Speed dropped after plan change

Connection issues, drop outs or speed related faults for ADSL and ADSL2+ services
Waughy
Posts: 59
Joined: Wed Aug 24, 2005 11:29 pm
Location: Fern Bay, NSW.

Re: Speed dropped after plan change

Post by Waughy » Mon Mar 09, 2015 7:19 pm

shakows wrote:It shouldnt change unless it rains or someother factors come into it like a faulty filter or unfiltered back to base alarm or something

See how it goes isolated

Maybe also see if you can try a setting that pushes the SNR to around 9
You will loose some speed but it worth trying

The DSL provider should be able to apply a stability profile as well

But I would suggest if its changing then maybe your filter or something else on the line is causing problems

Thanks. I'll keep an eye on it. With the modem plugged directly into the wall socket, and the modem being up for an hour and 20 minutes, the SNR has dropped to 5 so far. It seems to settle around the 3.9 mark, so I was thinking of adding 2 through the modem settings to get it up around 6 and see how it goes. My filters are a te tech N53 DSL008 2+ splitter that has the modem and a cordless phone plugged in normally, a C10 wall plate (no phone connected), and a te tech N53 DSL002 2+ filter with another cordless phone connected, at the opposite end of the house. The te tech splitter and filter are about 4 months old. They were recommended as being quite good, perhaps they aren't. I might try the splitter that came with the modem too, see if it helps at all.

Thanks to all who have had input here. I'll keep at it, but not going to too much trouble to find any (potential) fault. My speeds are reasonable, so no complaints, just looking for anything that might help reduce game lag on Xbox Live mainly.

Cheers.

Waughy
Posts: 59
Joined: Wed Aug 24, 2005 11:29 pm
Location: Fern Bay, NSW.

Re: Speed dropped after plan change

Post by Waughy » Tue Mar 10, 2015 10:12 am

Just checked www.adsl2exchanges.com.au and got the following:
Line of Sight: 1491 m
Estimated Cable: 2311 m
Estimated Attenuation: 32
Estimated Maximum Speed: 12000

I know it's not completely accurate, but an attenuation difference of 12 can't be just bad maths with this site. Got a couple more things to check tonight, then I may need to consider having the line checked out.

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Dazzled
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Re: Speed dropped after plan change

Post by Dazzled » Tue Mar 10, 2015 12:17 pm

Note the ratio between that site's estimated line length and line of sight - it isn't much more than sqrt(2). They have assumed a near square grid of roads. Nelson Bay is a drawn out sort of place, and unlike that assumption.

The common suburban PIUT phone cable, with no faults, attenuates 13.81 dB/km at 300 kHz. That would put you much further from the exchange if there are no line problems. You'd get a better estimate by driving to the exchange.

You can use a modem to investigate several DSL problems, as was discussed at viewtopic.php?f=284&t=40703&p=309013&hi ... 33#p309013 My script is there as well as a link to a compiled solution.

The main point is that the telnet interface of almost all modems can supply values for Hlog, QLN and SNR as arrays ordered by bin frequency. Google DSL loop analysis to give some meaning to this.

Waughy
Posts: 59
Joined: Wed Aug 24, 2005 11:29 pm
Location: Fern Bay, NSW.

Re: Speed dropped after plan change

Post by Waughy » Tue Mar 10, 2015 4:45 pm

Dazzled wrote:Note the ratio between that site's estimated line length and line of sight - it isn't much more than sqrt(2). They have assumed a near square grid of roads. Nelson Bay is a drawn out sort of place, and unlike that assumption.

The common suburban PIUT phone cable, with no faults, attenuates 13.81 dB/km at 300 kHz. That would put you much further from the exchange if there are no line problems. You'd get a better estimate by driving to the exchange.

You can use a modem to investigate several DSL problems, as was discussed at viewtopic.php?f=284&t=40703&p=309013&hi ... 33#p309013 My script is there as well as a link to a compiled solution.

The main point is that the telnet interface of almost all modems can supply values for Hlog, QLN and SNR as arrays ordered by bin frequency. Google DSL loop analysis to give some meaning to this.

Thanks for the informative response. I'll check the link and see if I can get any further info from the modem.

Cheers.

shakows
Posts: 48
Joined: Wed Aug 03, 2005 6:11 pm

Re: Speed dropped after plan change

Post by shakows » Tue Mar 10, 2015 4:51 pm

Waughy wrote:Just checked http://www.adsl2exchanges.com.au and got the following:
Line of Sight: 1491 m
Estimated Cable: 2311 m
Estimated Attenuation: 32
Estimated Maximum Speed: 12000
You modem says otherwise

Line Attenuation Down 44.4 dB

Says you are ~3400m cable distance

Waughy
Posts: 59
Joined: Wed Aug 24, 2005 11:29 pm
Location: Fern Bay, NSW.

Re: Speed dropped after plan change

Post by Waughy » Sat Mar 21, 2015 9:15 am

I may be onto something here with my setup. With it starting at 6 and dropping to around 3.5 for SNR after a reboot I've turned dynamic line adjustment back on, and set stability adjustment to -3. Rx AGC gain is set to stable. I did look into the telnet stuff Dazzled mentioned but got a bit lost. I'm using a mac so might be a bit different.
My stats are now:

DSL Firmware Version 1.0.2.2
DSL Driver Version FwVer:5.5.1.127_A_A60901 HwVer:T14.F7_0.1
DSL Link Status up
DSL Uptime 0 days 18 hours 13 minutes 2 seconds
DSL modulation ITU G.992.5(ADSL2PLUS)
Annex mode ANNEX_A
SNR Down 6.7 dB
SNR Up 7.0 dB
Line Attenuation Down 43.7 dB
Line Attenuation Up 26.1 dB
Path Mode Interleaved
Data Rate Down 7811 kbps
Data Rate Up 1017 kbps
MAX Rate Down 8504
MAX Rate Up 1049
POWER Down 18.8 dbm
POWER Up 11.3 dbm
CRC Down 181
CRC Up 0

Previously after this time my SNR would be 3.7, and my CRC down would be a few thousand (before making the last changes it was around 27,000 after 2 days). My speed is down about 1500-2000, but a small sacrifice if I'm getting a more stable connection.



Also, I'm still seeing this in the general log:

Mar 21 00:19:20 miniupnpd[739]: sendto(udp): Operation not permitted
Mar 21 01:02:21 miniupnpd[739]: sendto(udp): Operation not permitted
Mar 21 02:51:05 miniupnpd[739]: Expired NAT-PMP mapping port 4500 UDP removed
Mar 21 03:59:34 miniupnpd[739]: sendto(udp): Operation not permitted
Mar 21 05:20:58 miniupnpd[739]: Expired NAT-PMP mapping port 4500 UDP removed
Mar 21 06:21:26 miniupnpd[739]: sendto(udp): Operation not permitted
Mar 21 06:46:02 miniupnpd[739]: sendto(udp): Operation not permitted
Mar 21 06:54:02 miniupnpd[739]: sendto(udp): Operation not permitted
Mar 21 07:50:53 miniupnpd[739]: Expired NAT-PMP mapping port 4500 UDP removed

UDP 4500 is meant to be routed to my Xbox, with it's IP ending in XX. Under the port forwarding tab in system log it's showing the port being routed to my Mac, which has an IP ending in XY. The correct IP is set under the port forward tab in the Wan settings for the port.
Any ideas what's going on, and what I can do before logging a problem with Asus?

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Dazzled
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Re: Speed dropped after plan change

Post by Dazzled » Sat Mar 21, 2015 10:33 am

That stuff I linked to is an expect script written in Tcl. You'd have to install these first to run unchanged on a Mac. The idea was to show you how the telnet commands can extract the arrays listing the line test results. For a one-off job, just enter them by hand in a telnet terminal. There are web sites to help understand the interpretation.

I don't have one of your modem/routers, so this is a rather general guide to looking deep inside your router.

These devices run Linux, so NAT and the firewall are being handled by iptables. Logged in on the telnet interface, the command iptables -L should print out the firewall rules. You can then see what the router really does.

When a packet comes in, it is checked against the first rule. Up there is:
ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED
In other words sites you have a currently established relationship (in a table) are let through to the internal computer listed in the table that has that relationship. Otherwise we drop to the next rule, and so on. Eventually there is one that drops everything, for any packet unloved enough to get down that far.

Some rules are grouped in Chains. I'd expect FORWARD to include a chain that eventually has a rule like:
ACCEPT tcp -- anywhere 192.168.1.7 tcp dpt:39670
This is the true port forward rule. So you may check your expected forwarding behaviour with this.

If you are desperate to read the table that lists your connections, where ESTABLISHED etc status is maintained, the terminal command is cat /proc/net/ip_conntrack

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