Hi everyone!
Cabinet: eci
Modem: vmg1312-b10a
Router: Q hub in wanoe mode
Sorry this is a long one, I’m after some advice / thoughts on this as it’s confusing me greatly vs past experiences with fttc and dlm... I can post the stats later on but just away from home right now.
So I spent 16months on PN without dlm intervention. The line went from 74mbps, to 71mbps at Christmas, 66mbps in March and finally 59mbps in April. I had several openreach engineers out and they changed pairs, changed master socket etc... eventually they managed to get it above handback threshold at 64mbps. Throughout these speed drops, it was not due to dlm in any way; the testing on the line showed minimal interfence and no crosstalk (affecting service). OR didn’t really know why it would have dropped.
Fast forward a bit and more issues with PN resulted in my leaving my contract and switching back to sky (as I had no issues before on Fibre Pro). Day of activation, my modem reported 60.8mbps connection but dlm was active (immediately) and my max attainable was 72mbps. I was under the impression there is no training period on fttc, it should be fastest out the gate and drops if necessary (based on every changeover before - unless something changed recently).
Engineer came out as it was below handback threshold, changed the pair again, speed dropped but he said he expected line to recover. Max attainable at that point showed as 69mbps on my modem. Next day, speed dropped to 50mbps and dlm had increased the depth and interleaving; and applied dlm to upstream for first time ever on my line. Called sky back up and they sent out a repeat job to OR.
The next engineer came, said it could be a lazy port so changed my fibre port on cabinet. On resync my modem again was connected at 51mbps but attainable was 74mbps. I asked him to do a dlm reset and he said won’t make a difference...
The OR kit device they use to test the line showed it as 51mbps connection, 51mbps max attainable (like dlm wasn’t active). He did the reset on my request and it jumped to 68mbps (with no dlm) and the engineer was a tad surprised.
Last night, at 1am my line resyncd and again dlm was active, interleaving 8 inp 3, d:1217 or something. Connection now shows as 62mbps with an attainable of 74mbps again. 1 LOS, 8 LOF and < 600 ES errors yesterday; so not enough to trigger dlm intervention afaik? No reboots on the kit etc at all and was online for the full 96bins...
My SNR now with dlm on the line is 6.3db, same as it is when dlm is not active; so my downstream snr has not increased as I expect it to with dlm active?? This happened on the activation day too, but according to everyone remotely my line is at max speed and they don’t see the dlm intervention on the line; yet locally it tells me 74mbps attainable (and on dlm reset, it was 68mbps).
Anyone experienced anything like this before (snr not increasing with dlm active, etc.)?
In the past, most de-dlm resyncs happened at 4am-5am and activate dlm resyncs happened at 11am-12am; so 1am resync is strange for me too... Sky are also unable to read the line speed from my router and have to use a different system to get it; not sure if that’s related to using the modem in the mix or not; but I don’t want to disconnect it to test it with dlm active as I want to keep an eye on what’s happening.
Also, my line always used to sync higher with the PN HH5a (lantiq to eci cab). Since the switch the Broadcom based units sync faster than lantiq (tested using an old eci modem). Something just don’t feel right here 🤯