An Optimised Network Packet Filter (my CompSci final year project)

Ian Leader: Something of a blast from the past: as part of my recent job change, I had to dig out and scan the write up of final year BA Computer Science project, ‘An Optimised Network Packet Filter’ (click to view or download PDF) that I presented at Cambridge University in 1994.

Network packet filters were ‘in’ around this time, as part of the then trend towards microkernel operating systems. The idea was that you move as much as possible out of the kernel into user process/memory space, so that it was easier to modify. The network packet filter would identify and extract the content from all network packets and dispatch them to the appropriate user process.

However, two factors subsequently turned the tide and networking code back into the kernel:

  1. the growth of the Internet and the corresponding importance of high performance networking
  2. the lack of any real need to modify packet handling on a regular or ad-hoc basis outside of academic environments (everyone uses some form of Ethernet and UDP/TCP pretty much all the time, and not much else)

The project focused on optimizing the process of identifying and decoding packets – basically building a list of patterns to match for an applying them efficiently against incoming packets. In theory, the algorithms I applied worked pretty well compared to existing approaches, but I was never able to do any real world testing. This was partly due to time constraints on the project, but also due to the security culture in the computer lab at the time, which basically amounted to:

  • Never let a (undergraduate) student have root
  • Don’t let a student see any of the UNIX (DEC Ultrix in our case) source code related to security or the kernel
  • Don’t let a students access the network with their own device

So I wasn’t even allowed to do my own promiscuous network sniffing to get real data to test against – my supervisor had to do it! Universities might still be like this except for Linux!

The project was supervised by Derek McAuley who was a great teacher and mentor. The original, complete with typos (the OCR ate them when I scanned it) and my grade (can you guess?) can be found in the library of the computer lab at Cambridge.

What Gmail and the iPad have in common (and most LMS’s don’t!)

Ian Leader: Paul Buchheit, probably best known as the creator and lead developer of Google’s Gmail, recently blogged that “If your product is great, it doesn’t need to be good“. His point is that really great products will start out by focusing on a small number of really important features, and not try to tick every box in the competition’s feature list. This approach lets you focus on what’s really important to start with, and then to evolve the product with the really important ‘missing’ features.

Sound good? I recently wrote  about my experience on how this applies to the world of commercial Learning Management Systems for LINE’s HeadLINE newsletter. You can read the full article here: http://www.line.co.uk/viewpoints/what-gmail-and-the-ipad-have-in-common-and-most-lmss-dont.

I pay the telco, so why should Google?

Ian Leader: Catching up after a long weekend in the wilderness, and the Telcos are bleating about all that terrible data they have to carry so that I can watch YouTube and friends.

In an article in the FT, the former state telcos in France, Spain and Germany are all making comments along the following lines: “Google should share some of its online advertising revenue with the telecoms groups, so as to compensate the network operators for carrying the technology company’s bandwidth-hungry content” (César Alierta, chairman of Telefónica).

Sorry, but I don’t buy it. I pay CableCom (Swiss cable company) the equivalent of about 90 USD / month for their fastest domestic broadband connection (25/2.5 MBit/s), and I pay SwissCom (former Swiss state telco) every month for a data allowance. If this isn’t enough to pay for the required infrastructure, then they should charge me more or provide less bandwidth for the same money. I can either pay up or switch to another provider.

And there’s the rub – the telcos might want to be more than “dumb pipes” but that’s essentially what they are, and it’s not in the interests of consumers for them to be more than that. If my web services are tied to my internet connection, then I can’t switch easily, nor can I choose to get my mobile and fixed line internet from different providers. Think about that .com email address you had when you first got on the internet. You give yourself far more flexibility if you go with Yahoo/Gmail/Hotmail etc.

So the telcos have become dumb pipes because that’s what a fairly efficient market supported by government regulation has delivered over the last ten years. And they take money from their consumers, so there’s no automatic moral case for them to take money from providers – nor do they have the leverage to force this to happen (unless they decide to act as a cartel!)

Good for you and me, and a shame they can’t move on from complaining about this and work on being the best plumbers they possible can be.

Mobile Barcoder Firefox Addon – a Hi/Lo Tech Coupler for your laptop and mobile

Ian Leader: I’m playing around with QR codes a lot at the moment, and I just came across the Firefox Mobile Barcoder addon. If you mouse-over the icon in the bottom browser bar, this addon will create and display a 2 dimensional QR code containing the URL of the current web page. Then just scan it with your SmartPhone, and the URL will open in your mobile – a handy way to avoid typing on your phone:

Unfortunately I couldn’t get it to work with any software on my BlackBerry Curve (8520), but it works perfectly with the barcode reader on the T-Mobile G1 (Android):

Continue reading ‘Mobile Barcoder Firefox Addon – a Hi/Lo Tech Coupler for your laptop and mobile’

Adding DNS entries to a Fonera 2.0n or what’s FON really about?

Ian Leader: I’ve been using a LinkSys (now Cisco) WRT54GL as my home WiFi / router / firewall for about four years, and particularly since the OpenWrt initiative released the WhiteRussian version of their open source firmware, it’s been a joy to use: a fully-featured, flexible web GUI with both simple and advanced administration modes, access to a very wide range of linux packages, and a plugin architecture in the web GUI that allows you to add and configure a great deal of them without getting your hands dirty.

However, the hardware’s old and doesn’t support 802.11N wifi, so I bought a Fonera 2.0n. As well as 802.11N, it’s got a host of other features like USB support (for storage or webcams, or…) and applications to handle uploads and downloads to Picasa, FaceBook, Torrents and other applications / protocols. It’s also based on OpenWrt, and uses a version of the same Luci user interface.

Unfortunately, for my setup there was one key difference: There’s a module called dnsmasq on both platforms that runs a DNS server (amongst other things), and allows you to specify DNS entries for local servers. In OpenWrt WhiteRusian this is pretty simple: You add entries to /etc/hosts.local in the normal format e.g.

192.168.1.100 server1

Then reboot the device (this is pretty brute force, but simpler than remembering which init.d / rc.d script to run). Other settings like the DNS suffix (e.g. myhouse.mydomain.com) can be set in the web UI.

The Fonera doesn’t play nicely like this, and there simply doesn’t seem to be any file pre-configured where you can add entries, nor does it let you set the DNS suffix through the web UI. Here’s how I made it work:

Continue reading ‘Adding DNS entries to a Fonera 2.0n or what’s FON really about?’

Bringing together e-Learning, Communications and Knowledge Management

Ian Leader: Inside Learning Technologies magazine’s November 2009 issue published an article I co-authored with colleagues Piers Lea and Patrick Dunn, “The Unification of e-Learning, Communications and Knowledge Management“.

The article looks at the benefits of bringing these complementary areas together within organisations – a trend that is definitely underway. It also considers organisational structures and other issues that have impeded widespread implementation of technology platforms that bring knowledge, learning and communications together within corporations.

Read the full article here.

RoadSync release decent push gmail client for Nokia / Symbian – better than BlackBerrry?

Ian Leader: About a year ago,  I posted a new years wish list that included “A decent Google mail…client for the Nokia E-series phones.” At the time I was using RoadSync to get push email from Exchange on my E51, and wondered if they might add IMAP support.

They left it almost to the last minute, but yesterday, Roadsync 5.0 for Symbian S60 was released, an now includes support for Google apps: push IMAP email, in addition to calendar and contacts sync through ActiveSync that’s been available since the summer.

I’m pleased to say that it does exactly what it says on the tin:

Continue reading ‘RoadSync release decent push gmail client for Nokia / Symbian – better than BlackBerrry?’

The Difference Engine

Jon Bradford: The Jay Eye Sea blog has been (sadly?) bereft of posts from yours sincerely over the last 9 months.  The primary reason has been The Difference Engine, an early stage digital accelerator based in the North East of England.

Since inception, it has taken around 12 months and a lot of discussions to get the programme off the ground.  As with any business proposition I had to articulate my rationale and justification for the project – my attempt was a white paper called “A Perfect (Disruptive) Storm”.  For the purposes of history and for those might be interested in attempting this in their own region a copy of the final “draft” of the paper is available below.

Continue reading ‘The Difference Engine’

Nexus One: Android’s Gold Standard

Jon Bradford: It is all over the blogosphere – the fabled Google phone really does exist.  The first picture of the Nexus One has already appeared on Twitter and it is only a matter of time before we start getting full reviews by Google employees and the internet’s glitterati.

So why have Google got themselves into the hardware game after many different quotes from Eric Schmidt to the contrary?  By creating the Nexus One, I believe that Google have created their own Android “Gold Standard” against which all other Android phones will be measured.  This is in part to challenge hardware manufacturers and more importantly to control network operators.

Continue reading ‘Nexus One: Android’s Gold Standard’

Launch of Google groups brings Apps closer to a credible Intranet platform – but search still a problem…

Ian Leader: Today Google launched Groups for Google Apps, making discussion forum functionality available to organisations using the Premier and Education editions of apps. I think this is a significant development, as it finally makes Apps a credible option for company Intranets. Although Google have promoted Sites as a tools for Intranets for some time, the lack of any form of discussion forum (beyond blog comments) was a serious weakness compared to commercial and open source tools that have been generally available for some time.

Continue reading ‘Launch of Google groups brings Apps closer to a credible Intranet platform – but search still a problem…’

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