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errold32
join:2014-09-26
USA

errold32

Member

[Qwest] Modem periodically Disconnects / never achieves paid for speed

Modem: GT784WN
Paid for Speed:20Mb/s down

Problem:Intermittent connectivity drops requiring modem restart. Slower then expected speeds. Please don't cite the 85% charts......

See line stats below. SNR looks low. Tech-support says line is fine, and never talked hard numbers. (RRRRRRR)
Support says modem may be bad, which is a possibility.

I am looking for someone with some actual knowledge to look at this for me.

Thanks

These are inside numbers. NID numbers to follow...
WAN Status
Connection Status
Connection Status
Broadband: CONNECTED
Internet Service Provider: CONNECTED

PPP Status
PPP Parameter Status
User Name: *******@qwest.net
PPP Type: PPPoE
LCP State: UP
IPCP State: UP
Authentication Failures: 0
Session Time: 0 Days, 4H:24M:26S
Packets Sent: 597071
Packets Received: 913934

Broadband Status
Broadband Parameter Status
VPI: 0
VCI: 32
Broadband Mode Setting: MULTIMODE
Broadband Negotiated Mode: ADSL2+
Connection Status: CONNECTED
Downstream Speed: 18142 Kbps
Upstream Speed: 892 Kbps
Retrains: 0
Retrain Timer: 0 Days, 4H:24M:31S
ATM QoS class: UBR
Near End CRC Errors Interleave: 0
Near End CRC Errors Fastpath : N/A
Far End CRC Errors Interleave : 0
Far End CRC Errors Fastpath : N/A
30 Minute Near End CRC Interleave : 0
30 Minute Near End CRC Fastpath : N/A
30 Minute Far End CRC Interleave : 0
30 Minute Far End CRC Fastpath : N/A
Near End RS FEC Interleave : 0
Near End RS FEC Fastpath : N/A
Far End RS FEC Interleave : 0
Far End RS FEC Fastpath : N/A
30 Minute Near End FEC Interleave : 2342
30 Minute Near End FEC Fastpath : N/A
30 Minute Far End FEC Interleave : 0
30 Minute Far End FEC Fastpath : N/A
30 Minute Discarded Packets Downstream : 0
30 Minute Discarded Packets Upstream : 0
SNR Downstream : 11 dB
SNR Upstream : 20 dB
Attenuation Downstream : 15 dB
Attenuation Upstream : 7 dB
Power Downstream 0 dBm
Power Upstream 10.8 dBm
BadMagpie
join:2011-02-05

BadMagpie

Member

The SNR levels don't look too bad; I occasionally get 5 dB SNR down without dropouts, but I'm on VDSL2 8a.
The first thing I'd try is enabling Seamless Rate Adaptation. The modem will try to adjust the line rate without disconnecting if the noise on the line changes.

Telnet into the modem and run "adsl start --sra on".
errold32
join:2014-09-26
USA

1 edit

errold32

Member

ok. Did it. Is there any indication of this change in the GUI? speed changes etc?

my downstream rate used to be 21Mb/s. It changed to 18142kb/s sometime, I don't know why. Centurylink gave me some baloney about there being a section reserved for upstream rate as the reason for the change. last time I checked, my upstream rate is 892 Kbps, which when added to 18142kbps doesn't even equal 20Mbps (my paid for speed) am I wrong? I don't think so.....
errold32

1 edit

errold32

Member

Updated numbers (inside) with Near End CRC Errors Interleave: 453
errold32

2 edits

errold32

Member

and 2 retrains
BadMagpie
join:2011-02-05

BadMagpie to errold32

Member

to errold32
See if the speed is any lower than that. I don't see why it would be disconnecting at this stage. I know my own modem will retrain if I plug or unplug things from other phone lines around the house.

You can use adsl profile --show to verify that sra is on.

Some other things you can try to add are turning Physical layer Retransmission on both the up and downstream, and lowering the SNR margin. Try this:

adsl start --phyReXmt 0x03 --sra on --snr 50

If that still doesn't work I may be tempted to try another modem.
gapmn
join:2013-11-10
Saint Paul, MN

gapmn to errold32

Member

to errold32
Ask if you can get switched over to a VDSL2 connection. I used to have a 20Mb ADSL connection and it would never sync to my proper connection speed. A CL tech came out to check my line and found no problems. He said since I already had a modem that could handle a VDSL connection he would try to get engineering to allow me to switch over to VDSL. Of course engineering was stubborn and didn't want to give up a VDSL port for my 20Mb connection. In the end, after numerous calls, and running some test overnight, engineering finally allowed the VDSL connection change over. I have not had any trouble since the changeover (that was three years ago). I currently have a over-provisioned 50/5 connection.