I’ve seen so much rubbish here about the cause of the speed problems, so let me give you my opinion _as a clued up Internet user_

It’s an economic problem to do with indiscriminate consumption of a scarce resource. Now that I have scared most of you off, I’m left with the people that should understand – good.

International Bandwidth is a scarce resource, it’s finite and it’s a direct cost for the supplier. In the older days, when Xnet charged users for all bandwidth ($1/gig), they had a fair number of heavy users – but heavy users are a GOOD THING to have. They consumed a lot, and paid for it.

Unfortunately for some unknown reason, they decided that they needed to more fully utilise their international bandwidth, and try and modify customer behaviour to even out their international link utilisation so they put the Torrent plan in place.

What this did though, was put an effectively flat rate plan in place for midnight to 8am. Flat rate plans don’t encourage heavy or rational use, they encourage indiscriminate use. Indiscriminate use is bad. People can (and do) download 3 movies, watch one, delete the other two.

That in itself isn’t so bad, but the methods used for downloading today are incompatible with concurrent interactive use in a flow based fairness scenario. Or put another way, Torrent users after midnight still get decent speeds because they have 100+ connections open at once, all running at 1-3K/sec. Unfortunately because of the way that bandwidth is allocated, the interactive user gets 1 or 2 flows of 1-3K/sec.

Now, I just got off the phone from Xnet and their CSR admitted they have a major problem and said they are adding more international at the end of the month – unfortunately, there is significant research indicating this won’t help, and can in the medium term, make things worse. See Bob Briscoes paper "We Do Not Have to do Fairness Ourselves” linked here: http://www.cs.ucl.ac.uk/staff/bbriscoe/pubs.html#relax-fairness

Now, there are a couple of ways to solve this, but they are all difficult, here are some ideas that would work:

- Lose the Torrent account – I know it’s difficult to withdraw a plan, but indiscriminate users are money losers and resource hogs. You DON’T want them on your network. They overconsume your scarce resources and starve the paying users. They’re also price sensitive and I’d guarantee they make significantly less for Xnet through VFX than their other users. Simply removing the 75GB free would solve this problem overnight.

- Plan based traffic fairness. With pay per GB users and Indiscriminate Torrent users in the same Bandwidth pool, the Torrent users will ALWAYS monopolise the available bandwidth and the interactive users (in the midnight to 8am time) will be starved. Moving the Torrent users to their own bandwidth pool would isolate them from the pay per GB users and solve the problem as well – but this is not trivial and involves some investment.

- Document for your existing pay per GB users that between the hours of midnight and 8am, your network is optimised for Torrent users only and interactive use is essentially impossible.


So there you go – the current performance of the Xnet service during midnight to 8am is a completely predictable result of encouraging indiscriminate use by some users and not separating those users from the existing pay per GB users.

As I have said, this is my personal opinion only, and I would welcome and comments or corrections.

 
Regards
Neil G