Regular Connection Drops (Vigor 2820)

Hello,

We've been having problems with our connection dropping at regular intervals along with slow browsing and download speeds and I'm trying to ascertain the possible causes. We're using a Draytek Vigor 2820 router.

Here's the ADSL Status:

--------------------------- ATU-R Info (hw: annex A, f/w: annex A) -----------
Running Mode : ADSL2+(G.992.5) State : SHOWTIME
DS Actual Rate : 8024000 bps US Actual Rate : 1039812 bps
DS Attainable Rate : 8144000 bps US Attainable Rate : 1040000 bps
DS Path Mode : Fast US Path Mode : Fast
DS Interleave Depth : 1 US Interleave Depth : 1
NE Current Attenuation : 54 dB Cur SNR Margin : 6 dB
DS actual PSD : 20. 3 dB US actual PSD : 12. 6 dB
ADSL Firmware Version : 232201_A
-------------------------------- ATU-C Info ---------------------------------
Far Current Attenuation : 27 dB Far SNR Margin : 6 dB
CO ITU Version[0] : 00004946 CO ITU Version[1] : 0000544e
DSLAM CHIPSET VENDOR : < IFTN >

I've checked the log and each time it disconnects, the following few lines occur - the same every time:

71:00:24.230 PPP Closed : Remote Terminating (PPPoA)
71:00:30.890 PPP Start (PPPoA)
71:00:32.010 CHAP Login OK (PPPoA)
71:00:32.030 IPCP Opening (PPPoA)

I've also noticed when viewing the Physical Connection Online Status page that every time the page refreshes (5 second intervals), the number of RX Cells increases by one, yet the number of RX CRC Errors increases by approximately 300.

Surely it's not normal to be receiving over 300 of them every 5 seconds - it's regularly getting to about 60,000 then the counter resets itself.

We've upgraded the firmware to latest version, changed filters, rebooted router and recently requested an SNR Profile Reset. I was thinking about changing the Modulation to G.DMT (ADSL) as the line is only capable of 8meg. It's currently set to Multimode and seems to be choosing G.992.5. Also, would changing the path mode to Interleaved from Fast help, do you think?

Any ideas most appreciated chaps.

Many Thanks,
Matt

8Meg sync at 54dB attenuation is pretty amazing, something more like 4Meg is what I'd expect to see.

It may be your router is pushing the line too hard and getting errors.

Try ADSL2 mode (G.992.3) first, then drop to ADSL only (G.992.1) if that does not help.

Interleaving can help the line tolerate errors, at the expense of a little latency, but usually needs provider to switch it on. i the mode changes and interleave don't work, then a 9dB target margin might be the next step.

Thanks, Andrew. I'll see if we can get the modulation changed to see if this helps. Do you know whether or not the extremely high RX CRC Error Count could be causing any issues - or rather, what kind of things can cause these errors?

Matt

Large number of errors can cause re-transmits of data, thus give you a slower or intermittent connection

What causes the errors - anything that can make an AM radio crackle and pop

What version of firmware are you using? You should see the firmware version on the admin page when you login.

The firmware is 3.3.7_232201_A which I believe is the latest one. We're still having a number of issues even when we've changed modulation. It takes about 60 seconds to load the BBC website, pinging from a workstation shows the same speed as it does if we ping from the router - between 35-40ms which I would've though is fairly normal.

Confused as to what to try next.

In reply to a post by Xylo:

..... It takes about 60 seconds to load the BBC website.....

Is this a Be/O2 based connection?

Nope - don't think so, ISP is ClaraNet.

Hi - sorry to dredge but did you ever find a solution? Very similar things happening on my 2830 now

Tom

hi

draytek does 3 types of firmware - adsl2+ annex m lines, regular lines and lower quality lines. apart from what the others suggested, try using the 211801 firmware for lower quality lines, available here: http://www.draytek.co.uk/support/downloads.html (choose the alternative firmware). Let us know how you get on.