[AusNOG] ADSL2+ line sync data

[John Edwards]

Hi Jeremy,

On 14/09/2013, at 1:27 PM, Jeremy Visser wrote:

> On the other hand, I've had customers who have moved from ADSL1 syncing at a full 1536 Kbit/s downstream to ADSL2+ which managed less than 1000 Kbit/s on their long lines.
> 
> Based on that, I would guess there are instances where VDSL2 in turn
> performs worse than ADSL2+.


This is probably more to do with DSLAM settings and profile tuning rather than a specific ADSL2 fault.

VDSL2 will bring with it a default of Packet-Transfer-Mode rather than ATM as the framing method. This alone is going to bring a 10% speed boost. A few more percentage points can be picked up by using IPoE rather than PPPoE at the higher layer.

If Vectoring is used, there's a fair chance that those with long lines will get better access to reliable low-frequency carriers while their neighbours with better propinquity utilise higher frequencies.

On 13/09/2013 09:33, Paul Brooks wrote:
> At worst it should fall back to ADSL2+ mode.

This assumes that the solution can get the PTM/ATM fallback working right for older modems.

Also note that vectoring is going to negate the ability to "fall back" because everyone will need vectoring-compatible CPE.

John