BT told me that there is a 10 day training period for Infinity. Thats what I meant by settling in.
I had phoned them about my speed dropping a few days after installation from 37Mbs (BT speed tester) to very low levels indeed - even had it as low as 4Mbs which is just about the same as the ADSL line I had previously. Profile confirmed as still being at 38Mb. Weird thing the upload speed has hardly moved from the original 8Mbs.
Wandering off topic a bit here, but.....................
BT's own document (SIN 498) has this to say about DLM & the training period:-
2.2.5 Dynamic Line Management
Dynamic Line Management (DLM) is employed in GEA-FTTC. DLM constantly manages lines to maintain a target stability.
It does this for as long as the product exists.
At provision, the line is put on wide open profiles, allowing downstream line speeds of up to 40Mbit/s, and upstream line speeds of up to 2Mbit/s or 10Mbit/s depending on the upstream product option selected.
On the first day of operation, DLM will intervene if severe instability is detected.
Otherwise, DLM will wait until the day after provision before intervening, provided that the line has been trained up for at least 15 minutes during the preceding day.
If DLM intervenes it will set a capped profile with a maximum rate and a minimum rate, where the minimum rate is set at approximately half of the maximum rate.
The purpose of the minimum rate is to ensure that the line does not train at a rate which is significantly below the level the line should be able to achieve. If this happened, then the line is likely to remain at a very low rate till a re-train is forced by the user powering off the Active NTE.
I & some other FTTC users have noticed that the HG612 modem has a habit of re-syncing "on the fly".
These "on the fly" re-syncs are far too quick to be detected by most ISPs & thus the current PPP session & dynamically allocated IP addresses are maintained.
As IP BT's Profiles are only recalculated whenever a new PPP session is started, it is very feasible (& my connection has proven it countless times) that the modem could quickly sync at a very low or high speed, yet the IP Profile does not change.
This appears to confuse ISP & even BT customer service agents, who then start to talk about ficticious 10 day training periods.
One way to recalculate IP Profiles is to disconnect/reconnect the HG612 modem & force a new PPP session.
This can be quite drastic as DLM may see this as instability & set a lower sync speed in order to provide stability.
A less drastic way is to disconnect/reconnect the router/hub to force a new PPP session & thus recalculate the real IP Profile. As the modem stays in sync, DLM will not take any action.
Now, a 40Mb sync speed (39999k) should provide an IP Profile of 96.79% for FTTC connections (38716k), probably now reported by the updated BT speed tester as 38.72Mb, or some very close value.
Actual throughput speed can vary drastically for many reasons, such as contention at peak periods, the modem having resynced "on the fly" at a very low speed due to massive error counts, ending up with a "stuck" IP Profile etc. etc.
At a quiet time (no contention) throughput speeds as reported by speedtest.net are usually around 96% to 97% of the IP profile for FTTC connections.
As an example, my router reconnected a few days ago (reason unlnown), resulting in an IP Profile of a bit ovwr 14Mb.
Throughput was only 14Mb, but I could see the modem was still synced at the 23.67Mb oit had been at for a few days.
I reset the router & the IP Profile immediately returned to 22.91Mb (96.79% of sync speed), giving throughput of just over 22Mb.
I chose not to force a full modem resync as I have an engineer's visit booked for tomorrow & wanted to demonstrate that my connection is under-performing when he arrives.
