Kitz Forum
Broadband Related => Broadband Hardware => Topic started by: digitalnemesis on September 04, 2020, 12:52:50 AM
-
https://forum.kitz.co.uk/index.php/topic,24720.30.html
https://forum.kitz.co.uk/index.php/topic,24720.msg416583.html#msg416583
Its been a god send, as it allowed me to set 3dB SNRm on my Zen ECI line.
https://forum.kitz.co.uk/index.php/topic,17181.msg409324.html#msg409324
Since my lines have been getting slower and someone let slip that you can mess with the downstream SNR on this hardware, I decided to give it a try with latest OpenWRT and -3dB SNR downstream.My Zen line changed from 66.14Mbit to 73.99Mbit, a 7.85Mbit increase:
@Alex Atkin UK
Is it true that the Home Hub 5a on OpenWRT can set a 3dB SNRm on VDSL2 connected to an ECI cab???
-
Yes, hh5a with Openwrt, also old BT eci modem with lantiq chipset and Openwrt , and several Draytek models which also got lantiq chipset. With these modems you can set snr lower than standard 6db on eci cabinet.
-
Lantiq chipsets with full access to the commands line can set any downstream SNRM target they like on both ECI and Huawei cabinets.
There's about 1001 threads on the forums on this.
-
Yes, hh5a with Openwrt, also old BT eci modem with lantiq chipset and Openwrt , and several Draytek models which also got lantiq chipset. With these modems you can set snr lower than standard 6db on eci cabinet.
The ECI firmware however is using an old version of OpenWRT so doesn't seem to have the SNR in the UI (Luci) whereas the HH5a does.
-
Lantiq chipsets with full access to the commands line can set any downstream SNRM target they like on both ECI and Huawei cabinets.
But don't think this is a magic bullet. My line ran for months on 3.6dB SNRm but then got banded. The banding went away for a few months but then came back again and doesn't seem to be going anywhere this time. :'(
-
Lantiq chipsets with full access to the commands line can set any downstream SNRM target they like on both ECI and Huawei cabinets.
There's about 1001 threads on the forums on this.
first i heard of it, problem for me though is they sync notably lower so 3db on lantiq would be comparable to 4-5db on broadcom maybe.
plus the low snrm would inevitably get me interleaved on this new dlm and fec overhead would wipe it all out with a latency penalty to top it off.
-
first i heard of it, problem for me though is they sync notably lower so 3db on lantiq would be comparable to 4-5db on broadcom maybe.
plus the low snrm would inevitably get me interleaved on this new dlm and fec overhead would wipe it all out with a latency penalty to top it off.
Its definitely only useful on a fairly clean line. Its never triggered interleaving on my good line, but it did on my bad one and wasn't stable at all with G.INP. I can't understand why its triggered banding on my good line, but I guess that's better than interleaving.
-
Alex I think my line would work fine day to day, but ultimately it would be more vulnerable to a tiny burst of noise crippling it on the DLM. I think my line ran at not far off 4db for a while last year, the uptime ended with me flashing a new firmware on my modem.
Thinking about it some more though, a 3db target I would be syncing around 5db because I dont need much more to hit max sync.
-
I have it set to -3.5dB target and the estimated max claims 79.830Mbit.
Sounds about right as before my banding changed it was around 76Mbit at 3.4dBm (it was still banded funnily enough).
I miss the days when DLM did not exist and you could just push the line insanely hard. I remember when DSL Max launched, it was such a huge downgrade as I used to also run 3dB down on ADSL2+ on Be Broadband. I was always impressed how a 2kM line could be so stable, but I guess far fewer people cared about the Internet back then.
FTTP can't come fast enough, I'll be glad to be done with this yoyoing.
-
Yep DLM is the one single reason my line isnt pushed as hard as it can go.
-
I take it even with this snr tweak it won't work if your line is banded by DLM?
-
correct, the cap will ultimately overcome a lower snr target that would exceed the cap.
The same as how lines cannot exceed the product cap.
-
I take it even with this snr tweak it won't work if your line is banded by DLM?
It will technically "work" in the sense that it will indeed change the "target" SNRM.
The max attainable rate will increase in line with the target chosen.
It won't work how you would like and the banding will still cap the sync and therefore the "current" SNRM will remain high.
The same as how lines cannot exceed the product cap.
^^^Exactly as Chrysalis says.
Both are applied by setting the upper end of the current DLM profile.
If you work out how to bypass banding then you could in theory exceed your products cap (the sync at least).