(DSL) Interleaving: Anyone have it off or on?

[MaxDepth]

I have a bonded DSL line, rated as high as 12 Mbps down, but only getting 8.5 on a good day. Interleaving is turned on, so I wonder if I can get a higher speed with it turned off.

Also for those that have it not on, does the quality really go out the window? (Extreme packet loss?)

 

[JackMDS]

http://www.kitz.co.uk/adsl/interleaving.htm

 

[MaxDepth]

Yeah, I saw that. On paper it should only affect my latency but in practical terms does leaving it on choke my bandwidth?

 

[JackMDS]

It your specific ISP and its configuration that also matter.

Try it.

 

[thecoolnessrune]

Unfortunately for my grandparents, their rural home only gives them Satellite, or DSL as an option (which only came by in 2007). It's now up to 3Mb/s, and runs over copper wires that are about 50 years old.

So for them, they had told me that the Internet gets very slow for them at times. I checked their DSL modem and found that the link was generating tens of thousands of CRC errors every hour.

I worked with AT&T (Bellsouth) to try to improve the line, and with a few truck calls to repair portions of their lines upstream, the situation was better, but still not great. There were still a lot of CRC errors being generated.

Finally, I worked with AT&T and they agreed to switch our connection from FAST to Interleaved. With the Error correction in place, the internet connection stability was night and day better. The 3Mb/s connection now maxes out at around 2.8Mb/s, and latency increased slightly, but that tradeoff was well worth it vs a connection that was only getting 3Mb/s for a couple of hours on a perfect day.

Whether or not you can turn it off really depends on trying it and monitoring the number of CRC errors you collect. If you aren't generating many errors, then there's no point in having it on. But if you get burst noise on your line that cripples transmission, then you may need it to keep a stable connection.

 

[fiberst]

The low Internet speed also has something to do with your network configuration, like the place of router which is advised to be placed in the central house, outside the cabinet and not in the wall.

 

[Harrod]

Interleaving is something that is set on the ISP side, there is no way to shut it off on the modem. That being said it adds latency on the line for error correction. I've seen 12mb DSL lines that were taking heavy errors in fast path speed test at 1.5 mb/s, and when put on interleaving start pulling 10.5 mb/s. The other thing you can do is if the line isn't taking a lot of errors, call your ISP and ask them to set it to "Fast path". The problems with the local loop taking errors can sometimes be fixed by having an installation and repair tech come out and check the line, hopefully if you do this you get someone who isn't lazy. There are a few tricks the good techs can do to remove unnecessary impedance on the lines.

** I've got around 9 years of troubleshooting experience with DSL and Cable modems if you are wondering if I know what I'm taking about.

 

[Gryz]

Interleaving is turned on, so I wonder if I can get a higher speed with it turned off.

I'll repeat what others said: if you disable (turn off) interleaving, your goodput (good throughput, aka speed) will go DOWN. So having it on is good for you.

The only downside of interleaving is that it adds a little bit of latency. The newer the technology, and the higher the bandwidth, the smaller this amount of extra latency will be. I have 8 ms extra latency because of inter-leaving on my 6.5Mbps ADSL2+ line. With VDSL that number might go down to 6 or even 2 milliseconds. And with upcoming technologies (G.Fast and G.Vplus) that number will go down to 1 millisecond. Ignorable.

For most subscribers there is no reason to disable inter-leaving. And if you do, your goodput will most likely suffer quite a bit. So keep it on.

 

[MaxDepth]

Thanks all. I was able to query the router (yay! it stored history) and saw it had more than average to somewhat high error correction rate. So yeah, turning it off will tank my router even more.

HOWEVER...with this high CRC combined with heavy latency in the hours between 7 and 11 PM, it means that I am indeed the last (near last) on the line to the CO and that their line quality is for shit. Right now, I had to put in another ticket because my line has dropped below 5mb this week. The online help people are useless; I had to call twice just to put in a ticket.

Thanks again to all.

 

[bruceb]

One thing you can try for DSL that is fed over copper telephone lines is check how many tel set dsl filters you have in your home. When I was in NJ at nearly 3 miles from the CO my dsl was sometimes very flaky. I fixed it by removing all the little dsl filters and installing a whole house dsl filter where the phone line came in, and running a Cat 5 cable from the filter up to the DSL Modem/Router ... when all was said and done, I got nearly a steady 3MbS download and it never dropped out (with all the filters it would from time to time) ... The reason most homes do not have the whole house filter, is then the Telco would need to send a tech out to install it (instead of DIY install, which is fine if you are close to the CO) and also the added cost of the filter compared to the little ones plugged in at each telephone set.

 

[MaxDepth]

Thanks, Bruce!
In preparation for the bonded DSL, we (Frontier and I) split the copper outside the house. One line is for the all the phone jacks (working or not; it's an old house) and the other dedicated to the modem. This configuration allows me to pull all the filters off. I know we have a ton of squirrels and that this is a legacy Verizon line, but it's now been years. Fiber cannot get here soon enough.

 

[bruceb]

If Frontier split the line like you said, then that is a whole house filter they installed.
Telco line from pole goes into it, and it has 2 outputs .. one for Voice Phone and the other
is Data which is the DSL part to feed your DSL Modem