When introducing data communications concepts and protocols to students I think it is beneficial to demonstrate, and more importantly, allow students to play with real protocols. In the lab I teach (ITS332), as well as assignments for some lecture courses, we use Wireshark to capture traffic generated by several Internet applications (e.g. ping, Secure Shell, web browsing, iperf). This allows students to see the actual packets being sent across a network, and start to understand the protocol rules and formats used.

Unfortunately sometimes what we see in Wireshark is not what we expect. One case in which this occurs is when TCP/IP operations are offloaded by the operating system to the Network Interface Card (NIC). Common operations for offloading are segmentation and checksum calculations. That is, instead of the OS using the CPU to segment TCP packets, it allows the NIC to use its own processor to perform the segmentation. This saves on the CPU and importantly cuts down on the bus communications to/from the NIC. However offloading doesn't change what is sent over the network. In other words, offloading to the NIC can produce performance gains inside your computer, but not across the network.

How does this affect what Wireshark captures? Consider the figure below illustrating the normal flow of data through a TCP/IP stack without offloading. Lets assume the application data is 7,300 Bytes. TCP breaks this into five segments. Why five? The Maximum Transmission Unit (MTU) of Ethernet is 1500 Bytes. If we subtract the 20 Byte IP header and 20 Byte TCP header there is 1460 Bytes remaining for data in a TCP segment (this is the TCP Maximum Segment Size (MSS)). 7,300 Bytes can be conveniently segmented into five maximum sized TCP segments.

After IP adds a header to the TCP segments the resulting IP datagrams are sent one-by-one to the "Ethernet layer". Note that TCP/IP are part of operating system, while most functionality of Ethernet is implemented on the NIC. However network drivers (lets consider them part of the OS) also perform some of the Ethernet functionality. The network driver creates/receives Ethernet frames. So in the above example, assuming segmentation offloading is not used, the 7,300 Bytes of application data is segmented into 5 TCP/IP packets containing 1460 Bytes of data each. The network driver encapsulates each IP datagram in an Ethernet frame and sends the frames to the NIC. It is these Ethernet frames that Wireshark (and other packet capture software, like tcpdump) captures. The NIC then sends the frames, one-by-one, over the network.

Now consider when segmentation offloading is used (as in the figure below). The OS does not segment the application data, but instead creates one large TCP/IP packet and sends that to the driver. The TCP and IP headers are in fact template headers. The driver creates a single Ethernet frame (which is captured by Wireshark) and sends it to the NIC. Now the NIC performs the segmentation. It uses the template headers to create 5 Ethernet frames with real TCP/IP/Ethernet headers. The 5 frames are then sent over the network

The result: although the same 5 Ethernet frames are sent over the network, Wireshark captures different data depending on the use of segmentation offloading. When not used, the 5 Ethernet frames are captured. When offloading is used, Wireshark only captures the single, large frame (containing 7,300 bytes of data).

To further illustrate segmentation offloading, and how to control it in Linux, consider the following tests performed on two Ubuntu computers, basil and ginger, connected on an Ethernet LAN. On basil (which has IP address 10.10.1.22) netcat in server mode is used to receive data:

sgordon@basil$ nc -l 5001

On ginger netcat in client mode is used to send 10,000 Bytes of data (stored in a file) to the server.

sgordon@ginger$ nc -p 5002 10.10.1.22 5001 < 10000bytes.txt 

tcpdump is used to see the captured IP packets, and in particular the size of the TCP segments. I could have used Wireshark, but the text output of tcpdump> is easier to include in this page. ethtool is used to view and change the status of segmentation offloading (in this example, generic segmentation offload or GSO).

First note that ethtool shows us that generic segmentation offload is on.

sgordon@ginger$ sudo ethtool -k eth0
Offload parameters for eth0:
Cannot get device flags: Operation not supported
rx-checksumming: on
tx-checksumming: on
scatter-gather: on
tcp segmentation offload: off
udp fragmentation offload: off
generic segmentation offload: on
large receive offload: off

Now, after running the netcat client, lets see the output from tcpdump (for clarity I have omitted the option fields from selected TCP segments):

sgordon@ginger$ sudo tcpdump -i eth0 -n 'not port 22'
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 96 bytes
18:30:24.899687 IP 192.168.1.2.5002 > 10.10.1.22.5001: S 679249855:679249855(0) win 5840 
18:30:24.900583 IP 10.10.1.22.5001 > 192.168.1.2.5002: S 1420594303:1420594303(0) ack 679249856 win 5792 
18:30:24.900612 IP 192.168.1.2.5002 > 10.10.1.22.5001: . ack 1 win 92
18:30:24.900713 IP 192.168.1.2.5002 > 10.10.1.22.5001: . 1:2897(2896) ack 1 win 92
18:30:24.900735 IP 192.168.1.2.5002 > 10.10.1.22.5001: . 2897:4345(1448) ack 1 win 92 
18:30:24.902575 IP 10.10.1.22.5001 > 192.168.1.2.5002: . ack 1449 win 68 
18:30:24.902591 IP 192.168.1.2.5002 > 10.10.1.22.5001: P 4345:7241(2896) ack 1 win 92 
18:30:24.903597 IP 10.10.1.22.5001 > 192.168.1.2.5002: . ack 2897 win 91 
18:30:24.903607 IP 192.168.1.2.5002 > 10.10.1.22.5001: . 7241:8689(1448) ack 1 win 92 
18:30:24.903613 IP 192.168.1.2.5002 > 10.10.1.22.5001: P 8689:10001(1312) ack 1 win 92 
18:30:24.903617 IP 10.10.1.22.5001 > 192.168.1.2.5002: . ack 4345 win 114 
18:30:24.905573 IP 10.10.1.22.5001 > 192.168.1.2.5002: . ack 5793 win 136 
18:30:24.905587 IP 10.10.1.22.5001 > 192.168.1.2.5002: . ack 7241 win 159 
18:30:24.906628 IP 10.10.1.22.5001 > 192.168.1.2.5002: . ack 8689 win 181 
18:30:24.906637 IP 10.10.1.22.5001 > 192.168.1.2.5002: . ack 10001 win 204 

Each line is showing a captured packet. The TCP segments containing data can be identified by the sequence numbers (I've made them bold). The number in parentheses indicates the number of bytes in this TCP segment. We can see from the capture that our 10,000 Bytes of data is broken into 5 segments containing: 2896, 1448, 2896, 1448, 1312 Bytes each. But wait ... 2896 Bytes in a TCP segment when the MSS is 1460? (in fact, with TCP header options, like SACK and timestamp, the MSS in this capture is 1448). This is Generic Segmentation Offloading going to work: the OS is sending large segments, as captured above, and letting the NIC do the real segmentation.

So now lets turn Generic Segmentation Offloading off using ethtool:

sgordon@ginger$ sudo ethtool -K eth0 gso off

And run the netcat transfer again and look at the tcpdump output this time:

sgordon@ginger$ sudo tcpdump -i eth0 -n 'not port 22'
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 96 bytes
18:33:02.644356 IP 192.168.1.2.5002 > 10.10.1.22.5001: S 3144010294:3144010294(0) win 5840 
18:33:02.645427 IP 10.10.1.22.5001 > 192.168.1.2.5002: S 3901655238:3901655238(0) ack 3144010295 win 5792 
18:33:02.645471 IP 192.168.1.2.5002 > 10.10.1.22.5001: . ack 1 win 92 
18:33:02.645542 IP 192.168.1.2.5002 > 10.10.1.22.5001: . 1:1449(1448) ack 1 win 92 
18:33:02.645558 IP 192.168.1.2.5002 > 10.10.1.22.5001: . 1449:2897(1448) ack 1 win 92 
18:33:02.645567 IP 192.168.1.2.5002 > 10.10.1.22.5001: P 2897:4345(1448) ack 1 win 92 
18:33:02.647415 IP 10.10.1.22.5001 > 192.168.1.2.5002: . ack 1449 win 68 
18:33:02.647433 IP 192.168.1.2.5002 > 10.10.1.22.5001: . 4345:5793(1448) ack 1 win 92 
18:33:02.647439 IP 192.168.1.2.5002 > 10.10.1.22.5001: . 5793:7241(1448) ack 1 win 92 
18:33:02.648437 IP 10.10.1.22.5001 > 192.168.1.2.5002: . ack 2897 win 91 
18:33:02.648446 IP 192.168.1.2.5002 > 10.10.1.22.5001: . 7241:8689(1448) ack 1 win 92 
18:33:02.648451 IP 192.168.1.2.5002 > 10.10.1.22.5001: P 8689:10001(1312) ack 1 win 92 
18:33:02.648460 IP 10.10.1.22.5001 > 192.168.1.2.5002: . ack 4345 win 114 
18:33:02.650414 IP 10.10.1.22.5001 > 192.168.1.2.5002: . ack 5793 win 136 
18:33:02.650428 IP 10.10.1.22.5001 > 192.168.1.2.5002: . ack 7241 win 159 
18:33:02.651469 IP 10.10.1.22.5001 > 192.168.1.2.5002: . ack 8689 win 181 
18:33:02.651476 IP 10.10.1.22.5001 > 192.168.1.2.5002: . ack 10001 win 204

Now this is what we expect to see - 7 TCP segments each no larger than 1448 Bytes.

Whats the conclusion of all this? What is taught in lectures and textbooks is not always what you see in practice. I suggest turning offloading optimisations off to demonstrate the basic concepts, and then turn them back on again to illustrate the practical performance optimizations applied at the expense of theoretical layering principles.

Its always nice to see and deal with other people using Unix-based operating systems. If a student comes to me for help with a software problem, although I'll try to help no matter what OS, I am much more interested in spending time with them if they are using a Unix-based OS (Ubuntu, MacOS, etc). This is mainly because that is what I know best. Of recent, more students have Ubuntu installed, either as dual-boot or in a virtual machine, on their personal laptops. And they are starting to learn that the Windows GUI way is not the only way. I am encouraging the further exploration of Linux in my networking lab (ITS332) where 90% of the tasks are completed on the command line in Ubuntu (the other 10% using Wireshark in Ubuntu). In other courses, although I don't require the students to use any specific operating system, I demonstrate how easy it is to complete networking tasks in Unix-based OSes, such as measure the throughput of TCP in a network with varying packet loss rates (three command line operations using iperf and tc).

One of the local Unix gurus at SIIT is Yoichi. As well as doing his research, he has been active in labs and teaching introductory computing to SIIT/Thammasat students. He has started to blog about some of the simple, yet very powerful things that can be done via the command line in Ubuntu. Yoichi and other teaching assistants and graduate students are spreading the word in SIIT that Windows is not the only operating system available. And their efforts are starting to show as more students are coming to me for help on a network or programming assignment with their laptop booted into Ubuntu.

CPN Tools is a popular software application for creating, simulating and analysing Coloured Petri Nets. I've used it occasionally over the past 3 or 4 years, and also used its predecessor, Design/CPN, extensively during my PhD. There has always been a Linux and Windows version of CPN Tools, however the GUI in the Linux version has some bugs, and the developers have decided to concentrate only on the Windows GUI for future releases. Thats annoying for me, however all is not lost as the simulator process of CPN Tools (for simulations and state space analysis) will still run in Linux. That is, the GUI can run on one host, and it communicates via TCP/IP sockets to the simulator on another host.

With the current external version (2.2.0) I had trouble setting up the remote simulator, but after trying with the latest internal version (2.3.5) I worked it out. There are some instructions spread across different posts in the Support Maillist, but for reference I give the precise commands I used here. The instructions are for running both the GUI and simulator under Linux, but can be modified for any combination of Windows and Linux. It turns out the version of CPN Tools didn't make any difference - these instructions will work for both versions 2.2.0 and 2.3.5. (2.3.5 also provides an option in the GUI to set the remote simulator, but I didn't use that).

Install CPN Tools on both hosts, in the directory /home/user/CPNTools/. On the host that will run the simulator with example IP address 10.10.10.1, change into the install directory and run:

./cpnsim/cpnmld 7001 cpnsim/run.x86-linux

7001 is the example port number the simulator will listen on. You may choose another value (so long as it is not in use by another application. If you wanted to run the simulator under Windows, then replace run.x86-linux with run.x86-win32.exe (and of course use backslash instead of forward slash).

On the host that will run the GUI with example IP address 10.10.10.2, change into the install directory and run:

./cpntools -remote -image cpnsim/cpn.ML.x86-linux -port 7001 -host 10.10.10.1

Of course set the host IP address to the actual IP address of your simulator host and use the appropriate port number.

On the GUI host you should see output such as:

INFO: Using remote simulator (UNIX)

and the CPN Tools Gui should start. You can now open a CPN file. Once opened, on the simulator host you should see output such as:

Accepted connection from 10.10.10.2
login = cpn2000
path = ./
User login
Starting new session for user cpnsim/cpn.ML.x86-linux in ./
Starting new session
Child spawned with pid = 24935

Changing current path to ./
Executing: cpnsim/run.x86-linux @SMLload=cpnsim/cpn.ML.x86-linux @SMLcmdname=cpnsim/cpn.ML.x86-linux
GC #0.0.0.0.1.6:   (0 ms)
GC ...

and the GC output will continue as the simulator checks the syntax.

This looks, and is easy. However it took me several hours to get it working. When opening a net I would get an error in the GUI: a red popup box saying something like "Could not start the simulator. You will not be able to simulate the net". It turned out my most significant problem was the permissions of my install of CPNTools on the simulator. All files were owned by the normal user except cpn.ML.x86-linux which was owned by, and only had read permissions for root. After changing the ownership/permissions of this file to be the same as all others, everything worked. I'm not sure what lead to this situation, but hopefully now others will not make the same time-wasting mistake as me.

New Years Eve 2009 was spent around Wan's family home in the north-east. We left Bangkok about 2am on Tuesday 29 December with the intention of avoiding the traffic jams seen last year. It worked - there was almost no traffic, even less than normal. It took 6 hours to drive to her home, which is midway between Chumphae in Khon Khaen and Phu Kradeung in Loei (normally it takes about 7 hours, although we didn't stop for food so much this time).

Apart from relaxing and catching up with family and friends (Ann, Wan's sister, and her husband Simon were also there) we had a few day trips to: Nam Nao National Park in Petchabun, a local mountain, Phu Pa Man, and near Phu Luang in Loei. As always, a lot of good food and a few beers. New years eve involved a party with a lot of family attending, followed by some late night dancing at a street party. All good fun.

The trip home on Sunday was not too bad. It took 9 hours, which was probably 1 or 2 hours less than it could have been because we took a back route to Saraburi, bypassing the busy Khorat to Saraburi road.

Check out some photos.

The CABINN Hotel was recommended to participants of the CPN Workshop. It is part of a chain of 6 or 7 CABINNs across Denmark. They have the aim of the providing cheap but comfortable accommodation near the centre of the city. The tradeoff is the room sizes. They follow the layout of cabins in cruise ships; small and with bunk-beds.

The hotel is about 10 minutes walk, straight along the main shopping mall, from the Arhus central station (where trains and the airport bus stop). The area between central station and the hotel is the main (only?) area for shopping, pubs, restaurants and night-life in Arhus. So the location of the hotel is great.

I arrived at 1pm, and despite the hotel web site saying checkin was between 3pm and 6pm, I was immediately given a room. As expected, it was small. There was a single bed, and a bunk-bed above it. There was a desk, small TV, electric kettle and small bathroom containing toilet, shower and sink. There were 3 or 4 coat hangars and a couple of shelves to store clothes. The room size was not a problem for me. However if there were two of you with full size suitcases you probably would find it too small. Of course there are a few larger rooms at the hotel.

Despite the small room sizes, the rest of the hotel is quite good. The lobby is large with a couple of sofas, and then there is a TV lounge with 5 sets of tables and chairs and a LCD TV. On the 4th floor is the breakfast room which was great. Each morning there were fresh loafs of bread, bread rolls, bread for toasting, to be accompanied by cheese, slices of ham/turkey/salami and 3 or 4 delicious jams. There were 3 types of cereal, milk and yogurt and of course, coffee, tea and juices. It wasn't fancy but it was more than enough to get you full in the morning. I loved the fresh bread with salami and cheese, and made about 3 slices each morning. There is a restaurant/cafe on the bottom floor but I never went there (not sure if it is just part of the hotel or on fact an external restaurant). Finally, the reception sells snacks and drinks 24 hours a day (a bottle of Tuborgs beer was 27 Kroner).

The room price was 465 Kroner plus 60 Kroner for breakfast; a total of 525 Kroner per night. I think this was a discount of 20 Kroner per night (as we booked as part of the CPN Workshop group). As Denmark is one of the most expensive countries in Europe, I consider this price quite good value and would recommend others to stay there (unless they need a large room).

I have been getting back into some Petri nets research recently, and to catch up on the latest happenings with Coloured Petri nets I submitted a paper to the CPN Workshop in Arhus, Denmark. The paper was accepted and tomorrow I leave for a week in Aarhus.

This is the 10th CPN Workshop, all held in Arhus (the home of the people who created CPNs and the related software tools like Design/CPN and CPN Tools). It turns out the first time I ever presented a research paper was at the 1st CPN Workshop in 1998. So I have been to Arhus before (twice) and am looking forward to catching up with colleagues and friends.

Wan was in search of a netbook for use at home and work, so after a couple of days online and wandering around Zeer Rangsit IT Plaza, she finally settled on the Samsung NC 10. It looks good, has a nice sized keyboard, received good reviews online, and was priced well against other netbooks (Asus, Acer, Lenovo, Dell, etc.).

The specs are about the same as equivalent class netbooks from other companies:

• Atom N270 processor
• 1GB RAM, easily upgradeable to 2GB if needed
• 10.1inch screen
• 160GB hard drive
• IEEE 802.11b/g, Bluetooth, 100Mb/s Ethernet

The final price was 12400 Baht, which included an external DVDRW drive (which has yet to arrive).

As Wan has been using Ubuntu on my home PC for a while, the first thing I did with the netbook was install Ubuntu Desktop 9.04. I overwrote the existing Windows XP Home install, which I didn't think there would be any use for (However, I latter regretted this - I should've left it dual-boot. It turns out to update the laptop BIOS, Samsung software must run under Windows. Oh well, if an update is really needed it won't be too hard to backup Ubuntu and install Windows from the recovery CD).

I've had a few hours of setting it up and using it, and so far it seems like a good buy. The main thing I need to learn about is the Ubuntu power management features, where some fine-tuning is needed to conserve battery but also give reasonable (and constant) brightness settings.

Some sites with info on the Samsung NC10 and Ubuntu include:

• Samsung NC10 at Wikipedia
• SammyNetbook
• Ubuntu NC10 Community page
• Ubuntu on the Samsung NC10

Since returning from a holiday in Australia in April not much has been happening other than work. However over the past semester I finally made the switch to Ubuntu on all my computers.

In fact I have been running Ubuntu on all my computers since moving to Thailand. Both my home PC and work PC were running dual boot Windows XP and Ubuntu Desktop, and my home Pentium III web server Ubuntu Server. I was using Windows for most of my work. However when my own server PC died I shifted to running Ubuntu full-time on my main home PC (acting as my web server and everyday PC), and a month ago I deleted the Windows partition (but have XP installed under VirtualBox). At work I haven't got around to deleting XP, but I only use it a few hours per week.

Ubuntu supports almost everything I need for my everyday computing activities at work and home: browsing, office applications, graphics, watching movies, occasional basic games. Of course it also perfect for hosting my web and email server. The only things I've been needing Windows for are: running some Windows-only simulation software, opening/editing old documents in MS Office (most of my old lecture slides were developed in Powerpoint - OpenOffice Presentation doesn't always handle the animations and fonts), and accessing web sites of selected financial institutions (IE only). Now all new work documents are created in OpenOffice. Slowly I am converting old documents, especially teaching material, to OpenOffice formats. It is a nice feeling knowing that eventually my 1000's of pages of teaching material will soon be in open formats, no longer dependent on closed, commercial applications and operating systems.

As Wan has been getting used to Ubuntu on my home PC, when she recently got her new Samsung NC10 netbook I immediately installed Ubuntu Desktop 9.04, overwriting the Windows XP Home install. So now its Ubuntu at multiple PCs at work, Ubuntu at home and Ubuntu on the road.

My car is about 1 year old now. Some stats:

• 18,000km traveled which is about 350km per week. I've done a few larger trips: Khon Kaen (3x, 1000km round trip), Yasothon (1200+km), Kanchanaburi (400km); as well as driving to work most days (25km round trip).
• 600 Baht per week spent on fuel (normally Gasohol 91, which is 10% ethanol and 90% benzene 91 octane). Average price of 26.5 Baht/litre. When I bought the car the prices peaked at about 37B/l, but dropped down to 15B/l at one point.
• 14.7 km per litre or 6.8 litres per 100km.
• Insurance was free for the first year, but I just paid for the second year: 16000 Baht for first-class insurance through Aioi; 1600 Baht for government taxes.
• Free service for 100,000km, however I had to pay about 3000 Baht for oil/parts for my 10,000km service.

The car is running fine. Only two complaints so far: my reverse parking sensors don't work very well - they often sound constantly (meaning I am about to hit something) whenever I reverse, even when nothing is nearby. Thats something that Toyota will fix for free when I take the car in next. The other problem is the blind spot caused by the front right frame between the front windscreen and drivers side window. I notice this mainly when turning, especially U-turns, as I need to lean forward to look at the front windscreen or look out the side window. I haven't noticed such a problem in other vehicles I've driven, but mainly its because of the many U-turns that are made in Thailand (on many roads you can't turn right - you need to do a U-turn and go back and turn left). Having good visibility in this area is important especially on large U-turns (e.g. under bridges) when you may find motorcycles on the wrong side of the road coming directly at you!

But in summary, I've been very happy with the purchase. The fuel statistics are constantly updated here.

Well, the holiday is over and its back to work. We got back to Bangkok about 11pm Wednesday night.

It was a great time, not only in Adelaide, Halls Gap, and Flinders Ranges, but also spending time with the family on the farm and around Mt Gambier. And of course, eating some of delicious food, especially Mum's home cooking (I put on 4kg!).

Plenty of photos in the Gallery.

From April 10 to 13 this year was the Easter long weekend. This is a time when many people go on a holiday, often camping or in a caravan. Wan, Brenton and I went camping the Flinders Ranges, a large set of mountain ranges in central South Australia considered the start of the Australian Outback.

On Thursday Wan and I drove from Kongorong to Adelaide (about 5 hours), picked up Brenton from his work about 3pm, organised our camping gear and supplies at his house, then drove another 2 hours north of Adelaide to Clare Valley. This is a good place to stop on the way to the Flinders (which is another 3 to 4 hours drive, not because it is one of Australia's many popular wine regions, but because our friends Rob and Meg live there and we get free camping. We set up our tent at their place, enjoyed a BBQ dinner, and got on the road again by about 11am Friday. [Rob and Meg have a nice simple setup on their 100 acres, and about a week after visiting them they had their first kid, Willow. Check out their journey).

We drove via Jamestown, Orroroo, Carrieton and Craddick to Hawker and then arrived at Wilpena Pound (the heart of the Flinders Ranges) about 3pm. There are two caravan/camping parks: Wilpena Pound and Rawnsley Station. Both are pretty good - this time we stayed at Wilpena Pound for $27 per night (unpowered site, 3 people). You can also stay in the National Park, especially in places like Brachina Gorge, which is much more peaceful bush camping.

The weather was perfect for the trip. Everyday was about 28 degrees, with the occasional cloud. At night time it was not too cold, especially with the fire. What did we do there? A lot of time was spent relaxing with a beer at the camp site. On Saturday we went on an easy 3 hour trek up to Hill's Homestead and then to a lookout with a great view of Wilpena Pound. On Sunday we drove up through Bunyeroo and Brachina gorges, and then back towards Wilpena via Stokes Lookout. There are plenty of other places to go and things to do, but this weekend we all wanted to relax a bit. So after a couple of boxes of Coopers and half a dozen bottles of red we made our way home to Adelaide on Monday (and then back to Kongorong on Tuesday).

Photos are available in the Gallery, as well as at Brenton's Facebook page.

Halls Gap is a small tourist town in the middle of the Grampians, a mountain range in western Victoria. We spent 2 nights there at the start of April, staying in the Halls Gap Caravan Park in the middle of the town.

Halls Gap is about 300km from Kongorong. There were 3 car loads that went: Peter and Allison; Brett and the family in their car; and Wan and I in Brett's Jeep with Dad's new camper trailer on the back. Its a nice setup, taking about 20 minutes to put up and includes queen mattress on the trailer, plus floor space for about two more, as well as a large annex.

The caravan park wasn't too busy, with most people staying in cabins and caravans. We had the open camping ground to ourselves. In the early morning and late afternoon there were plenty of kangaroos around the park, coming up to our camper trailer. Peter and Ally slept outside in their swags, and had kangaroos almost walk over them.

On arrival, after setting up we had a walk around the park and town then settled down to some drinks and dinner. The next day we all made the trek to the Pinnacle, a lookout above Halls Gap. Before going home on Sunday, we all drove up to Stawell (home of the famous Stawell Gift) and visited a couple of wineries in Great Western.

Halls Gap, and the Grampians in general, are a great place to visit with many opportunities for bush walks, camping and mountain climbing. Check out the Photo Gallery for more pics.

The Red Ochre restaurant in Adelaide serves modern and native Australian food to a very high standard. I've been there several occasions, including dad's 60th birthday party and most recently to celebrate Wan's 30th birthday.

The restaurant is located on the northern side of the Torrens river, with a great view of North Terrace including the Convention Centre, Casino and high rise buildings. There is not much immediately surrounding it (golf course, park lands) so it is best to get a taxi there. A taxi will cost about $10 to $15 from most places in the city. Note that the Red Ochre restaurant is upstairs - there is a cafe/cheaper restaurant downstairs operated by the same people.

The main attraction of the Red Ochre for many is the unique food: it serves Modern Australian food made with many native Australian ingredients, especially herbs, spices, fruit and vegetables, combined with Australian meat and game: beef, lamb, kangaroo, emu, crocodile, pigeon and more. On all occasions I've been there, the food has been delicious. This time, with both of us being small eaters, we ordered some bread for starters and then went straight to the mains. I had the kangaroo fillet and tail, while Wan choose the duck with riberry sauce. As with most Australian restaurants and pubs, the servings were quite large and we were both full and satisfied at the end. We didn't order extra salad or vegetables (knowing that the mains would be big enough) but in hindsight we should have just to mix things up.

Being a Thursday night in Adelaide, the restaurant was not full but there were still quite a few people in there. We had a corner table by the window overlooking the city lights. The atmosphere is hard to beat.

You can find a couple of photos of our food, as well as other food we ate in Australia, in the Photo Gallery.

Such good food and service is of course not cheap. It set us back $160, however that included two bottles of wine: a big Cab Sav and a refreshing Moscato after dinner. For a special occasion, it was worth it.

Wan and I stayed at the Country Comfort Adelaide motel at 208 South Terrace when we arrived in Adelaide. This was one of the cheapest motels I found on the Internet within Adelaide CBD and Mum and Dad had said it was ok in the past. Before flying out home we spent another two nights here. Although there is nothing special about the rooms and service, we found it a great spot for what we wanted to do in Adelaide.

First, don't get confused with the many Country Comforts around Adelaide and suburbs. This is the Country Comfort on South Terrace. It is owned and operated by the same people running the adjacent Grand Chifley Hotel and the Chifley on South Terrace. That is, there are three different places all next to each other: two hotels and a motel. You actually check-in at the reception of Grand Chifley and can make use of their facilities. We had breakfast included for one night and that was at the Grand Chifley.

On our first stay the room was $100 per night, and the second stay just $80 per night (booked on wotif.com). This is without breakfast. I booked a room with a double and single bed, since there was a possibility a Brenton would stay one night with us (it turned out he stayed 3 nights. There is supposed to be a $30 charge for the extra person, but we didn't say anything about him staying and no-one asked so that was free).

The room was normal size with a table and two chairs, space for suitcases, wardrobe, TV, mini-fridge, iron and standard bathroom (including shower in the bath). It was an old room, but everything worked and was clean. The rooms were on the eastern wing, numbers 1, 2 and 17. Mum and Dad had a room with queen bed one night (on the western wing, number 37?) - this room looked a bit newer with a renovated bathroom (shower, but no bath).

Although not in the heart of the city (around North Terrace), the location was convenient for us. It is only a 5 minute walk to King William Street where you can catch a free tram through the city. Or you can walk for another 10 minutes to get to Victoria Square and Central Market (and another 10 minutes to the shopping and entertainment area - it is only 2km from one side of the city to the other!). There are a few pubs within walking distance (Brecknock, Kings Head, Gilbert Hotel), a small grocer/convenience store on Gilbert Street and a few nearby cafes for breakfast or lunch. Of course it is a motel so there are plenty of car parks. A bonus of the location is that Brenton works on the corner of South Terrace and King William - a 5 minute walk away. We caught up with him on several occasions after work, usually starting with a pint of Guinness or Pale Ale at the Brecknock.

If you are looking for somewhere cheap to stay so you can explore Adelaide, and don't require special service or fancy rooms, then I recommend staying here.