Should my line sync faster to the exchange

I've recently gone over to Talk Talk's up to 24meg LLU service, and according to various checks before hand, by line should get close to 19meg sync

My current router (DG834G) syncs with the following stats

Downstream
Connection Speed - 16122kbps
Line Attenuation - 17.5db
Noise Margin - 12.1db

Upstream
Connection Speed - 827kbps
Line Attenuation - 6.6db
Noise Margin - 12.4db

The current sync gives me the following speeds

http://speedtest.net/result/1885157926.png

I did originally give Talk Talk a call and they put me on their 'highest profile', which stayed stable with no connection drop outs, but my download speeds dropped to 5meg

As you can see by my router stats, I am very close to my exchange, so was just expecting a higher sync and hence higher download and upload speeds

Is it normal for a higher sync to mean slower download speeds, or did Talk Talk do something to limit my speed when I synced higher so forcing me to call again which meant they could use that as an excuse to lower the sync?

During the period of the 'highest profile' my connection was rock solid and synced at just over 18000kbps and the noise margin dropped to 6.5db

When on my old BT up to 8meg Max connection I was syncing at 8192kbps and 1012kbps, which is just about the maximum you can get, so was expecting close to the maximum on Talk Talk's up to 24meg LLU connection

Also my ping has doubled from 22ms to 49ms since moving to LLU from BT

Am I just expecting too much?

Any clarification would be grateful before I call Talk Talk again

Thanks

Edited by deleted (Tue 10-Apr-12 02:51:35)

In reply to a post by ntm1275:

I've recently gone over to Talk Talk's up to 24meg LLU service, and according to various checks before hand, by line should get close to 19meg sync

My current router (DG834G) syncs with the following stats

Downstream
Connection Speed - 16122kbps
Line Attenuation - 17.5db
Noise Margin - 12.1db

Upstream
Connection Speed - 827kbps
Line Attenuation - 6.6db
Noise Margin - 12.4db

The current sync gives me the following speeds

http://speedtest.net/result/1885157926.png

I did originally give Talk Talk a call and they put me on their 'highest profile', which stayed stable with no connection drop outs, but my download speeds dropped to 5meg

As you can see by my router stats, I am very close to my exchange, so was just expecting a higher sync and hence higher download and upload speeds

Is it normal for a higher sync to mean slower download speeds, or did Talk Talk do something to limit my speed when I synced higher so forcing me to call again which meant they could use that as an excuse to lower the sync?

During the period of the 'highest profile' my connection was rock solid and synced at just over 18000kbps and the noise margin dropped to 6.5db

When on my old BT up to 8meg Max connection I was syncing at 8192kbps and 1012kbps, which is just about the maximum you can get, so was expecting close to the maximum on Talk Talk's up to 24meg LLU connection

Also my ping has doubled from 22ms to 49ms since moving to LLU from BT

Am I just expecting too much?

Any clarification would be grateful before I call Talk Talk again

Thanks

The target SNR being set to 12db is limiting your sync speed, on such a short line you shouldn't see problems with the target snr set to 6db or 3db, another setting that would more than likely give the sync a increase is fastpath , this will also give you lower ping times, but it may sometimes cause disconnections,(from outside noise/interference

But the only way you have of finding out is to try it and see really as almost every line is in some way different with a 3db margin and fastpath enabled you could see over 19mbits maybe 22 mbit even

Call Talktalk again and ask to be put on a '24FSNR6' profile. Or even better request it via their forums eg
http://www.talktalkmembers.com/forums/showthread.php...

This will
a) lower your noise margin to 6db (the lowest they will go officially) resulting in a higher sync
b) put you on a fastpath profile resulting in lower pings - great for gaming and voip applications.

This should give you a sync speed of 18-19 meg but use the talktalk speedtester to measure your speeds; they should be at least 15 meg. Give it a few days and if you're happy then i suggest getting a broadcom router (eg most Netgears) and lower your downstream noise margin to 2-3 db which should give you a sync speed of 20-22 meg

Is there any technical reason that a higher sync would mean considerably lower download speeds?

As I mentioned in my previous post, I was originally put on their 'highest profile', with a sync about 18000kbps but then my download speeds dropped to 5meg

Now that I'm back on 16122kbps, speeds have increased to 13.92mbs

I'm just trying to gather as much information before giving them a call to alter the sync again

In reply to a post by baby_frogmella:

Call Talktalk again and ask to be put on a '24FSNR6' profile. Or even better request it via their forums eg
http://www.talktalkmembers.com/forums/showthread.php...

This will
a) lower your noise margin to 6db (the lowest they will go officially) resulting in a higher sync
b) put you on a fastpath profile resulting in lower pings - great for gaming and voip applications.

This should give you a sync speed of 18-19 meg but use the talktalk speedtester to measure your speeds; they should be at least 15 meg. Give it a few days and if you're happy then i suggest getting a broadcom router (eg most Netgears) and lower your downstream noise margin to 2-3 db which should give you a sync speed of 20-22 meg

the OP is already using a router with a broadcom chip My current router (DG834G) syncs with the following stats So can tweak the downstream lower even on the native fw. if the dgteam fw is used then the tweak survives a router power cycle

In reply to a post by ntm1275:

Is there any technical reason that a higher sync would mean considerably lower download speeds?

As I mentioned in my previous post, I was originally put on their 'highest profile', with a sync about 18000kbps but then my download speeds dropped to 5meg

Now that I'm back on 16122kbps, speeds have increased to 13.92mbs

I'm just trying to gather as much information before giving them a call to alter the sync again

No as they advertise the max theoretical sync of 24mbit, if you sync at 19mbit then you should get around 15.7mbit throughput maybe more , as a general rule the higher the sync the higher the throughput is
What did you use to conclude that you wasn't getting the correct throughput ? speedtest sites do not provide accurate results,

better to download a test file from somewhere, 1000mb test file is one i have used or you have test files on this site too ,

sometimes using only a single stream 1 connection to the server, the throughput wont max out , so use of a download manager is a good option as most will support multiple connections to the server

The other things that can sometimes play a part is getting the most throughput is the MTU size what is it set to on your router ?

I only used the speedtest.net checker as a guide

When on the 'highest profile', it was only showing 5meg download speed

As soon as I called them and they lowered the profile (and the sync speed) my speeds immediately went up to 13.92meg

The router is currently set to 1458 MTU

In reply to a post by ntm1275:

I only used the speedtest.net checker as a guide

When on the 'highest profile', it was only showing 5meg download speed

As soon as I called them and they lowered the profile (and the sync speed) my speeds immediately went up to 13.92meg

The router is currently set to 1458 MTU

It could indicate some sort of problem with the line itself or the line card ect at the exchange, or could of been the server load at the time, that you selected on speedtest.net , but as you are no longer on that profile,it's impossible to know what the cause was,It could of even been down to the ISP's Network at the time if you decide to try again,and the same thing happens

Next time set up a quality meter then providing the ip doesn't change you will be able to see if there is any packet loss causing the low throughput, you could also download and use routerstats and DMT , which will provide you with a lot more info as to what is going on, such as error rates and missing or depleted tones , I'm not saying that we can fix it, but if nothing else you would probably get a good idea as to what was going on

Edited by tommy45 (Wed 11-Apr-12 04:56:06)

Or the line was pushed to its absolute maximum and lots of ATM cells had to be retransmitted over the line to get an IP frame delivered.

In short error count may have been very high, but without any data to support this it is speculation, but we have seen this happen in the past, if you push the noise margins so hard that noise is swamping the signal

In reply to a post by tommy45:

the OP is already using a router with a broadcom chip My current router (DG834G) syncs with the following stats

Only if it is a v4.