The correct WAN service for FTTC?

Just a quickie.

I use a Billion 8900AX2400 for my VDSL (FTTC) connection. The Configuration page in its user interface shows, under WAN Service, pppoe_0_1_0.101. But with my previous Billion router it showed as pppoe_0_1_1.101. Which of these is correct?

If the current pppoe service is wrong, how is it that, for the last two or three years, my VLAN connection has seemingly been working okay, with only one or two breaks in connection in that period? Just lately, however, download speed has dropped from 40M bps (capped at that speed) to just under 39M bps and notably my upstream power has gone negative (-1.1dBm), also lowering the upstream speed.

Negative power? Where do you get that idea from?

That negative power figure is not my idea, it's what's showing in my router's stats for WAN upstream power.

Despite that whacky figure, I'm able to upload packets okay, it seems.

Is that upstream power figure to be trusted, do you think? Quite a number of individual stats for upstream, on this 8900AX2400, show as what I would deem as infeasible, eg. upstream attenuation = 0. Is it perhaps a characteristic of Billion routers that they never show upstream stats that are at all correct, and that only the downstream ones should be relied upon?

Where does it say the power is negative? It may say -1.1 dBm but that is NOT negative power.

Yes, I know. Perhaps I chose my words badly. What I meant was that the stats are reporting a negative figure for upstream power. Until a few months ago that figure was +3.2dBm.

I've begun to wonder whether this is due to maybe the WAN Service being wrongly specified. But I can't recall which of the two it should be. On this Billion, it's automatically set by the firmware, so I have no control over it (other than maybe to change to an earlier firmware).

It's nothing to do with your WAN settings. You will get the same power levels with correct WAN settings, incorrect WAN settings or no WAN settings at all.

The power level is determined by the DSLAM/cabinet. The power levels are adjusted at every sync and take many things in to account.

-1.1dBm isn't negative power.
dBm is power relative to 1 milliwatt. So 0dBm is 1mw.
A negative figure simply means less than 1mw.
-1.1dBm is around 0.77milliwatts

Higher power isn't better than lower power or vice versa. It just means less power is required to reach the SNR per tone targets.

In reply to a post by meditator:

notably my upstream power has gone negative (-1.1dBm), also lowering the upstream speed.

Could easily be a software reporting error, many routers/modems have had problems with these figures, even the originally Openreach supplied HG612 had problems with its web pages.