ADSL line / router - Much oddness here!

Soldato
Joined
27 Feb 2003
Posts
7,354
Location
Shropshire
Bog standard ADSL connection via Enta, router is/was a Cisco 857.

Site was fine until a few weeks ago and went off-line. Investigations showed it wasn't synch'ing.

Bit of leg work later, we tried a (cheap & nasty) Billion 7402R2 which sync's but has the world's most unstable VPN tunnels.

I'm working on the problem today and I've got 3 Cisco 857s with me. One is the original router, the CD light just flashes a lot. The 2nd 857 with the same config as the 1st 857 on does the same. The 3rd 857 is brand new and I've done a very basic config on the ADSL interface and that just sits there flashing the CD light too.

I've also got a Draytek Vigor 100 - that won't sync.

However, the Billion 7402R2 sync's within 30 seconds of connecting it and reports 3,584,000 downstream and 736,000 upstream. Line stats are:

Downstream : 12.5db SNR, 48.5db Attenuation
Upstream : 5db SNR, 29db Attenuation

Next up I've tried a Speedtouch 546 v5. That sync'd, dropped the DSL and then has stayed up. This is showing:

Bandwidth (Up/Down) [kbps/kbps]: 832 / 3,392
Output Power (Up/Down) [dBm]: 12.0 / 18.5
Line Attenuation (Up/Down) [dB]: 29.5 / 47.5
SN Margin (Up/Down) [dB]: 6.0 / 14.0

The routers all go into the master socket which has a faceplate from an OCuk competitor that sells (IMHO) good quality filters.

Doing a quiet line test via 17070 shows nothing static-wise.

Is this just a really noisy line and the Cisco + Draytek routers can't hack it?

:confused:
 
I found the if anything my Ciscos were more stable than anything else albeit that they didn't sync as high. I had a 837, and 1721 with 1xWIC-1ADSL and an 1841 with 2xWIC-1ADSLs and my line was MUCH worse that yours.

Of the top of my head I had 59dB loss and at 6dB margin I'd get about 3.5Mb and I was getting upto 16,000 HECs a second and it still chugged along fine.

You've got a 14dB margin so that shows signs that something has been playing up to increase it.
 
It's very strange.

I've tried some of the newer Cisco ADSL firmware files - 3.0.10 and 3.0.33 but still no sync. I've also manually specified the DSL operating-mode instead of using "dsl operating-mode auto"

I've just synch'd up the Speedtouch again and that reports these vendor codes:

Vendor ID (Local/Remote): TMMB / P

Who is P?

I've just logged onto a couple of other 857s I know are working and they report STMI, TSTC or ALCB. They are running on the built in ADSL firmware (3.0.14).
 
Would you believe it?

Both the 1st 857 and the Vigor 100 sync'd on my home Enta line with no configuration changes...

So what do BTW do to a break a line for certain CPE?
 
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