In its regulatory submission this week, Telstra says the new national fibre-to-the-node (FTTN) roll-out should not have to interface with current network technologies such as the copper ADSL2+ network, because of impacts on performance.
"The government should not force the network operator to accommodate old and new technologies, which are not compatible," Telstra said.
According to a spokesperson for the telco, having the existing DSLAM network running in parallel "compromises the actual performance of the new technology" since the node power would have to be reduced.
"The whole point of going to the new system is that it's fully integrated," the spokesperson added.
Optus sees Telstra's stance as competition choking: "This is a continuation of them wanting to strand existing competition in DSLAMs," Maha Krishnapillai, Optus director of government and corporate affairs said.
Internode MD Simon Hackett sees no reason why the older network should not run in parallel: "The 'old' (competitive ADSL2+ services) and the 'new' (node-based VDSL2) are in fact technically compatible. They can coexist with appropriate software configuration settings in the new VDSL2 equipment," he told ZDNet.com.au.
In a presentation in April, Hackett said that it is technically possible for the two networks to coexist using commercial-off-the-shelf hardware, and that the know-how is also at hand to connect lines from ADSL2+ to VDSL2 and back again via software remote control — requiring no labour.
"To claim they are not compatible is a Telstra excuse that tries to avoid admitting that their real agenda for the NBN is re-monopolisation of the access network and driving up access pricing to bolster their profits," Hackett said.
Retaining the older services is necessary for competition, he added, and "It avoids throwing the bay out with the bathwater."
It's currently technically possible for the two networks to exist, according to Paul Brooks, MD for Layer10 advisory, and member of the Communications Alliance VDSL working group, however, some performance constraints remain.
"Coexistence is possible; the thing is whether the industry or providers or customers are willing to accede the performance decrease," he said, adding that having both networks can reduce VDSL speeds around 10 to 20 per cent.
However, technical issues shouldn't decide the issue according to Brooks. "The technical aspects can work either way — the choices more often come down to higher level social issues."