Random DL speed changes on Spark ADSL

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othello13

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#150978 9-Aug-2014 17:07

Hi all,

I am a new Spark (Telecom) ADSL customer (new to ADSL in general- cable internet previously) and have noticed that the service, particularly the speed, is very unreliable and poor. Now I understand that the speed of an ADSL service is influenced by many factors, e.g. internal house wiring, distance to the exchange/DSLAM box, network load, etc. but I'm seeing quite a random change- drop and rise on the line speed reported by the modem stats. Let me describe my observations.

Upon first (new) connection, the speed test results showed a speed of about 1.2Mbps down and 0.8Mbps up, 30ms ping. I am in suburban Wellington and about 1.6km from the nearest exchange. To me these stats and performance seemed pretty awful.

The next couple of days I noticed that after every modem reboot or the one-off DSL line drop-out, after the subsequent DSL synchronisation by the modem, the reported modem stats changed dramatically- downstream (and upstream) line rates swung from 4000+ kbps (1500 kbps) to 300 kbps (300 kbps)! The performance on the speed test website reflected these modem-reported stats, where at one point at its lowest, I could barely load a webpage.

I called up the tech desk and they asked me to perform a speed test with them on the other end, and they could confirm that the speed was unusually low (about 0.3 Mbps at this stage) and said that they noticed that that was the line speed sent out from the exchange itself. Hours after another modem reboot, the line speed was back up at around 4 Mbps, only for the DSL connection to drop out and the speed returning down to about 1.3 Mbps.

This behaviour, either by the modem (HG630b) or the actual provisioning of the ADSL service, seems VERY bizarre to me, not to mention annoying and under-performing. I'm attaching the latest stats reported by the modem.

Line standard ADSL2+ Channel type Interleaved Downstream line rate (kbit/s) 1101 Upstream line rate (kbit/s) 733 Downstream SNR (dB) 12 Upstream SNR (dB) 10.9 Downstream line attenuation (dB) 36.5 Upstream line attenuation (dB) 23.4 Downstream output power (dBmV) 18.8 Upstream output power (dBmV) 12.4 Downstream CRC 0 Upstream CRC 0 Downstream FEC 0 Upstream FEC 0

Has anybody else experienced similar issues or is anyone able to shed some light as to what and why this could be happening? Your help is much appreciated!

Chur!

Edit: Latest speed test; painfully slow DL.
<a href="https://www.speedtest.net/my-result/3677932576"><img src="https://www.speedtest.net/result/3677932576.png" /></a>

PeterReader

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#1105510 9-Aug-2014 17:07

Hello... Our robot found some keywords in your post, so here is an automated reply with some important things to note regarding broadband speeds.

If you are posting regarding DSL speeds please check that

- you have reset your modem and router

- your PC (or other PCs in your LAN) is not downloading large files when you are testing

- you are not being throttled by your ISP due to going over the monthly cap

- your tests are always done on an ethernet connection to the router - do not use wireless for testing

- you read this topic and follow the instructions there.

Make sure you provide information for other users to help you. If you have not already done it, please EDIT your post and add this now:

- Your ISP and plan

- Type of connection (ADSL, ADSL2, VDSL)

- Your modem DSL stats (do not worry about posting Speedtest, we need sync rate, attenuation and noise margin)

- Your general location (or street)

- If you are rural or urban

- If you know your connection is to an exchange, cabinet or conklin

- If your connection is to a ULL or wholesale service

- If you have done an isolation test as per the link above

Most of the problems with speed are likely to be related to internal wiring issues. Read this discussion to find out more about this. Your ISP is not intentionally slowing you down today (unless you are on a managed plan). Also if this is the school holidays it's likely you will notice slower than usual speed due to more users online.

A master splitter is required for VDSL2 and in most cases will improve speeds on DSL connections. Regular disconnections can be a monitored alarm or a set top box trying to connect. If there's an alarm connected to your line even if you don't have an alarm contract it may still try to connect so it's worth checking.

I recommend you read these two blog posts:

- Is your premises phone wiring impacting your broadband performance? (very technical)

- Are you receiving a substandard ULL ADSL2+ connection from your ISP?

I am the Geekzone Robot and I am here to help. I am from the Internet. I do not interact. Do not expect other replies from me.

hio77

12999 posts

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Lizard Networks

#1105522 9-Aug-2014 17:10

ild say your best bet is to have a master filter installed.

sounds likely a contact is possibly a little loose..

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Any comments made are personal opinion and do not reflect directly on the position my current or past employers may have.

Ragnor

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#1107183 12-Aug-2014 17:38

Sounds like there is an issue with your wiring somewhere along the way, keep going with the help desk process. Next step will likely be them sending a tech out.