Thursday, February 21, 2008

Video streaming and ISP traffic shaping



The above chart shows the data transfer usage for my broadband connection over the past month. The noteworthy change from the same usage chart for November? Over 2GB of peak-time streaming. The culprit? BBC iPlayer. Why significant? Because my ISP (PlusNet) uses traffic shaping to discourage/penalise peak-time usage, which I've been doing a whole lot of ever since my colleagues in BBC Future Media & Technology added a streaming component to the iPlayer in December. As a result, my "up to 8Mb" connection has been throttled to a painfully slow 125.87 Kbps (according to thinkbroadband's Speed Test) during peak hours, rendering web browsing tortuous and streamed video unwatchable (which is how it will remain until the end of this month's billing period).

PlusNet has a helpful page explaining traffic prioritisation (presumably so-called because it sounds slightly less sinister than traffic shaping), which contains the obligatory layman's metaphor:

"Think of it this way, the broadband network is like a motorway. When the traffic is light, all vehicles can move at the national speed-limit. Some lanes of the motorway have been reserved for important traffic, such as buses or emergency vehicles. During rush hour, most vehicles are forced to slow down. However, the traffic on the reserved lanes can continue to travel at their full speed."

The interesting word here is 'important' - an inherently subjective term (surely streaming video is important to me if that's what I happen to be doing? I don't want to be stuck in a bandwidth traffic jam if I'm trying to watch BBC THREE live or catch-up on the Six Nations). What ISPs are really interested in, unsurprisingly, is limiting bandwidth-intensive activities such as video streaming and P2P downloading which eat into their profit margins.

Until relatively recently, ISPs had a handy justification for traffic shaping: that the vast majority of video streaming and P2P downloading was illegal. This is becoming less true as more and more legitimate streaming and download offerings emerge (the BBC may have taken most of the heat on the bandwidth implications of iPlayer, but ITV, Channel 4, Five and Sky all offer similar services). Add new entrants Joost, Zattoo, Vuze, Babelgum, Jalipo, Veoh, Brightcove and Democracy (all reviewed here) into the mix and you're looking at a burgeoning market for legal downloads and streams.

So, what's an online telly addict to do? One option would be to change ISPs, although as David Meyer points out in a comment on ZDNet, "Any ISP which says it doesn't use traffic shaping at all is lying, unless it simply doesn't have enough subscribers to fill up its pipes". Part of the problem is that in the race to offer cheaper and cheaper (and in some cases free) broadband, profit margins have been squeezed to the point where a high-bandwidth user is no longer an economically viable customer. Unfortunately, that category of high-bandwidth users looks sets to grow exponentially as streaming and P2P downloading become increasingly mainstream.

One possible scenario, suggested in a typically polemical piece on The Register, is a return to metered pricing. Whilst this may feel slightly counter-intuitive, it is consistent with the idea of broadband as utility. I'm happy to pay for my water, gas and electricity on the basis of how much I use - why not my broadband? Personally, I think this is pretty unlikely. Most people were so delighted to see the back of metered dial-up access that it feels implausible that they'd accept a return to a pay-as-you-go model. A more likely scenario is that slightly more expensive, higher-bandwidth packages will increase in popularity for heavy users who (like me) would happily pay a bit more not to have their streams endlessly buffer.

My short-term solution is to return to off-peak downloading using Azureus, with its handy Speed Scheduler plug-in ensuring that it only downloads between the hours of midnight and 4pm (hence no purple in the Peer-to-peer bar). Not my preferred solution, not least because it requires me to decide in advance what I want to watch rather than sampling on a whim (which I've been doing a lot more of since iPlayer introduced streaming). I'm now back to thinking 'do I want to watch this programme enough to download a 600MB file?' to which the answer's often no.

Longer term I think I could well be shopping around for a package with a more generous bandwidth allocation and/or less severe traffic shaping. Any recommendations welcome.

Disclaimer: I work for the BBC. The opinions expressed on this blog are my own and do not represent the views of my employer.


Related fabric of folly posts:
Broadband as utility
Interesting times for the BBC online
Round-up of Internet TV services

5 comments:

Kelly D said...

Nice blog post. You might be interested in have a read of this post, which describes the effect iPlayer is having on our network in a bit more detail.
Also, if you are having second thoughts about the suitability of our products for your usage habits, you should hop onto our community site forums see if there is something which will suit you more.

Chris Parr said...

Hi there,

Hope you don't mind me posting on your blog, I thought I'd see if I could offer some advice.

First things first, looking at the screenshot at the top of the blog you are on one of our old packages, Broadband Plus. This was never really intended for heavy usage as outlined on the page I've linked.

I'd certainly suggest having a look at our current product range at the PlusNet portal as you might find one that suits you better.

We've tried to be as honest as humanly possible about what speeds to expect on these products at varying times of the day so you can judge which one is right for you.

One of my colleagues, Dave Tomlinson, has written some blogs on the BBC iPlayer and it's effect on bandwidth consumption here. He's also provided a very detailed account of how ISPs that use IPStream are charged for the service and why traffic prioritisation is needed.

One of your paragraphs touches on the PAYG model of broadband, as you use more usage you pay per GB. All of our current residential products offer this.

Hopefully I've helped to answer some questions and address some of the points in your post but feel free to contact me at cparr@plus.net if you have any queries.

Anonymous said...

According to your screenshot your on broadband plus package, you could swich over with them to broadband your way option 2 for the same cost (thier new version of what you've got atm) and get at least double the download before getting slowed down limit your seeing at the moment. Plus you can do like a pay as you go element on those accounts as well to give you more usage you just pay for on an adhoc basis.

Chris Parr said...

Looks like I broke the link to the Broadband Plus page in my previous comment. Here is the real one:-

Broadband Plus

Dan Taylor said...

Thanks for the responses guys - have just upgraded to Broadband Your Way Option 3 with PAYG extra usage. Not sure my extra £5 a month will help with your streaming bill mind!