Billion UK Forum

I am trying to turn off the trellis in the ADSL config of my Billion 7800. The reason is that I would like to see what effect, if any, this has on performance. The trellis appears to be on by default.

As far as I can see, the trellis settings aren't accessible via the web-based router interface, but they are accessible via the telnet interface.

After telnetting into the router, I enter this command, which is accepted:

adsl configure --trellis off

But now there is a problem about how to save this setting. When I enter this command:

adsl profile --save

I get this message:

"adsl profile --save: only supported from Linux404 on ward"

Where do I go from here, please? Many thanks.

After turning Trellis off and logout out of telnet, what does its status show as when you log back in ?

Disabling Trellis could increase the latency or loss of data as I understand it. http://www.kitz.co.uk/adsl/error_correction.htm

Thanks for responding.

As might be expected, if config changes aren't saved before logging out of the router's telnet interface, the changes are lost.

No doubt the trellis has advantages in handling potential network snags. However, I've found that on another Billion router (the 7700N) turning off the trellis results in a noticeable improvement in downstream sync.

By the way, several other ADSL config options also show up in the telnet interface but not in the web-based interface: bitswap, sesdrop, CoMinMgn, 24k, TpsTc and monitorTone. Given that the 7800 is supposed to be a pro-level router, it's a mystery why all the settings aren't accessible via the web-based interface.

I turned Trellis off in mine and when I logged back into telnet, it was showing as U:ON/D:OFF and it had rebooted the link uptime (not a full router reset) with a resync speed of 4861 which was down from 6453.

Logged out then back in to turn Trellis back on and it resync'd at 5565 so not sure where the higher sync speeds come from with it turned off.

The reason the sync speed wasn't fully restored is probably due to the time of day with a lower SNRM as I normally have as the day wears on.

Don't know why the cmds only acted upon the Downstream Trellis but it did remain as per the cmd after logging out then back in and without any save config.

I don't know if this would have been true if I had rebooted the laptop as I've performed these cmds as I've been writing this post.

There was an earlier thread I was involved with on the forum where an OP had requested the telnet access options and I'd noticed in his output that he'd posted, that Trellis was off for both Up and Down and gave him the cmd to turn it on and he didn't report that it hadn't taken so it looks like no two 7800Ns are a like ?

I've never understood why the line stats aren't available in the Interface and that you have to view them via telnet.

I've figured out how to save the settings. Instead of entering the detailed command adsl profile --save, I just have to enter the simple command save. Obviously I was being too clever by half!

At the moment it looks as though turning off the trellis results in a small improvement in downstream sync, although this could be just a random variation. Certainly not a decrease, though.

Thanks again for commenting.

Brian49 wrote:I've figured out how to save the settings. Instead of entering the detailed command adsl profile --save, I just have to enter the general command save. Obviously I was being too clever by half!

At the moment it looks as though turning off the trellis results in a small improvement in downstream sync, although this could be just a random variation. Certainly not a decrease, though.

Thanks again for commenting.

Your problem on how to save the telnet cmd Solved, mine as to why it only turned the Downstream Off..... Unresolved

On my router, the trellis is either on or off; there is no U/D parameter. Perhaps you should start a separate thread to address that issue.

Brian49 wrote:On my router, the trellis is either on or off; there is no U/D parameter. Perhaps you should start a separate thread to address that issue.

It doesn't really matter as I'll be leaving it on and it must be as I'd said, that no two 7800Ns seem to be the same