The UK regulatory authority for electronic communications, OFCOM, has launched aninvestigation into the traffic management practices of two Internet service providers -Vodafone and Three -to determine whether they are compliant with the EU Open Internet Access regulation. Among others, OFCOM will look into Three's 'traffic management practices such as  "throttling" or intentionally slowing down particular categories of traffic (e.g. video traffic, Peer-to-Peer and Virtual Private Network traffic), including where traffic management is applied when customers are roaming. In the case of Vodafone, the regulator will examine 'traffic management practices relating to "Vodafone Passes" -e.g. throttling particular categories of traffic -including where traffic management is applied when customers are roaming',  and 'the transparency of exceptions to zero rating within the