Fritzbox 3370 limited ADSL Modem speed

Hi all
I already read up my issue and noticed that it is heavily discussed and there might not be much hope. I just like to ask for clarification if I can do anything (configuration or firmware wise) to improve my ADSL connection speed? Most of the configuration was automatic or just copied from the OpenWrt ISP configuration site.

What makes me curious is that the same device using stock firmware is giving me a higher data rate and the ATTNDR as well proposes a higher possible rate.
Any input, even if someone using the same setup confirms there is no other option, would be highly appreciated.

I am using a AVM FRITZ!Box 3370 Rev. 2 (Micron NAND) - xRX200 rev 1.1 with OpenWrt SNAPSHOT r9909-9af2735734 / LuCI Master (f138fc93) to connect to german DTAG ISP.

On the LUCI overview page are show the following statistics:
Line Mode: G.992.5 (ADSL2+)
Line Uptime: 1d 7h 48m 6s
Annex: J
Profile: -
Data Rate: 8.191 Mb/s / 2.736 Mb/s
Max. Attainable Data Rate (ATTNDR): 15.052 Mb/s / 2.732 Mb/s
Latency: 8.0 ms / 5.0 ms
Line Attenuation (LATN): 36.3 dB / 17.0 dB
Signal Attenuation (SATN): 34.7 dB / 17.5 dB
Noise Margin (SNR): 7.6 dB / 6.0 dB
Aggregate Transmit Power(ACTATP): 16.4 dB / 13.1 dB
Forward Error Correction Seconds (FECS): 14907 / 286
Errored seconds (ES): 0 / 1
Severely Errored Seconds (SES): 0 / 0
Loss of Signal Seconds (LOSS): 0 / 6
Unavailable Seconds (UAS): 52 / 52
Header Error Code Errors (HEC): 0 / 0
Non Pre-emtive CRC errors (CRC_P): 0 / 0
Pre-emtive CRC errors (CRCP_P): 0 / 0
ATU-C System Vendor ID: Infineon 130.185
Power Management Mode: L0 - Synchronized

In my /etc/config/network are the following lines to be found:

config atm-bridge 'atm'
        option vpi '1'
        option vci '32'
        option encaps 'llc'
        option payload 'bridged'
        option nameprefix 'dsl'

config dsl 'dsl'
        option xfer_mode 'atm'
        option line_mode 'adsl'
        option annex 'j'
        option tone 'bv'
        option ds_snr_offset '0'

config interface 'wan'
        option ifname 'dsl0.7'
        option proto 'pppoe'
        option ipv6 'auto'
        option keepalive '0'
        option username 'xxx'
        option password 'xxx'

Apart from that I am simply default gateway routing all the traffic from the other interfaces / zones to that NATed wan interface with the shown configuration.

Kind regards

Could you post the ADSL numbers from the original firmware and the firmware version here, please? Potentially, you could try another DSL driver blob, maybe even the exact same driver blob you use under fritzos....

In general the performance limits you refer to only apply to VDSL2 links with speeds in excess of 50 MBit/s, your VRX288 (PSB 80920) modem should not have any issues to deal with the maximum throughputs achievable with ADSL2+/ G.992.5[1]. What matters here are the negotiated link speeds between ADSL line cards (DSLAM) and your modem, taking your local line losses/ noise into account (which you may influence only slightly via snr offsets, but 6 dB SNR is considered the minimum required for a stable connection).

[1] What is your contractually agreed upon line speed?

Thanks for the replies !

What would be an "ADSL number"? I am sorry for being able to even understand your question... What I can give you are the information provided by AVM (the manufacturer) Fritz3370 Firmware. There it says something about ADSL2+ if that's what you are asking for?

Thanks a lot for that clarification. The contracted internet speed would be a max of 16 Mbit/s. But even the stock firmware limited itself to about 10 to 12 Mbit/s. Probably because of what you described.
I will have a little read about that SNR offset thingy :slight_smile:

For reference:
The ISP states a minimal download speed of 10 Mbit/s for that connection (sorry for german) Magenta Home S Speeds

Well, data rate, ATTNDR, max dslam rate, error rates and the like... Basically you state OpenWrt gives you less than FritzOS, so I want to know the numbers FritzOS reports to get a feel of how much Kbps difference we are talking about.

Basically I would like to see a screenshot showing these numbers from the stock firmware, if possible ideally not from the far past but from ideally just now with the exact same fritzbox the openwrt numbers came from.

All right, I got you.
Unfortunately that is a hobby project of mine and I am not where the box is right now. Hopefully I can do that next weekend.

No hurry, there are two things I believe worth checking:

  1. Are the "numbers" under OpenWrt really smaller, or have the link's characteristics changed between taking the FB numbers and the OpenWrt numbers? Say, more lines in the same cable bundle simple reduce the SNR and hence the achievable rates.

  2. If 1) shows differences, can these be explained by the vdsl-drivers used by the different firmwares? (This might allow to transplant the FB driver blob into OpenWrt hopefully resulting in similar performance).

Just to update you guys. Sadly I was not able to check for speeds with the native firmware this weekend. But I am still at it and will report back to you as soon as possible,

Hey everyone

I was able to check with a different router but same hardware and stock firmware and it turned out to be a max of 8.2 Mbit/s down and 2.7 Mbit/s up. So really the throughput of the line has changed somehow.

I am a bit confused about that and sorry for troubling you as well as thankful for you guys pointing that out for me!

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