For years and years I've always had the Interleave Depth of my ADSL connection set at Level 8 (downstream). This has assisted with error correction and has helped a little with achievable line speed on my otherwise slow and noisy connection. This has been at the expense of some increased latency. But just recently I noticed from my router's stats that (apparently) the downstream ID was only 1. This is paramount to interleaving being off and instead the line running in Fast Mode. This seemed daft, and I wondered why this should be so.
I therefore contacted my ISP and asked for the ID to be changed to 8. They subsequently informed that this had duly been done. But now when I look at the stats, they're showing an ID of 64. I've queried this with the ISP but they insist that their engineers set it to 16 (which isn't what I asked for anyway).
Putting aside for the moment the possibility that the router could be wrongly reporting the values, is there a specific method that the ISP should use when making this change, eg. is it essential that they completely reset the user's profile before applying a new ID value? Do the downstream and upstream ID levels work independently of each other?
My understanding is that these are the options:
Downstream depth: 1 (off), 4, 8, 16, 32, 64.
Upstream depth: 1, 2, 4, 8.