Can a "too high" sync rate cause instability on my adsl line?

[FlashSA]

We have always had a 4meg line at the office and everything has worked well. Recently our area came on stream for 8meg and I asked Telkom to bump up the line which they did.

I have noticed that the line will sync at the full 8meg but after a while I check back and the sync has lowered to 7meg.

This morning I bounced the router and it synced at the full 8 meg and connected. I wanted the fastest line speed as I have 10GB of dropbox files to upload and every bit helps with our throttled upload speeds...

The problem is that the router kept hanging and disconnecting while dropbox was doing it's thing. After several hours of disabling dropbox to get the connection working again and then enabling, only to have it all lock up, I have noticed that the router must have resynced and is now on 7meg.......

Funnily enough, now on 7meg, dropbox is uploading fine and the office has full internet access..... Based on my line noise values 8meg is the max which my line can take - is there a chance that by syncing on the limit, this was causing instability when dropbox was maxing the upload?

 

[Sinbad]

Yes. Syncing on the limit will be less stable

 

[DrJohnZoidberg]

What do your line stats look like?

Also, if you need it mostly for uploading there isn't going to be a difference between 8Mbit or 7Mbit as that is your download speed. I would suggest you ask Telkom to sync you at the speed where your line is most stable.

 

[FlashSA]

What do your line stats look like?

Also, if you need it mostly for uploading there isn't going to be a difference between 8Mbit or 7Mbit as that is your download speed. I would suggest you ask Telkom to sync you at the speed where your line is most stable.

Modem Status Connected
DownStream Connection Speed 7072 Kbps
UpStream Connection Speed 896 Kbps
VPI 8
VCI 35

ADSL Link Downstream Upstream
Link Rate 7072 Kbps 896 Kbps
Line Attenuation 36.0 dB 25.5 dB
Noise Margin 8.5 dB 6.0 dB

 

[DrJohnZoidberg]

Modem Status Connected
DownStream Connection Speed 7072 Kbps
UpStream Connection Speed 896 Kbps
VPI 8
VCI 35

Need your line quality stats too. It should say something along the lines of "Line attenuation" and "SNR" or "Noise Margin" - those are the important numbers.

 

[ISP cash cow]

Modem Status Connected
DownStream Connection Speed 7072 Kbps
UpStream Connection Speed 896 Kbps
VPI 8
VCI 35

ADSL Link Downstream Upstream
Link Rate 7072 Kbps 896 Kbps
Line Attenuation 36.0 dB 25.5 dB
Noise Margin 8.5 dB 6.0 dB

Your attenuation and noise values from your modem would be required in order to see how long and noisy your line is at those speeds

 

[FlashSA]

Need your line quality stats too. It should say something along the lines of "Line attenuation" and "SNR" or "Noise Margin" - those are the important numbers.

Sorry, I edited my original post.... here are those details:

ADSL Link Downstream Upstream
Link Rate 7072 Kbps 896 Kbps
Line Attenuation 36.0 dB 25.5 dB
Noise Margin 8.5 dB 6.0 dB

 

[FlashSA]

Your attenuation and noise values from your modem would be required in order to see how long and noisy your line is at those speeds

I can do a resync to 8MEG tomorrow morning when no one is here and then post those results

 

[ISP cash cow]

Sorry, I edited my original post.... here are those details:

ADSL Link Downstream Upstream
Link Rate 7072 Kbps 896 Kbps
Line Attenuation 36.0 dB 25.5 dB
Noise Margin 8.5 dB 6.0 dB

Those noise margins seem quite low even on the 7Mb sync so I would imagine that they would be even worse on the 8Mb speed. You may find on your 7Mb connection that you may still get disconnected but just not as often. here is the rough guideline for noise margins

6dB or below noise margin is bad, it will experience no synch or intermittent synch problems
7dB-10dB is fair but does not leave much room for variances in conditions
11dB-20dB is good with little or no synch problems (if no large variation)
20dB-28dB is excellent
29dB or above is outstanding

 

[DrJohnZoidberg]

Those noise margins seem quite low even on the 7Mb sync so I would imagine that they would be even worse on the 8Mb speed. You may find on your 7Mb connection that you may still get disconnected but just not as often. here is the rough guideline for noise margins

6dB or below noise margin is bad, it will experience no synch or intermittent synch problems
7dB-10dB is fair but does not leave much room for variances in conditions
11dB-20dB is good with little or no synch problems (if no large variation)
20dB-28dB is excellent
29dB or above is outstanding

Agreed. I would probably leave it at 7Meg.

 

[FlashSA]

Things have definitely settled down now that my router has downsynced to 7mb...... dropbox is pumping away and everyone in the office is happy with a stable connection.

I learnt something today..... might need to get Telkom to lock my line on 7MB

 

[Nerfherder]

Things have definitely settled down now that my router has downsynced to 7mb...... dropbox is pumping away and everyone in the office is happy with a stable connection.

I learnt something today..... might need to get Telkom to lock my line on 7MB

Usually they resync at the last speed that it connected at... so generally you have to fight with them to push the line up. It will find its own way down magically.

 

[Dan C]

Things have definitely settled down now that my router has downsynced to 7mb...... dropbox is pumping away and everyone in the office is happy with a stable connection.

I learnt something today..... might need to get Telkom to lock my line on 7MB

Are you still having problems ? At about the time of your post, the very same thing happened here in Beacon Bay. Must have dropped and re-synced about 5 - 6 times.. Seems fine now.

 

[FlashSA]

Are you still having problems ? At about the time of your post, the very same thing happened here in Beacon Bay. Must have dropped and re-synced about 5 - 6 times.. Seems fine now.

It was over a period of 2hrs this morning - 10am to 12pm..... Everything is fine now though although the router is slower at 7mb whereas it was at 8mb this morning

 

[Dan C]

It was over a period of 2hrs this morning - 10am to 12pm..... Everything is fine now though although the router is slower at 7mb whereas it was at 8mb this morning

I had problems at those times too. I never lose sync so Telkom did something.. My max sync normally said 8 now showing max 5.

 

[Tim the Techxpert]

Hi there,
Looking at your stats I would leave the line at 7mb. Your empirical tests seem to bear that out as well. The extra 1mb will not make a significant difference to you and what you are trying to do.

regards

Tim

 

[ichigo]

It was over a period of 2hrs this morning - 10am to 12pm..... Everything is fine now though although the router is slower at 7mb whereas it was at 8mb this morning

Looks fine for 7 meg since you 6 and 8.5 db higher than the minimum required to sync.

You can push 8 meg but may cause problems.