Not as I understood it on FTTC.
I can recall seeing somwhere on Plusnet forums that the Interleaving is currently always set 'on' on FTTC and not even the ISP's can switch it off.
The document linked to was great for ADSL, written in easy to understand layman's terms.
However, some areas require a complete revison for VDSL2/FTTC services, such as DLM actions, BRAS Rate updates, even the use of separate modems/routers has quite an impact.
e.g. a modem re-sync does not always initiate a new PPP session, thus the IP Profile / BRAS Rate can end up stuck at a high or low level, completely unrelated to the modem's sync speed, which really confuses a large number of users as they cannot understand why their throughput appears to have no relationship to the IP Profile as reported by the BT Tester.
More often than not, the ROUTER has to be reset to force a new PPP session that will
actually update the BRAS Rate / IP Profile.
Having "found out" quite a bit about VDSL2 & FTTC, mainly by trial & error, we could possibly write a similar document between us.
However, some elements of how FTTC works are apparently "secret" (especially any stats from the supplied locked modems) & the document would not be "official".Regarding Interleaving,
I am with Plusnet & their various reports (& my own logs) confirm that Interleaving can be in various states for DS & US Separately:-
OFF - Interleaving depth of 1
LOW - I have seen DS Interleaving depths of up to 1700 , still classed as LOW, while US was OFF
HIGH - I am not sure what depth signifies the start of HIGH.
Further, I have not seen MEDIUM as an interleaving state but it MIGHT exist, alternatively it may simply swith from LOW to HIGH.
Plusnet have officially confirmed to me that they have no control whatsoever over Interleaving settings for FTTC services as DLM handles it automatically.
Plusnet also confirmed they are unable to request a manual override of Interleaving settings via BT OR.
Currently, Interleaving is completely OFF for my connection (DS & US both at a depth of 1 - from my own logs).
Also this from Plusnet's reports:-
Test Outcome Pass
Test Outcome Code GTC_FTTC_SERVICE_0000
Description GEA service test completed and no fault found .
Main Fault Location OK
Sync Status In Sync
Downstream Speed 32.2 Mbps
Upstream Speed 5.8 Mbps
Appointment Required N
Fault Report Advised N Profile Name 20M-40M Downstream, Interleaving Off - 3.6M-7.2M Upstream, Interleaving Off
Time Stamp 2012-04-08T05:15:00
Some other documents do suggest that Interleaving adjustments CAN be requested for various profiles:-
"Standard - Auto, what we are all currently on.
Fast - Fastpath, lower ping for gamers."
An official FTTC specific Myths & Legends document from OR would be most helpful for end users.
However, as it might have to give some "secrets" away, I wouldn't hold your breath waiting for its release into the Public Domain.