and I was let through (phew!).

We were having a good laugh about it while we were filling the ‘baggage declaration’, when Miguel noticed one of the questions asks “Do you have any Radio Transmitting or Receiving equipment”. BALLS! As I normally carry a VHF/UHF handheld Transciever in the laptop bag, I didn’t relish the thought of being asked to ‘step aside’ for a second time (I had great visions going through my tired brain after about 27 hours travelling). Thankfully I had seen the good sense to take it out before heading for the airport in the first place.

We found our hotel and set about wandering around the city with the sole purpose of getting lunch, and attempting to stay awake as long as possible. After getting a fantastic pizza (hunger is a great critic!), and been offered everything from “Cheap” Watches, Cameras, Hash and other stuff that I won’t go into (I must look more dodgy than Miguel, I seem to get more offers, but who’s counting?)

It’s been over 34 hours now, thats about how long it is since I got out of a bed (Thanks again Mr. & Mrs. K) to head to Cork airport, now I’m about to get back into a bed again (in Shanghai), and I’m really looking forward to getting some sleep, I’m shattered.