ZyXEL VMG8623-T50B - Görüş, İstek, Öneri

Merhaba,
2,5 sene sonra güncel FW ile tekrar denemek istedim. Modemi ilk açtığımda 45Mb olan download ~6 saat sonra 3 Mb civarına düşüyor.
(Normalde hızım 55Mb üstünü de görüyor. Sorun yaşamamam için düşürülmüş gibi görünüyor.)
Sadece ZyXEL VMG8623-T50B değil Keenetic modem bağlasam da benzer problem yaşıyorum.

Bu arada bu 2.5 yıl içinde yağmurlu havada bir kez modem arızalandı. Modemi değiştirdim, çözülmedi. Arıza kaydı oluşturduktan sonra düzeldi. Muhtemelen saha dolabında da bir sorun vardı.
Bina dışı kutudan modeme kadar telekomun bağladığı tek kablo geliyor. Farklı ek yok.

Normalde TP-Link TD-W9970v3 operatör modemi kullanıyorum. İlk bağlantı bariz şekilde 2-3 kat daha hızlı. Aylarca açık kalsa değerlerde sapma yok. Keenetic denedikten sonra muhtemelen TD-W9970v3 ile köprü modunda kullanacağım. TD-W9970v3 köprü moduna alırsam yine sorun yok.

Modem açtıktan sonra, 6 saat ve 8 saat sonraındaki değerleri paylaşıyorum;
görüldüğü gibi CRCler artmaya bağlıyor ve noise margin downstream: değeri 0’a doğru yaklaşıyor.

İlk açılış;

=============================================================================
xDSLFwVersion: FwVer:5.12.26.0_B_A60901 HwVer:T14.F7_0.0
Line State: Up
Modulation: ITU G.993.2(VDSL2)
Annex Mode: ANNEX_B

INP downstream: 17918
INP upstream: 14901
shineGINPdownstream: 0
shineGINPupstream: 0
reinGINPdownstream: 0
reinGINPupstream: 0

TPSTC type: 64/65B PTM TC

near-end interleaved channel bit rate: 0 kbps
near-end fast channel bit rate: 45685 kbps
far-end interleaved channel bit rate: 0 kbps
far-end fast channel bit rate: 14093 kbps

near-end FEC error fast: 0
near-end FEC error interleaved: 0
near-end CRC error fast: 0
near-end CRC error interleaved: 0
near-end HEC error fast: 0
near-end HEC error interleaved: 0
far-end FEC error fast: 0
far-end FEC error interleaved: 0
far-end CRC error fast: 1
far-end CRC error interleaved: 0
far-end HEC error fast: 0
far-end HEC error interleaved: 0
DSL uptime :0 min, 29 secs
DSL activetime :0 min, 14 secs

Downstream:
relative capacity occupation: 100%
noise margin downstream: 8.1 dB
output power upstream: 9.4 dbm
attenuation downstream: 13.7 dB

Upstream:
relative capacity occupation: 100%
noise margin upstream: 7.9 dB
output power downstream: 13.9 dbm
attenuation upstream: 2.0 dB


~6 saat sonrası;

xDSLFwVersion:      FwVer:5.12.26.0_B_A60901 HwVer:T14.F7_0.0
   Line State:      Up
   Modulation:      ITU G.993.2(VDSL2)
   Annex Mode:      ANNEX_B

=============================================================================
INP downstream: 17918
INP upstream: 14901
shineGINPdownstream: 0
shineGINPupstream: 0
reinGINPdownstream: 0
reinGINPupstream: 0

TPSTC type: 64/65B PTM TC

near-end interleaved channel bit rate: 0 kbps
near-end fast channel bit rate: 45685 kbps
far-end interleaved channel bit rate: 0 kbps
far-end fast channel bit rate: 14093 kbps

near-end FEC error fast: 54597952
near-end FEC error interleaved: 0
near-end CRC error fast: 3370689
near-end CRC error interleaved: 0
near-end HEC error fast: 0
near-end HEC error interleaved: 0
far-end FEC error fast: 35325162
far-end FEC error interleaved: 0
far-end CRC error fast: 8
far-end CRC error interleaved: 0
far-end HEC error fast: 0
far-end HEC error interleaved: 0
DSL uptime : 6:33, 38 secs
DSL activetime :0 min, 14 secs

Downstream:
relative capacity occupation: 100%
noise margin downstream: 3.3 dB
output power upstream: 9.4 dbm
attenuation downstream: 13.7 dB

Upstream:
relative capacity occupation: 100%
noise margin upstream: 7.8 dB
output power downstream: 13.9 dbm
attenuation upstream: 2.0 dB


~8 saat sonrası;

xDSLFwVersion:      FwVer:5.12.26.0_B_A60901 HwVer:T14.F7_0.0
   Line State:      Up
   Modulation:      ITU G.993.2(VDSL2)
   Annex Mode:      ANNEX_B

=============================================================================
INP downstream: 17918
INP upstream: 14901
shineGINPdownstream: 0
shineGINPupstream: 0
reinGINPdownstream: 0
reinGINPupstream: 0

TPSTC type: 64/65B PTM TC

near-end interleaved channel bit rate: 0 kbps
near-end fast channel bit rate: 45685 kbps
far-end interleaved channel bit rate: 0 kbps
far-end fast channel bit rate: 14093 kbps

near-end FEC error fast: 59316252
near-end FEC error interleaved: 0
near-end CRC error fast: 3719104
near-end CRC error interleaved: 0
near-end HEC error fast: 0
near-end HEC error interleaved: 0
far-end FEC error fast: 39872657
far-end FEC error interleaved: 0
far-end CRC error fast: 8
far-end CRC error interleaved: 0
far-end HEC error fast: 0
far-end HEC error interleaved: 0
DSL uptime : 6:54, 24 secs
DSL activetime :0 min, 14 secs

Downstream:
relative capacity occupation: 100%
noise margin downstream: 1.8 dB
output power upstream: 9.4 dbm
attenuation downstream: 13.7 dB

Upstream:
relative capacity occupation: 100%
noise margin upstream: 8.0 dB
output power downstream: 13.9 dbm
attenuation upstream: 2.0 dB