Congestion Management and DPI in the UK

I’ve heard for some time now that most if not all broadband ISPs in the UK have implemented some sort of congestion management on their networks (beyond what TCP itself provides) and that in many cases these management policies are targeting specific application types. But in my search for a comprehensive resource documenting these policies, I’ve come up empty-handed. Perhaps as a result of Ofcom’s Voluntary Code of Practice for fixed line broadband ISPs, a good number of ISPs have disclosed their traffic management policies on their web sites. So it appears that collecting this information in a single location shouldn’t be too difficult, and I hope to begin that process right here.

In the selection of policies I’ve seen, the ISPs don’t specifically address whether they use DPI for congestion management purposes. However, many of them do disclose whether they target particular applications or protocols (peer-to-peer traffic is the most common target for throttling, unsurprisingly), which provides a crucial hint about DPI usage since it’s difficult to imagine how particular applications or application protocols can be singled out for management in-network without some sort of inspection of application data.

The table below is the beginning of what I hope will become a comprehensive resource documenting whether UK ISPs have disclosed their traffic management policies, and which ones appear to target particular applications (and thus may be employing DPI on their networks). I’ve started with a handful of UK ISPs and hope to keep adding as time goes on.

ISP Has congestion management policy? Apps/protocols throttled (if any) Apps/protocols prioritized or otherwise identified (if any)
BT Total Broadband Yes
  • P2P
  • video streaming above 896Kbps for BT Total Broadband Option 1 customers
O2 Yes
  • P2P (throttled to 50kbps)
  • streaming
Orange Home Yes
  • P2P (specifically mentions BitTorrent and Kazaa)
  • gaming
  • Orange’s second phone line service
PlusNet Broadband Yes A selection of the following:

  • web sites that facilitate large downloads
  • mirror sites that facilitate large downloads
  • content distribution networks (CDNs)
  • VoIP
  • gaming
  • browsing and email
  • streaming
  • VPN
  • PlusNet FTP
  • other FTP services
  • P2P
  • binary Usenet
Sky Yes
    P2P
  • streaming
  • newsgroups
TalkTalk Yes
  • P2P
Virgin Media Yes