Filtering technically impossible for us, says NBN Co

Renai LeMay
Wednesday, 06 July 2011 10:20

IT Policy - Regulation

Along with Telstra, Optus has pledged to implement a voluntary filtering framework developed by the ISP industry's peak representative body, the Internet Industry Association. The filter, which is being seen as a more moderate industry approach developed in reaction to the Federal Government's much more comprehensive filter scheme, will see the ISPs block a 'worst of the worst' list of child pornography sites generated by international police agency Interpol.

However, a NBN Co spokesperson said late yesterday that its network wasn't compatible with the filter as the filtering took place at a different network layer. 'NBN Co is building a layer 2 open access network moving bits of data from a premises to a Point of Interconnect,' the spokesperson said. 'Any internet filtering would need to be implemented at Layer 3.'

Layer 3 is otherwise known as the network layer under the widely used seven-layer model of computer networking, and is responsible for routing delivery of network packets. The filtering scheme being promulgated by the IIA sees the ISPs add a blacklist of banned addresses into ISPs' DNS servers.

In comparison, NBN Co is building its own network on layer 2 of the seven layers, otherwise known as the link layer. This layer oversees the transfer of data between adjacent network nodes. An example of a data link layer might be the Ethernet or PPP network standards.

The move will allay fears that NBN Co could impose the voluntary filter on customers of its wholesale service. The government-owned telco does not aim to provide retail services to customers, but rather will only sell its services to other telcos, who will then provide services to end users. Eventually every major telco and ISP in Australia are expected to be using NBN Co's network in some way.

The news comes as a substantial split has emerged in the ranks of Australia's ISPs regarding the IIA's scheme. Telstra and Optus, which between them boast the majority of Australia's broadband customers, are supporting the IIA's framework, and Telstra's implementation of the filter has already gone live.

However, others such as Internode, iiNet and TPG, are not implementing the filter for now, preferring instead to see how the issue plays out from a law enforcement point of view. With telcos such as Optus admitting that the filter can be defeated with trivial changes to users' DNS settings on their PCs, Internode and digital rights group Electronic Frontiers Australia have labelled the IIA's initiative as 'security theatre' '” an initiative which won't actually increase security, just the appearance of it.

Image credit: Mike Gieson, royalty free