While legacy services such as ADSL2+ exist on the Telstra copper network, speeds will be limited to reduce interference.

Despite what the documentations says, nbn™ has now denied (on the record) that they will “limit” speeds to 12/1. Please refer to this post here for more information.

In the most recent draft of the Wholesale Broadband Agreement (WBA 2.2) released Access Seekers for FTTN Business Readiness Testing, nbn has revealed that speeds will be limited to 12/1 Mbps during the so-called “Co-existence Period” on the Fibre to the Node network.

During this period, all bandwidth profiles will be restricted to reduce interference with existing legacy services that run on the Telstra network. A similar limitation will apply to Fibre to the Basement, however, the maximum speed will be limited to 25/5 Mbps rather than 12/1 Mbps.

In the document, the company said that the speeds will continue to be limited until “NBN Co is satisfied that Downstream Power Back-off is no longer required”:

11.5 Co-existence Period

NBN Co will disable Downstream Power Back-off in respect of an NBN Co Node when NBN Co is satisfied that Downstream Power Back-off is no longer required in respect of that part of the NBN Co FTTB Network or NBN Co FTTN Network (as the case may be). The Co-existence Period for Ordered Products supplied by means of that NBN Co Node will cease at such time. FTTN BRT Special Terms – WBA 2.2 Draft – NEBS Product Description

Despite explicit wording of the documentation, however, a spokesperson for nbn™ has denied to technology publication ZDNet that they will limit speeds. Instead, they have indicated that they will guarantee speeds of at least 12/1 mbps.

During the period when NBN is upgrading a suburb with ADSL to VDSL2 speeds will not be limited to 12/1Mbps. During this so-called ‘co-existence period’ line speeds on the NBN FttN service will still be substantially faster than those being delivered via ADSL2+ from the exchange Josh Taylor, ZDNet: NBN will only guarantee 12Mbps speeds during FttN transition

For customers who live close to the exchange, the speed attainable over the Fibre to the Node network may actually be lower during the “Co-existence period” than what’s possible over their existing ADSL2+ service. The typical theoretical maximum speed for ADSL2+ is 24/1 Mbps and is delivered from the Telstra exchange.

However, since the duration of the Co-existence period varies depending in the area still using ADSL or special services – customers who experience greater speeds over ADSL2+ (greater than the 12/1 Mbps offered) would still need to migrate to NBN before NBN Co can declare the “Co-existence period” over.

Once the Co-existence Period is over, nbn™ will provide 12/1 Mbps and 25/5 Mbps speed profiles similar to those on Fibre to the Premises with higher speeds only available as an “up-to” range. However, NBN Co also states in the document that it is considered acceptable if the customer only receives speeds set out in the PIR or PIR range “once” in 24 hours.

FTTN BRT Special Terms – WBA 2.2 Draft – NEBS Product Description (PDF)