[Moderator edit: This thread has been created by splitting it off from the Draytek Vigor 130 sync speed thread.]When I was writing about the DLink I should have said G.INP not just INP.
Since the OP is on ADSL2+ (correct?) the DSLAM presumably won't speak G.INP ? Or is this different because it's Sky iirc not BTx. I haven't heard of G.INP being in use with ADSL2 even though I know retransmissions are in the G.992.3 standard - if we're talking about the same thing.
I didn't know that the DLink doesn't do G.INP, and I haven't look because if I'm right, then I can't use it because BTW 21CN doesn't have it I believe, as I suggested.
When you see INP do you think this refers to the combination of
R and
M parameters in G.992.3? (Amount of FEC bits.) Higher R (and greater interleave depth) equals better reliability. Higher R means more overhead so less true throughput.
I hadn't noticed that there's no upstream G.INP with ADSL2+, I've learned something so thanks for that.
Does Sky speak SRA for ADSLx?
As for G.INP with the DLink, provided a modem wins in real-world speed tests as opposed to just getting the best sync rates, which you need to do to take account of the differing levels of overheads (PPPoEoA vs PPPoA and possibly differing R and M [or S] plus any other overheads), then it just wins and the fastest is the fastest, provided it is reliable. I myself wouldn't let the G.INP feature be the sole deciding factor, unless the line has really bad noise problems and things just won't work properly otherwise. It's an important thing to have nonetheless. It also depends on how you feel about ultimate speed vs reliability/predictability tradeoffs.